Vat Lieu Polyme Blend

7/25/2019 Vat Lieu Polyme Blend

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VT LIU POLYME BLEND

Nh xut Bn khoa hc t nhin v cng ngh

Vin khoa hc v cng ngh vit nam

THI HONG


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5

Mc lc

Li gii thiu bsch chuyn kho 3Cc tvit tt 7

Li gii thiu 9

Li ni u 11

Mu 13

Chng I. Nhng vn chung ca polyme blend 15

I.1. Mt skhi nim vpolyme blend

15I.2. Nhit ng hc qu trnh ho tan cc polyme 16

I.3. Gin pha v chuyn pha ca hn hp cc polyme 24

I.4. Cc dng polyme blend 32

I.5. Slc lch spht trin v ng dng ca polyme blend 35

Ti liu tham kho 40

Chng II. Cc phng php xc nh stng hp ca

cc polyme

45

II.1. Phng php gin pha 45

II.2. Phng php da vo nhit thutinh ho 50II.3. Phng php da vo nht dung dch polyme blend 62

II.4. Phng php da vo m - men xon ca polymeblend trng thi nng chy

70

II.5. Phng php da vo tnh cht chc 78

II.6. Phng php da vo phhng ngoi 89

II.7. Phng php da vo nh hin vi

96

II.8.-Cc-phng-php-khc-nh-gi-kh-nng tng hpca cc polyme

106

II.9. Kt hp cc phng php nh gi kh nng tnghp ca cc polyme

108

Ti liu tham kho 110


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Thi Hong6

Chng III. Cc phng php chto vt liu polyme blend 123

III.1. Chto polyme blend tdung dch polyme 123

III.2. Chto polyme blend trng thi nng chy

125

III.3. Phng php lu ho ng 143

III.4. Trng hp monome trong mt polyme khc 155

III.5. Phng php to cc mng li polyme an xen 157

III.6. Cc phng php khc chto polyme blend 164

Ti liu tham kho 166

Chng-IV.-Cc-bin-php-tng-cng-tng-hppolyme blend

175

IV.1. Bin tnh polyme 176

IV.2. Sdng cc cht tng hp l polyme 177

IV.3. a vo cc hp cht thp phn t 199

IV.4. Cc phn ng chuyn v 205

IV.5. a vo hcc cht khu mch chn lc v lu ho ng 209

IV.6. Cc tng tc c bit trong polyme blend 215

IV.7. a vo cc ionome 222

IV.8. To cc mng li polyme an xen nhau 226

IV.9. Cc phng php khc tng cng tng hp ccpolyme

228

Ti liu tham kho 232


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7

Cc tvit tt

AA: axit acrlylic

ABS: copolyme styren- butadien - acrylonitril

AES: cao su etylen-propylen-dien ghp copolyme

styren-acrylonitril

AFM: hin vi nguyn tlc

AN: acrylonitril

CAB: xellulo axetat butyrat

CSTN: cao su thin nhin

DCP: dicumyl peoxit

DMA: phn tch chc ng

DMTA: phn tch cnhit ng

DSC: nhit lng vi sai qut

EAA: copolyme etylen-axit acrylicEMA: copolyme etylen-co-axit metacrylic

EPDM: etylen-propylen-dien monome

EP-g-MA: cao su etylen-propylen-g-anhydrit maleic

EPDM-g-MMA: EPDM ghp metyl metacrylat

EPDM-MA: copolyme EPDM-anhydric maleic

EVA: copolyme etylen-co-vinyl axetat

EVOH: copolyme etylen-co-vinyl alcol

FTIR: phhng ngoi bin i Fourier

GMA: glyxidyl metacrylat

HIPS: PS bn va p

HBP: poly(amit-este) siu nhnh


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Thi Hong8

HNBR: cao su butadien-nitril hydro ho

HPB: polybutadien hydro ho

IPN: mng li cc polyme an xen

(interprenetrating polymer networks)

LCP: polyme tinh thlng

LCST: nhit ho tan ti hn di

LDPE: polyetylen ttrng thp

LDPE-g-AA: LDPE ghp axit acrylic

LLDPE: polyetylen mch thng, ttrng thp

LLDPE-g-AA: LLDPE ghp axit acrylicLLDPE-g-MA:LLDPE ghp anhydrit maleic

MA: anhydrit maleic

2,6MgSPS: PS cha 2,6% mol sunfonat trung ho magie

MMA: metyl metacrylat

MMA-g-MA: copolyme metylmetacrylat ghp anhydrit maleic

MMA-MAA: copolyme metylmetacrylat-co-axit metacrylic

MMA-POSS: copolyme MMA - oligosilsesquioxan a din

2,6MnSPS: PS cha 2,6% mol sunfonat trung ho mangan

NBR: poly(acrylonitril-co-butadien)

PA: polyamit

PA-g-MMA: PA ghp metyl metacrylat

PBAT: poly(butylen adipat-co-terephtalat)

PBO: 2,2-(1,3-phenylene)-bis-(2-oxazolin)PBT: poly(butylen terephtalat)

PC: polycacbonat

PC-b-PMMA: copolyme khi polycacbonat-polymetyl metacrylat

PCl: poly(-capro lacton)


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Cc tvit tt 9

PDLLGA: poly(D,Llactic-co-axit glucolic)

PDMAEMA: polydimetylaminetylmetacrylat

PEA: poly(etyl acrylat)

PEB: poly(etylen-co-butylen)

PECH: poly(epiclohydrin)

PEG: poly(etylen glycol)

PE-g-AA: polyetylen ghp axit acrylic

PEH: poly(etylen-co-hexen)

PEMA: poly(etyl metacrylat)

PEN: poly(etylen 2,6-naphtalat)PEO: poly(etylen oxit)

PE-PA: copolyme polyetylen-polyamit

PES: poly(ete sunphon)

PET: poly(etylen terephtalat)

PF: nha phenol formaldehyt

PHBV: poly(hydroxybutyrat-co-hydroxyvalerat)

PHMA: poly(n-hexyl metacrylat)

PI: polyizopren

PLA: poly(lactic axit)

PLLA: poly(L-lactic axit)

PMA: poly(metyl acrylat)

PMMA: polymetyl metacrylat

PP: polypropylenPP-g-AA: copolyme PP-g-axit acrylic

PP-g-GMA: PP-g- glyxidyl metacrylat

PP-g-MA: copolyme PP-g-anhydrit maleic

PP-HBP: PP ghp poly(amit este) siu nhnh


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Thi Hong10

PP-MA: copolyme propylen-anhydrit maleic

PPO: poly(2,6-dimetyl-1,4-phenylen oxit)

PS: polystyren

PU: polyuretan

PVA: poly(vinyl axetat-co-vinyl alcol)

PVAx: polyvinyl axetat

PVB: poly(vinyl butyral)

PVC: polyvinyl clorua

PVDF: polyvinyllidenfluorit

SAN: copolyme styren-acrylonitrilSBS: copolyme khi styren-butadien-styren

SEBS: copolyme tribloc styren-b-etylen-co-butylen-b-styren

SEM: hin vi in tqut

STVHP: copolyme styren-co-4-vinylphenol

Tcl: im m

TEGOMER: copolyme tribloc polycaprolacton-

poly(dimetylsiloxan)-

polycaprolacton

TEM: hin vi in ttruyn qua

Tg: nhit thutinh ho

Tm: nhit nng chy

TMA: phn tch cnhit

TPU: polyuretan nhit do

UCST: nhit ho tan ti hn trn

VA: vinyl axetat

2,6ZnSPS: PS cha 2,6% mol sunfonat trung ho km


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11

Li ni u

Polyme blend l mt loi vt liu thp c to thnh t t nhthai homopolyme/copolyme thnh phn. Trn hp hay blend ho ccpolyme/copolyme (nht l t cc polyme v copolyme cthng mi ho) ngy cng phbin chto vt liu polyme mic cc tnh cht, hnh thi cu trc v gi thnh nhmong mun, rhn v tn t thi gian hn so vi trng hp, ng trng hp ccmonome hay ng trng ngng cc hp cht thp phn tmi. Vtliu polyme blend c mt trong hu ht cc lnh vc ca kthut v

i sng nh t, hng khng, ng st, vin thng, xy dng, dtmay, nng nghip, ththao, y t

Cng vi qu trnh cng nghip ha, hin i ha t nc, nhucu v cht do, trong c polyme blend khng ngng tng vcng nghip cht do tr thnh mt ngnh kinh t quan trng,ng gp xng ng vo chin lc xut khu ca t nc. V vy,yu cu vo to cn b c trnh cao trong lnh vc vt liupolyme v polyme blend ngy cng trnn cp thit.

Trn thgii c mt scun sch vit vvt liu polyme thp, trong c polyme blend. l nhng ti liu khoa hc qucho cc cn bnghin cu v trin khai trong lnh vc cht do, vtliu polyme thp nc ta hin nay, cc sch chuyn kho vvt liu polyme blend bng ting Vit cha c. V vy, vit v xutbn sch chuyn kho v vt liu polyme blend l rt cn thit.Cun sch chuyn kho ny c vit trn c s tham kho cccng trnh cng b ca cc tc gitrong v ngoi nc v cckt qunghin cu ca tc gitrong lnh vc vt liu polyme blend.N c sdng lm ti liu ging dy chuyn cho sinh vin,hc vin cao hc trong lnh vc ha hc v cng nghpolyme, hacng ngh, vt liu cao phn tv thp mt sbmn thucKhoa Cng ngh Ha hc, Trng i hc Bch khoa H Ni,Khoa Ha hc, Trng i hc Sphm H Ni v cho hc vincao hc, nghin cu sinh Vin Kthut nhit i, Vin Khoa hcv Cng nghVit Nam. Ngoi trnh by cc khi nim vpolymeblend, s ho trn v s tng hp ca cc polyme, cc dng


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Thi Hong12

polyme blend, cc phng php phbin xc nh stng hp cacc polyme, sch chuyn kho tp trung nu cc phng php chto vt liu polyme blend, cc bin php tng cng stng hpca cc polyme trong polyme blend. y l cskhoa hc v cngnghquan trng chto vt liu polyme blend c cu trc v tnhcht mong mun, gp phn ng dng vt liu polyme blend c chtlng vo cc lnh vc k thut v i sng. Cun sch chuynkho sl ti liu khoa hc v sch tham kho c ch cho bn c lsinh vin, hc vin cao hc, nghin cu sinh, cc cn bk thuthot ng trong lnh vc vt liu polyme, cao su, cht do, vt liucompozit v bn c khc c quan tm

Mc d c nhiu c gng khi vit v bin son cun sch

chuyn kho ny, nhng khng th trnh khi thiu st. Tc girtmong nhn c kin ng gp ca cc ng nghip cng bn cnng cao cht lng v ni dung cun sch. Xin trn trng cmn. Mi kin ng gp, ph bnh xin gi va ch:

Thi Hong

Vin Kthut nhit i, Vin Khoa hc v Cng nghVit Nam,S18 ng Hong Quc Vit, qun Cu Giy, H Ni.

in thoi: (04) 37564265, email: [email protected]

Tc gi


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Mu

Mt trong nhng thnh tu quan trng ca khoa hc v cng nghvt liu trong vi chc nm trli y l nghin cu, chto vng dng c kt qucc vt liu polyme trn hp, polyme thp,trong c vt liu polyme blend. Vt liu ny , ang v scmt trong hu ht cc lnh vc ca i sng v kthut vi cc uth ni tri. Trn hp hay blend ho cc polyme (nht l t ccpolyme v copolyme c thng mi ho) l mt hng rt ctrin vng chto cc vt liu polyme mi, kt hp c nhiutnh cht tt ca cc polyme thnh phn, p ng c cc yu cukthut, rhn v tn t thi gian hn so vi trng hp hay ngtrng hp cc monome mi cng nh ch to copolyme khi,copolyme ghp v copolyme thng k tcc monome thng dng.C thiu chnh mt di kh rng cc tnh cht ca vt liu nhthay i t l cc polyme thnh phn v iu kin ch to thuc vt liu polyme c cc tnh cht mong mun... Tuy nhin, dokhc nhau vcu to, cu trc, phn cc, trng lng phn t,nhit chy mm, chschy, nht chy tng i, khnngho tan trong cc dung mi... nn khi trn hp hu ht cc polyme

khng c khnng ho trn v tng hp vi nhau v to thnh mthc cu trc nhiu pha.

Lm th no nh gi cc polyme c kh nng ho trn,tng hp hon ton, tng hp mt phn hay khng tng hp?Bng skt hp gia nghin cu l thuyt (cc vn vdung dchpolyme, hn hp cc polyme, nhit ng hc cc qu trnh ho tan,gin pha, chuyn pha, chuyn trng thi cc polyme...) v thcnghim trn cc hn hp polyme khc nhau, cc nh khoa hc xut v ng dng nhiu phng php xc nh khnng tng

hp ca cc polyme.Hin nay, trn th gii v Vit Nam ang c nhiu phng

php khc nhau chto polyme blend. Trong , cc phng phpchto polyme blend trong dung dch, trng thi nng chy trncc thit bgia cng cht do, lu ho ng v to cc mng lian xen ca cc polyme c sdng phbin hn c.


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Thi Hong14

Tnh cht v hnh thi, cu trc ca vt liu polyme blend phthuc vo nhiu yu t, c bit l khnng tng tc v trn lnca cc polyme trong h. chto vt liu polyme blend c chtlng cao, mt vn rt quan trng l phi nng cao kh nngho trn v tng hp ca cc polyme, to ra vt liu c hnh thihc pha bn vng, trong pha phn tn vi kch thc ti uphn tn u vo pha lin tc, khng b thay i theo thi gian,khng bnh hng ca cc tc ng bn ngoi. Cng vi sphttrin ca cng nghpolyme v vt liu polyme trn hp, trong thigian qua, cc nh khoa hc v cng ngh nghin cu v tm racc bin php nng cao kh nng ho trn v tng hp ca ccpolyme. y l mt trong nhng vn quan trng nht ca cngnghvt liu polyme blend. Cun sch chuyn kho ny trnh by

mt cch tng i h thng vcc vn lin quan ti vt liupolyme blend nh nhit ng hc cc qu trnh ha tan ccpolyme, s ho trn v tng hp ca cc polyme, cc phngphp nh gi khnng ho trn, tng hp polyme, cc phngphp ch to polyme blend v cc gii php nng cao kh nngho trn v tng hp polyme.


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Chng I

NHNG VN CHUNG CA POLYME BLEND

I.1. Mt skhi nim vpolyme blend

Mc d vt liu polyme blend c nghin cu, ng dng tlunhng hin nay vn cha c mt nh ngha chnh thc vloi vtliu ny. Tnhng nm bn mi ca thkhai mi, nh bc hcP. J. Flory (ngi c gii thng Nobel v ha hc) nghincu v nhit ng hc v cn bng pha trong hn hp polymenhng thut ngpolyme blend vn cha xut hin trong cc cngbkhoa hc ca ng v cc cng s. Vo nhng nm tm mi cathkhai mi, J. F. Rabek l mt trong cc nh khoa hc u tinchnh thc a ra khi nim polyme blend. Theo ng, polyme blend(hay polyblend) l mt hn hp vt l ca 2 hoc nhiu

polyme/copolyme, gia cc polyme/copolyme ny khng c lin ktng ho tr[1]. Theo L. A. Utracki, polyme blend l mt hn hpca t nht 2 polyme hoc copolyme [2]. Theo P. Painter v M.Coleman, polyme blend l mt hn hp ca hai hay nhiu polyme.Vt liu ny c nhng tnh cht mi da trn cc tnh cht ca ccpolyme ban u (polyme c shay polyme thnh phn) [3]. TheoB. M. Rao, P. R. Rao v cng s, polyme blend l mt hn hppolyme, trong c t nht 2% polyme hoc copolyme trong mtpolyme hoc copolyme khc [4]. D. R. Paul v C. B. Bucknall quannim rng polyme blend l mt trng hp c bit ca dung dchcc polyme [5]. W. E. Baker v G. H. Hu cho rng, polyme blend lloi vt liu trn hp c to thnh bi skt hp 2 hoc nhiupolyme khc nhau nhm thomn yu cu sdng no [6].

Nhvy, polyme blend l mt khi nim rt rng, song tcckhi nim v polyme blend nu trn, c th thy polyme blend lmt loi vt liu trn hp hay vt liu thp.Ngoi trn hp cc


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Thi Hong16

polyme c bn cht, cu to, cu trc i phn tkhc nhau, hnhp ca 2 polyme c tng hp tcng mt monome, song c cutrc i phn t khc nhau nh polyetylen mch thng v mchnhnh, polypropylen cu trc ng u lp thv khng ng ulp thcng c xem l polyme blend Mt hn hp polyme tothnh khi trng hp mt monome trong mt polyme khc cng lmt polyme blend. Trong ho hc polyme, c th kt hp haipolyme c cu to ho hc khc nhau thnh mt copolyme nhphn ng gia cc nhm chc cui mch. Nhng copolyme khinh vy c th b phn pha, song chng li c xem l h mtthnh phn. Tng t, nu chc mt phn cc polyme to khi vchyu phn blp bmt phn cch gia hai polyme, khi hto thnh l mt polyme blend. Vt liu lp to thnh t cc loi

polyme khc nhau (mi lp l mt loi polyme thnh phn) cngc gi l polyme blend.

Trong polyme blend, gia cc polyme c thc tng tc vtl hoc tng tc ho hc, c thl hng thhoc dth. Trongpolyme blend ng th, hai polyme thnh phn khng cn c tnhring v tnh cht ca polyme blend thng l trung bnh cng cahai polyme . Trong polyme blend dth, cc tnh cht ca chaipolyme thnh phn hu nhc ginguyn [1-3,6].

Khi nghin cu v hnh thi cu trc pha ca polyme blend,ngi ta cho rng: polyme blend l mt loi vt liu c nhiu pha,trong c mt pha lin tc/pha nn (matrix) v mt hoc nhiupha phn tn (dispersion phase). Mi mt pha c to nn bi mtpolyme thnh phn. Khi sdng nha novolac phenol formaldehytlm cht n tng cng cho cao su, nha novolac nm pha phntn, cn pha lin tc l pha cao su. Tuy nhin, trong thc t tnti mt svt liu polyme blend khng hon ton theo quan nimnhvy, l vt liu polyme blend c 2 pha polyme lin tc xenk nhau (co-continuous two-phase morphology) nh vt liu

polyme blend PVC/NBR, SBR/NBR/polyacrylonitril mt stlthch hp [7-10].

I.2. Nhit ng hc qu trnh ho tan cc polyme

Nghin cu nhit ng hc qu trnh ho tan cc polyme gp phnm tnh lng qu trnh trn cc polyme trong mt h. N c


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Chng I. NHNG VNCHUNG CA POLYME BLEND 17

xy dng da trn csl thuyt nhit ng hc ca cc dung dchthng (dung dch cc hp cht thp phn t). i vi mt hccpolyme cho trc, tcc phng trnh nhit ng hc, c thtnh

ton v thit lp gin pha, hoc tcc gin pha xc nh cbng thc nghim ngi ta c thphn tch, nh gi cc thng sphthuc thnh phn, nhit , thng sho tan... ca cc polyme[11-18]. Phng php thit lp v m t hm nhit ng ca qutrnh trn cc polyme (nng lng t do trn - G) da vo thuytnhit ng hc hin tng c Flory Huggin nghin cu rtchi tit [11]. y l csquan trng nh gi mc ho trn(miscibility) hay tng hp (compatibility) ca cc polyme.

L thuyt Flory - HugginL thuyt Flory - Huggin v nhit ng hc qu trnh trn ccpolyme c xy dng trn csl thuyt nhit ng hc vdungdch cc hp cht thp phn ttrong Ho l i cng. Trong iukin ng nhit, ng tch v ng p, phng trnh nhit ng mtquan hgia bin thin nng lng tdo vi bin thin ni nng,bin thin entropy v nhit ca hc vit nhsau:

G = H - TS (I.1)Trong :

G: bin thin nng lng tdo, H: bin thin ni nng hayentalpy, S: bin thin entropy, T: nhit ca h.

Vn dng l thuyt vdung dch cc hp cht thp phn tkhixy dng phng trnh nhit ng ca dung dch cc polyme, Floryv Huggin chp nhn nhiu githuyt gn ng. Trong , ccmt xch/n vmonome ca cc polyme thnh phn c phn b

ngu nhin trn cc mng c ln bng nhau v bin thinentropy ca hl:

RV A BS = ______( ____ ln A +

____ lnB ) (I.2)

Vr MA MB


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Thi Hong18

Trong :

V: thtch ca h, Vr: thtch ca mt n vmonome, A vB: phn thtch ca polyme A v polyme B tng ng, MAv MB:

khi lng phn t ca polyme A v polyme B tng ng v R:hng skh l tng.

Vi cc polyme thnh phn khng phn cc, tng tc phn tgia cc polyme chyu l lc phn tn, khi ni nng ca hl:

RTV

H = _______A B AB (I.3)Vr

Trong :

AB: thng stng tc phn tgia polyme A v polyme B.

Thay cc biu thc (I.2) v (I.3) vo (I.1), Flory v Huggin ara phng trnh nhit ng hc m tbin thin nng lng tdoca h2 polyme n phn tn nhsau:

RVT A BG = _______( ____ ln A +

____ lnB + A B AB) (I.4)

Vr MA MB

Bng thc nghim, ngi ta c thxy dng gin nhit ngtcc thng s bit v da vo (I.4) tnh thng stng tcphn tABcho mt h2 polyme cho trc. Ngoi ra, c thxcnh ABbng mt sphng php khc nhphng php p sutthm thu, sc k kh... Tuy nhin, mi phng php u c nhnghn chnht nh. c gi trABv nh gi 2 polyme c kh

nng trn ln vi nhau trong mt h, cn vn dng tng quan giacc thng stng tc v thng sho tan:

Vr

AB=___

(A B)2

(I.5)

RT


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Trong :

Av B: thng sho tan ca polyme A v polyme B tng ng.

tnh ABtbiu thc (I.5) cn phi bit thng sho tan cacc polyme. Ni chung, thng sho tan ca cc polyme c xcnh bng thc nghim v c cng b trong nhiu ti liu. Dophng php v iu kin th nghim xc nh thng sho tan cacc polyme khc nhau, nn cc kt qucng bvthng sho tanca cng mt polyme c ssai lch. iu ny dn ti nhng kt qukhng thng nht vgi trca AB. Tuy nhin, vic sdng thngsho tan ca cc polyme cho php nh gi khnng trn ln ccpolyme kh chnh xc. tnh thng sho tan ca polyme ta cbiu thc:

= Fi/M (I.6)

Trong :

: t trng ca polyme nhit cho trc, M: khi lngphn tca monome, Fi: tng cc hng stng tc phn tcacc nhm trong monome.

H polyme blend 3 thnh phn, trong c mt thnh phn

ng vai tr ca cht tng hp ang ngy cng c quan tmnghin cu. Khi cc thnh phn ca hny l n phn tn, phngtrnh nhit ng hc ca qu trnh trn hp 3 thnh phn c dng:

RVT A B CG = _______(____ lnA +

____lnB )+

____ln

Vr MA MB MC(I.7)

Trong :C: phn th tch ca polyme C, MC: khi lng phn t ca

polyme C, BC: thng s tng tc phn t gia polyme B vpolyme C, AC: thng s tng tc phn t gia polyme A vpolyme C.

C+ABAB+BCBC+ACAC)


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Thi Hong20

Cc kt qu nghin cu thc nghim lin quan ti polymeblend 3 thnh phn trn c s polyetylmetacrylat (PEMA),polymetylmetacrylat (PMMA) v polyvinyllidenfluorit) (PVDF)

kh ph hp vi kt qutnh ton l thuyt theo phng trnh (I.7).Hin nay, cc sliu nhit ng ca cc polyme blend 3 thnh phnc cng brt hn chv cha c phng php nh gi nhanhkhnng ha trn ca cc polyme trong h.

Nh vy, trong qu trnh xy dng l thuyt nhit ng hchin tng, Flory - Huggin s dng m hnh mng tnhentropy ca h, cc tc gi phi chp nhn mt sgithuyt gnng. Cc phng trnh nhit ng hc I.4 v I.7 khng th vndng c cho h cc polyme c cc v c cc tng tc mnh,ng thi n cng bqua hiu ng gy ra bi phn th tch tdotrong h. Mt khc, l thuyt ny ch xy dng trn c s ccpolyme trong h l n phn tn m trong thc t, phn ln ccpolyme tng hp c u dng a phn tn. V nhng hn chny nn trong mt strng hp, c ssai khc vkt qugiagin nhit ng xc nh bng thc nghim v tnh ton theo lthuyt. Mt c trng nhit ng thng hay gp cc dung dchpolyme v polyme blend m t xut hin hn cc dung dch thpphn t, l qu trnh tch pha khi nhit ca htng ln. Hintng ny cha thgii thch c bng l thuyt nhit ng hc

ca Flory - Huggin. Tuy c nhng hn chsong l thuyt Flory -Huggin vn l mt trong nhng csl thuyt quan trng vnhitng hc qu trnh trn hp cc polyme. khc phc nhng hnchnu trn, trong nhng nm qua, mt stc gi pht trin vm rng l thuyt Flory - Huggin cho hcc polyme a phn tn,trong c lu n phn thtch tdo, sti nh hng ca cci phn tpolyme trong hn hp cc polyme [19, 20].

Sho trn, stng hp ca cc polyme trong polyme blend

nh gi mc trn hp cc polyme, ngi ta a ra cc khinim v kh nng ho trn (miscibility) v kh nng tng hp(compatibility) cc polyme. Khnng ho trn cc polyme thhinstrn hp cc polyme mc phn tv to thnh hvt liupolyme ng th, mt pha [1, 2]. Khi , mc phn tn ca mtpolyme trong polyme nn t kch thc phn t hay kch thcnanomet. Nhiu tnh cht quan trng v u im ni tri capolyme blend lin quan vi c tnh ny ca h. Khi cc polyme


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thnh phn khng c khnng trn hp vmt nhit ng, hccpolyme stch pha.

Khnng tng hp ca cc polyme thhin khnng trn ccpolyme vo nhau bng mt bin php kthut/cng nghno to thnh mt hvt liu polyme mi p ng cc yu cu ra nhtng cng cc tnh cht cl, tnh cht in mi, bn nhit, bn in, bn dung mi... [2, 5, 6]. Thc t c nhiu polymekhng c kh nng trn hp v mt nhit ng (khng ha trn)nhng polyme blend ca chng vn c tnh cht cl, bn nhit, bn in tt, tc l cc polyme thnh phn c kh nng tnghp tt, p ng c cc yu cu sdng nht nh.

Sho trn v stng hp cc polyme lin quan cht chtinhit ng hc qu trnh trn v ho tan cc polyme nh cp trn. Cng ging nhtrn ln cc cht lng thp phn t, qu trnhtrn ln cc polyme thng l qu trnh thu nhit. Vmt ho hc,skhng tng hp ca cc polyme khng tng tnhau vmtcu to, cu trc, khi lng phn t, thng stan... dng nhlmt quy lut v sho trn cc polyme to thnh mt hn hp ngth (nh dung dch thc mt pha) ch l trng hp ngoi l. Sngoi lny chc thxy ra vi cc polyme phn cc, polyme nyc tng tc c bit vi polyme kia. Vmt nhit ng hc, cc

polyme ho trn vi nhau khi bin thin nng lng tdo (khi trnchng vi nhau) mang gi trm:

GM= HM- T. SM < 0 (I.8)

v o hm ring bc 2 ca bin thin nng lng tdo theo tlth tch ca polyme th hai trong hn hp polyme mang gi trdng:

2

GM/22

> 0 mi tl (I.9)

Trong :

HM- bin thin entalpi (nhit trn ln) khi trn 2 polyme

SM -bin thin entropy (ch mc mt trt t) khi trn 2polyme


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Thi Hong22

Ngha l, khi trn 2 polyme vi nhau, nng lng t do qutrnh trn Gtr gim nu qu trnh to nhit (HM < 0) v tngentropy trn SM. Trong trng hp entropy trn SMkhng ng

k, bin thin nng lng tdo qu trnh trn

GM< 0 nu nhittrn ln HM < 0. Theo l thuyt Flory - Huggin cin, quan hgia GMvi thng stng tc phn tgia cc polyme v thnhphn cc polyme nhsau:

GM/RTV = ABAB (I.10)

Theo (I.10), 2 polyme chho trn v tng hp hon ton khi

thng stng tc phn tAB< 0. Hai polyme polyetylen oxit vpolymetylmetacrylat ho trn hon ton do c ABbng - 0,35.

Trn thc t, s thay i GM trong qu trnh hnh thnh hnhp l tng ca cc polyme, c xc nh chyu qua i lngHM. i lng ny lin quan ti skhc nhau gia mt nnglng kt dnh (cohesive energy density) ca cc polyme:

HM= [VA(A- B)2(1- A)

2]1/2

(I.11)

Trong :

VAv A: thtch v phn thtch ca thnh phn polyme Atrong hn hp polyme.

Av B: thng stan ca polyme A v polyme B.

T phng trnh (I.10), c th nh gi kh nng hotrn/tng hp ca 2 polyme hoc cp dung mi - polyme nu bitcc thng sho tan tng ng vi 2 polyme hoc thng sho tanca cp dung mi - polyme (bng I.1) [21, 22]:


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Bng I.1. Thng sho tan ca mt sdung mi v polyme [22].

Dung mi

Thng s

ho tan(MPa1/2)

Polyme

Thng s

ho tan(MPa1/2)

Nc 23,4 Polyetylen 7,9 - 8,1

Formamit 19,2 Cao su etylen-

propylen

7,9

Glyxerin 16,5 Cao su butyl 7,9

Anhydrit

sucxinic

15,4 Polyizopren 8,1

Etylen cacbonat 14,5 Polybutadien 8,4

Metanol 14,5 Polystyren 8,6 - 9,1

Dimetyl sulfoxit 13,4 Cao su butadien -

nitril

9,4 - 10,3

Caprolactam 12,7 Polycloropren 8,8 9,2

Pyridin 10,7 Poly(vinylpyridin -butadien)

9,5

Acrylonitril 10,5 Polybutadien-

maleat

9,6 10,6

Axeton 10,0 Polyetylen-

terephtalat

10,7

Toluen 8,9 Nylon6,6 13,6

Hexan 7,3 Polyvinylclorua 9,6

Toluilen -

diizoxianat

11,6 Polyuretan 9,5 10,0

Epiclohydrin 11,0 Nha-amino,epoxy, phenoxy

8,5 14,0

Khi trn cc polyme, nu gi trHM cng nh, cc polymecng c khnng ho trn v tng hp. Nhvy, 2 polyme trn


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Thi Hong24

ln tt vi nhau, qu trnh trn phi l qu trnh tonhit, i hi ctng tc c bit gia cc polyme thnh phn.Cc tng tc nyc th l cc tng tc ho hc (to thnh lin kt ho tr) hoctng tc khng to thnh lin kt ho hc nh lin kt hydro,tng tc ion-ion, tng tc ion-dipol, tng tc lng cc (dipol-dipol) v tng tc cho-nhn [23].

Qu trnh trn cc polyme ph thuc mnh vo nhit . Ccpolyme trn hp tt nhit thp c thkhng cn trn hp tt nhit cao hn, v dtrong qu trnh gia cng.

Trn hnh I.1 l nh quang hc khuch i ca mng polymeblend PS/poly(vinyl metyl ete) (20/80, pkl/pkl) vi cc chiu dy vnhit khc nhau. R rng l mng polyme blend c hnh thi hc

tcc git phn tn (137o

C) sang 2 pha ng lin tc (131 v126oC) v ng th(124oC) [24].

Hnh I.1. nh quang hc khuch i ca mng polyme blendPS/poly(vinyl metyl ete) (20/80, pkl/pkl) cc nhit khc nhau [24].

I.3. Gin pha v chuyn pha ca hn hp cc polyme

Mt hn hp polyme hay polyme blend trng thi cn bng khinng lng tdo ca qu trnh trn cc polyme t gi trcc tiutrong nhng iu kin cho trc no . iu ny c ngha l mthn hp ng th cc thnh phn polyme nm trng thi bnvng, khi nng lng tdo (GM) ca n thp hn tng nng lngtdo ca cc thnh phn (GK) trng thi bit lp:

GM= GM- GK < 0 (I.12)


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Nhvy, 2 hn hp polyme c tlcc thnh phn khc nhaucng c thtn ti bn nhau. Khi , nng lng tdo GM l tngca cc GMca chai pha. i vi mt hn hp cc polyme, bin

thin nng lng tdo GM l hm ca nhit v t l ca ccpolyme thnh phn (hnh I.2). Trong trng hp ny, cc polymethnh phn tch ra khi nhau nhit T1, trong khi nhit T3, h lun bn vng ti tt c cc nng khc nhau ca ccpolyme thnh phn. Ngc li, nhit T2, khi phn thtch capolyme A trong khong A

1n A

2, hsphn thnh hai pha c

phn thtch ca polyme A trong mi pha l A1

v A2. Cc hn

hp polyme lun trng thi bn khi phn th tch ca polyme Anm ngoi khong A

1 v A2. Hai tip im ca ng tip tuyn

chung vi thhm GM theo A l hai im A1

v A2

. Biudin nhit theo phn th tch A1

v A2

tng ng thu cng "binodal" trong gin pha ca h. Cc hn hp polyme cphn th tch nm pha trong ng "binodal" s khng c khnng tn ti vmt nhit ng, l vng hon ton khng hotan ca cc polyme, tc l GM> 0. Vng ngoi l vng ho tanln nhau khng hn chca cc polyme, tng ng vi thnh phnv nhit GM< 0. Vthim un ca cc ng GMln gin pha thu c ng "spinodal". Cc hn hp polymec phn th tch nm trong ng "spinodal" khng bn v sb

tch pha. Ngc li, cc hn hp polyme c phn th tch nmgia ng "spinodal" v "binodal" c th tn ti v c gi lcc hn hp gi bn. Cc hny ch tch pha khi c hot hobi s to mm/to tm pht trin pha. Trong vng gi bn, chcn mt s thay i nh v nng , s tch cc pha polyme sxy ra. ng "spinodal" v "binodal" gp nhau ti im ti hn(critical point), c trng bi nhit ho tan ti hn Tcv phnthtch ti hn Ac.

Bng thc nghim, ngi ta c th xc nh c ng

binodal v spinodal ca h cc polyme. ng binodal lng c trng quan trng ca h, vl thuyt, rt kh c thtnhton xc nh c ng ny. Trong khi , ng spinodalc thxc nh c mt cch kh n gin v n gin nht l xcnh im ti hn v cc thng sc lin quan ca h.


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Thi Hong26

Hnh I.2. Gin pha hn hp polyme/polyme blend.a) Gin nng lng tdo theo phn thtch ca polyme cc

nhit khc nhau. b) ng binodal v spinodalca hn hp polyme.

trng thi binodal, ho thca cng mt polyme cc phatrong hphi bng nhau. i vi h2 polyme ta c:

GM GM_______

=_______

(I.13)

A1

A2


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GM GM_______ = _______ (I.14)

B1

B2

S dng phng trnh (I.4) ca Flory - Huggin, t (I.13) v(I.14) c thrt ra hphng trnh m tcc i lng c trngca h trng thi binodal. Trng thi spinodal ca hcc trng bi iu kin l vi phn bc hai ca hm GMtheo tlthnh phn phi bng khng:

2

GM_______ = 0 (I.15)2A

T(I.4) rt ra:

(AB)sp= [1/MA(A)sp+ 1/MB(B)sp].1/2 (I.16)

Trong :

(AB)sp: thng s tng tc gia polyme A v B trng thispinodal

(A)sp v (B)sp: phn th tch ca polyme A v polyme B trng thi spinodal

iu kin ti hn c thomn khi vi phn bc hai v bc baca GMtheo u bng khng, ta c:

2GM 3GM

________=

________ = 0 (I.17)

2A

3A

Tphng trnh (I.4) v theo (I.17) ta rt ra cc iu kin tihn sau:

1 1 2

(AB)cr= (1/2) + (I.18)(MA)

1/2 (MB)

1/2


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Thi Hong28

(MB)1/2

(A)cr= (I.19)(MA)

1/2+ (MB)

1/2

(MA)1/2

(b)cr= (I.20)(MA)

1/2+ (MB)1/2

Trong :

(AB)cr: thng stng tc gia polyme A v polyme B

(A)crv (b)cr: phn thtch ca cc polyme A v polyme B

tng ng iu kin ti hn.nh gi kh nng ho trn/tng hp ca hai polyme,

cn so snh phng trnh (I.5) vi (I.18). Nu AB > (AB)cr, 2polyme c kh nng trn hp mt s t l thnh phn nhtnh. Khi chnh lch gia ABv (AB)crcng ln, khong tlthnh phn m 2 polyme c kh nng trn hp cng b.Vi mt t lthnh phn nht nh, liu 2 polyme c khnngtrn hp hay khng, cn so snh phng trnh (I.5) vi (I.16).Nu AB(AB)sp, 2 polyme khng c khnng trn ln.

Khnng trn ln v ho tan cc polyme vi nhau rt hnchv phthuc vo nhiu yu tnhkhi lng phn t, cuto, cu trc, phn cc, thng s tan ca polyme... Nhit ng vai tr quan trng trong cn bng pha lng - lng. Nhiuhn hp cc hp cht thp phn thoc cc cp polyme khngtrn ln vi nhau trthnh trn ln tt khi un nng. Ngc li,c nhiu hn hp cc hp cht thp phn t hoc cp polymetrn ln tt sbtch pha khi un nng [25]. Nhit (T) xy ra qu trnh tch pha ca hn hp v l mt hm ca thnh

phn () vi nhit tch pha thp nht gi l nhit ho tanti hn di (lower critical solution temperature, LCST). Nm pha trn ng ny, hai polyme khng trn ln nhau (tch pha)v pha di ng ny hai polyme trn ln tt vi nhauthnh mt pha. Bng thc nghim, ngi ta xc nh hn hppolyme c hiu ng nhit trn ln m (to nhit) c gi trLCST. Nhit ho tan ti hn di c th iu chnh bng


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cch thay i khi lng phn t trung bnh ca cc polyme vtlthnh phn cc polyme. Hn hp polyme c hiu ng nhittrn ln dng skhng c gi trLCST, m chc nhit ho

tan ti hn trn (upper critical solution temperature, UCST).Nm pha di ng UCST, 2 polyme khng trn ln vinhau v khi tng nhit , vng pha trn ng UCST, 2polyme ho trn tt vo nhau [2, 5, 20, 26, 27].

Trong thc t, c kh nng tn ti nhiu loi gin phakhc nhau ca cc hn hp polyme (hnh I.3). l cc h cnhit ho tan ti hn trn (UCST), nhit ho tan ti hndi (LCST), c ng thi c UCST v LCST v khng cnhit ho tan ti hn [2, 3, 5, 6, 10, 19, 20, 26, 28-35]. Hn

hp polyme c UCST (I.3a) thng c trng cho polyme blendca cc oligome c thng s tng tc ABmang gi trdng.Gin pha ny t tn ti polyme blend vi cc polyme ckhi lng phn t trung bnh ln. Tuy nhin, gin pha nythng gp polyme blend ca mt s copolyme. Hn hppolyme c LCST (I.3b) thng c trng cho polyme blend cacc homopolyme c khi lng phn t trung bnh ln. HnhI.3c l gin pha ca hn hp polyme c mt LCST nm trnmt UCST. Gin ny thng xut hin vi dung dch polyme

khi m LCST lun xut hi

n

trn nhit

si c

a dung mi.Hnh I.3d l gin pha ca polyme blend vi UCST nm trnLCST v to thnh mt vng trn khp kn. Hnh I.3e l gin pha ca polyme blend vi UCST hp nht vi LCST to thnhmt gin pha khng c vng nhit tn ti mt pha trongton bdi thnh phn hn hp polyme. c bit, khi mt tronghai polyme thnh phn l a phn tn th c th tn ti dnggin pha c nhiu UCST (I.3f) v nhiu LCST (I.3g).


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Thi Hong30

Hnh I.3. M tcc loi gin pha ca polyme blend

(a) c 1 UCST, (b) c 1 LCST, (c, d) c ng thi 1 UCST v 1 LCST,(e) khng c nhit ho tan ti hn, (f) c 2 UCST, (g) c 2 LCST.

Hnh I.4 minh ha mt trong cc loi gin pha ca polymeblend - gin pha ca hn hp poly(etylen-co-hexen) vpoly(etylen-co-butylen) (PEH/PEB, PEH l polyme kt tinh, PEB lpolyme v nh hnh). Trong gin ny, xut hin gi trUCST


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146oC v t l PEH 0,44 (pkl). Nh vy, polyme blend PEH/PEB

khng c kh nng tng hp. Cc ng cong binodal vspinodal tnh ton v c vtrn gin l cc ng nt lin

m (TS) v nt t tng ng. ng gm cc hnh vung mutrng biu hin nhit nng chy cn bng (equilibrium meltingtemperature) (Tm) ca PEH trong polyme blend PEH/PEB [36].

Hnh I.4. Gin pha ca polyme blend poly(etylen-co-hexen)/poly(etylen-co-butylen) (PEH/PEB). ng cong binodal vspinodal: ng nt lin m v nt t tng ng. ng gm cc

hnh vung mu trng: nhit nng chy cn bng [36].

Chuyn pha trong hn hp 2 polyme

Trn hnh I.5 l gin trnh by schuyn pha ca mt hn hp 2polyme c trn vi nhau. Nu c2 polyme c cu trc v nh

hnh, nhit thutinh ho (Tg) thay i n iu theo thnh phnpolyme. Nu mt polyme c cu trc kt tinh, nhit chy sgimnh v polyme ny b pha long bi polyme kia. Ngi ta ginh, pha v nh hnh tn ti l mt hn hp ng th. N sgingnhcao su nhit ln hn Tgv trthnh thutinh nhit nhhn Tg.


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3. Polyme blend khng ho trn v khng tng hp: hnh thipha ca 2 polyme rt th, ng knh pha phn tn ln, khng u,ranh gii phn chia pha r rng, bm dnh bmt 2 pha rt ti, c 2

Tgring bit ng vi Tgca 2 polyme ban u.

I.5. Slc lch spht trin v ng dng ca polyme blend

Slc lch spht trin ca polyme blend

Polyme blend c sdng trong i sng v kthut tlusong tng u tin vthp cc polyme thuc vThomasHancock khi ng trn hp cao su thin nhin v gutta percha ch to mt hn hp cc hp cht cao phn t dng lm vi

chng thm nc. S pht trin nhanh chng ca polyvinylclorua (PVC) v copolyme butadien - acrylonitril (NBR) toiu kin cho polyme blend PVC/NBR xm nhp thtrng vonm 1942. Cng nm , polyme blend mng li cc polymean xen (interprenetrating polymer networks - IPN) ca styrenv butadien (tn thng mi l Styralloy-22) ra i. Vonhng nm 1950, nhpht minh ra polypropylen (PP) iu holp thm Cng ty Phillips Petroleum ch to polyme blendca PP vi polyetylen (PE) nhm tng cng bn va p nhit thp ca PP. Trong nhng nm 1960, polyme blend trn csetylen - propylen - dien (EPDM) v mt spolyme nhit do nhPP, polyamit (PA) c thng mi ho. Trong nhng nm1970, mt lot polyme blend trn c s etylen - propylen-dien/polyolefin,-polyetylenterephtalat/polybutylenterephtalat

(PET/PBT), polycacbonat/nha acrylonitril butadien styren(PC/ABS) c ng dng lm cc chi tit t, xe my, dng cth thao Trong nhng nm 1980, polyme blend t cc polymetnh nng cao (high performance) v PA c ch to v a vong dng thc t, trong c polyme blend PA/polyete-b-amit

(PEBA) (tn thng mi l Rilsan) c dng lm lp phdng bt (powder coating) rt tin li. Trong nhng nm 1990,Tp on Bayer pht trin mnh cc polyme blend trn csPC+ ABS, PC + PA, PA6+PA66 vi cc tn thng mi Bayblendv Cycoloy [39]. Nhng du mc lch spht trin ca polymeblend c trnh by trong bng I.2.


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Thi Hong34

Bng I.2. Nhng du mc lch spht trin ca polyme blend [2].

Nm Skin

1846 Thomas Hancock cng bpht minh u tin vpolymeblend trn cscao su thin nhin v gutta percha

1942 Cng bpht minh u tin vpolyme blend nhit dotrn c sPVC v NBR; Cng ty Dow. Chem. thngmi ho polyme blend IPN (interprenetrating polymernetworks - mng li cc polyme an xen) ca styren vbutadien (tn thng mi l Styralloy-22)

1946 Pht trin nha acrylonitril butadien styren (ABS) l hnhp c hc ca NBR vi poly(styren-co-acrylonitril)(SAN)

1947 Nghin cu sho trn v tng hp ca 35 cp polyme,c 3 cp ho trn hon ton l nitroxellulo vipolyvinylaxetat (PVAc) hoc polymetylmetacrylat(PMMA) v benzylxellulo vi polystyren (PS)

1951 Pht minh polypropylen (PP) iu ho lp th, tngcng bn va p nhit thp ca n bng cch

trn hp vi polyetylen (PE)1960 Pht hin khnng trn hp ca PS vi polyphenylen ete

(PPE), hblend Noryl PS/PPE c thng mi ho

1962 Cc loi cao su etylen-propylen (EPR) v etylen propylen-dien (EPDM) c thng mi ho v sdngnng cao bn va p cho polyme nhit do; chtopolyme blend ca ABS vi poly (-metylstyren-co-acrylonitril) (ABS c bn nhit cao)

1969 Cc polyme blend ca ABS/PVC v PP/EPDM cthng mi ho vi cc tn thng mi l Cycovin vSantopren

1975 Cng ty DuPont ch to nylon siu dai tpolyetylenterephtalat (PET) c bsung mt lng nhcht n hi polyolefin


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1976 Pht trin polyme blend PET/polybutylenterephtalat(PBT) (seri Valox 800)

1977 Pht trin polyme blend trn cspolycacbonat (PC) vABS vi cc tn thng mi l Bayblend v Cycoloy

1979 Pht trin polyme blend trn c s PC bin tnh bngPBT hoc PET vi tn thng mi l Xenoy

1980 Ch to polyme blend dai ca cao su vi PBT (tnthng mi l Celanex 500) v polyoxymetylen (POM)(tn thng mi l Celcon C-400); polyme blend caABS vi polysulfon (PSO) (tn thng mi l Arylon-T)

1981 Ch to polyme blend ca poly (styren-co-maleicanhydrit) (SMA) vi ABS (tn thng mi l Cadon) vPC (tn thng mi l Arloy); polyme blend PPE/PS (tnthng mi l Prevex)

1982 Selar c sdng bin tnh v tng khnng tnghp ca polyamit (PA) v nh hnh v polyolefin

1983 Chto polyme blend ca PPE vi PA, mra hpolymeblend tnh nng cao (high performance) vi tn thngmi l Noryl plus; Cng ty ATOCHEM a vo thtrng 2 polyme blend c cha polyete-b-amit (PEBA)l PBT/etylen vinylaxetat copolyme (EVA)/PEBA (tn

thng mi l Organter) v PA/PEBA (tn thng mi lRilsan) dng lm lp phdng bt (powder coating)

1984 Pht trin polyme blend ca polyuretan (PU) vi PC (tnthng mi l Texin); polyme blend ABS/PA (tnthng mi l Elemid); polyme blend PC/PBT/cht nhi (tn thng mi l Macroblend) sdng trong cngnghip t

1985 Ch to polyme blend ca PC vi poly(acrylat-co-styren-co-acrylonitril) (ASA) (tn thng mi lTerblend-S)

1986

-

1996

Pht trin polyme blend PC/ABS cht lng cao (tnthng mi l Pulse v Bayblend) ch to ni tht t, dng cththao


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Thi Hong36

Mt sng dng ca polyme blend

Hnh I.6. Mt schi tit ca xe my 3 bnh (a) chto tpolymeblend PC/PET (b, c) [40].

Theo c tnh ca cc chuyn gia, tng sn lng polymeblend ca thgii khong 1,5 triu tn/nm v hng nm stng 8 -10% [23]. Vt liu polyme blend c ng dng rng ri trongnhiu lnh vc khc nhau ca i sng v kthut: polyme blend tPVC v PE clo ho (CPE, ng vai tr ca cht trgia cng v tngbn va p) c dng lm ng nha cng cp, thot nc, ngbo vcp in thoi, cp quang... N c u im l rt bn cl,bn ho cht, chu thi tit, gi thnh rhn so vi cc ng thp vthp hp kim. Vt liu polyme blend tPVC vi polyuretan (PU)v NBR c dng nhiu trong cng nghip giy da, c bit ldng chto giy da, giy ththao. Vt liu ny nh, nhi, t bmi mn, dsn, v, trang tr... Vt liu cch in polymeblend tEPDM v PE khu mch (XLPE) dng sn xut vdyv cp in lc. N c bn in, bn nhit, bn ho cht v


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bn thi tit cao, c bit l khnng chu lnh rt tt. Mt snhanhit do kthut ca tp on Bayer AG - Cng ho lin bang cl cc vt liu polyme blend trn csPC + ABS (tn thng mi

Bayblend), PC + PA (tn thng mi Triax) [39] v PC + PET [40].Cc vt liu ny c sdng gia cng cc chi tit thay thkimloi trong t v xe my, dng cththao... c im ni bt cacc vt liu ny l bn va p nhit thp, mi mn nh, bnnn, bn nhit cao... Trn hnh I.6 l mt schi tit ca xe my 3bnh chto tpolyme blend PC/PET [40]. Vt liu polyme blendtPVC v lp phacrylic c sdng sn xut cc thanhprofile, ca nha. Trong , lp phacrylic bmt c tc dngchng try sc cho nn nha PVC.

Hoa K, Cng ha Lin bang c l cc nc sdng v cungcp polyme blend nhiu nht trn thgii. Trong bng I.3 l cc nhcung cp polyme blend trn csmt snha kthut v cht nhi Hoa K[2].

Bng I.3. Cc nh cung cp polyme blend trn csmt snha kthut v cht n hi Hoa K[2].

Nh cung

cp

Nha kthut

cs

Polyme blend

Allied Polyamit Polyamit/cht n hi

ARCO SMA Polycacbonat/SMA

Amoco

Chem.

Polysulfon

Polyarylat

Polysulfon/ABS,

Polysulfon/PET

Polyarylat/polyeste

Borg-

Warner

ABS ABS/polycacbonat

Polyphenyl ete/polystyren

Celanese Axetal

Polyamit

PBT

Axetal/cht n hi

Polyamit/cht n hi

PBT/PET, PBT/cht n hi

Dow Chem. ABS Polycacbonat/ABS, TPU/ABS


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Thi Hong38

Co. Polycacbonat

Du Pont Axetal

Polyamit

PET

Axetal/cht n hi

Polyamit/cht n hiPolyamit/polypropylen

PET/cht n hi

Emser Polyamit Polyamit/cht n hi

GAF PBT PBT/PET, PBT/cht n hi

General

Electric

PBT

Polycacbonat

Polyphenylen-

ete

Copolyeste - chtn hi

Polyeteimit

PBT/PET, PBT/cht n hi

Polycacbonat/polyetylen

Polycacbonat/PBT

Polyphenylen-ete/polystyren

Polycacbonat/copolyeste - chtn hi

Polyeteimit/nha nhit do

Mobay Polycacbonat Polycacbonat/ABS,

Polycacbonat/polyetylen

Polycacbonat/PET

Nycoa Polyamit Polyamit/cht n hi

LNP - Polyamit/cht n hi

Thermofil - Polycacbonat/PET

Wilson-

Fiberfil

- Polyamit/cht n hi

Trong khong vi chc nm trli y, ngi ta pht trinmnh vt liu polyme blend trn cscc polyme c khnng bphn hubi sinh vt (vi khun, nm mc, to, enzym...). Cc loivt liu tiu biu l: PE bin tnh tinh bt, tinh bt nhit do/PCLvi tn thng mi Mater - Bi ca hng Novamont (Italia) hay tinhbt nhit do/PCL hoc polyhydrobutyrat-co-valerat vi tn


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thng mi Bioplast ca hng Biotec-Germany (c). Chngc s dng rng ri trong cc lnh vc y - sinh hc v nngnghip nh lm mng ph t hu (che sng gi cho cy trng,

gim cho t), bu m cy ging, ti v cc dng cng thcphm dng mt ln...

Ti Vit Nam, mc d cha c sliu thng k y v chnhthc song vt liu polyme blend ngy cng c ng dng rng ritrong nhiu lnh vc nhckh, giao thng vn ti, xy dng, dtmay... V d, polyme blend CSTN/PE dng chto cc loi mchng va p tu, thuyn cho ngnh ng thu, cc loi sut sitrong ngnh dt may [41 - 45]. Polyme blend PVC/NBR dng chto m cao su - nha cho ngnh ng st. Mt skeo dn cao

su - kim loi trn c s cao su nitril - nha PF c s dngtrong mt slnh vc kthut v dn dng. Mt svt liu polymeblend tcc cc nha nhit do nhPE/PA/PE-g-MA, PE/PA/PE-g-AA v PP/PA/PP-g-MA c sdng chto cc phkinn hi cho t vt b tng ng st (cc loi cn nha v coray).Cc sn phm trn c cung cp cho cc cng ty, x nghipthuc Tng Cng ty ng st Vit Nam, m bo cht lng cangnh, gp phn thay th hng nhp khu. Trn hnh I.7 l snphm cn nha tpolyme blend PE/PA ang c lp t trn cc

tuyn

ng st

n

c ta [46].

Hnh I.7. Sn phm cn nha tpolyme blend PE/PA(mu trng) ang c lp t trn cc tuyn ng st nc ta [46].


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Thi Hong40

Ti liu tham kho

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7. Thi Hong, Nguyn Phi Trung, V Minh c, Ch to vnghin cu tnh cht ca vt liu blend trn c s polyvinylclorua v butadiene-acrylonitrile copolyme, Tp ch Ho hc,

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8. F. Prochazka, C. Carrot, M. Castro, C. Celle, J. C. Majeste,Phase inversion and cocontinuity in immiscible polymer blends,

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9. N. A. Darwish, A. B. Shehata, A. A. El-Megeed, S. F. Halim, A.Mounir, Compatibilization of SBR/NBR blends using

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11. P. J. Flory, Principles of Polymer Chemistry, Cornell UniversityPress, New York (1953).


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12. F. Rodriguez, Principles of Polymer Systems, New York (1996).

13. A. Ravve, Principles of Polymer Chemistry, New York (1995).

14. Bernd - J. Jungnickel, Polymer Blends, Carl Hanser VerlagMuenchen Wien, (1990).

15. O. Olabisi, L. M. Robeson, M. T. Shaw, Polymer - PolymerMiscibility, Academic Press, New York (1979).

16. A. A. Strepikheep, V. A. Derevitskaia, G. L. Slonhimxki, Csca ho hc cc hp cht cao phn t, (dch tting Nga), NXBKHKT, H Ni (1977).

17. J. Brandrup, E. H. Immergut, Polymer Handbook, Sud ed. Wiley

(Interscience), New York (1975).

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19. F. Case, Formulation issues: Predicting polymer miscibility,ANTEC, 2407-2411 (1999).

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calculations of polymer-polymer mixtures, J. Appl. Polym. Sci .,

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Physics, Vol. 41, 2296-2301 (2002).

22. Solubility parameters of solvents and polymer (Hilderbrands),http://www.sartomer.com

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compatibilization of polymer blend, Prog. Polym. Sci., Vol. 23,707-757 (1998).

24. J. C. Meredith, A. Karim, E. J. Amis, High-throughputmeasurement of polymer blend phase behavior, Macromolecules,

Vol. 33, 5760-5762 (2000).

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Thi Hong42

26. H. Wang, K. Shimizu, E. hobbie, Z. G. Wang, J. C. Meredith, A.Karim, E. J. Amis, B. S. Hsiao, E. T. Hsieh, C. C. Han, Phase

diagram of a nearly isorefractive polyolefin blend,

Macromolecules, Vol. 35, 1072-1078 (2002).

27. Muller, Phase-behavior and chain conformations in polymeblends: Monte Carlo simulation vs Mean field theory, Neumann

Institute for Computing Series, Vol. 23, 237-274 (2004).

28. V. Pipich, Ordering transition and critical phenomena in a threecomponent polymer mixture of A/B homopolymers and a A-B

diblockcopolymer, Ph. D dissertation, Ucraine, 13-15 (2003).

29. H. Y. Chen, S. P. Chum, A. Hiltner, E. Baer, Phase behavior ofpartially miscible ethylene-styrene copolymer blends,


30. C. H. Stephen, A. Hiltner, E. Baer, Phase behavior of partiallymiscible blends of linear and branched polyethylens,


31. B. Z. Newby, K. Wakabayashi, R. J. Composto, Confinementinduced stabilization in polymer blend thin films, Polymer, Vol.

42, 9155-9162 (2001).

32. L. H. Sperling, Phase-separation - Block copolymes,

http://www.polyacs.org/ nomcl/pmse.phasesep.html

33. G. D. Merfeld, G. W. Yeager, H. S. Chao, N. Singh, Phasebehavior and morphology of poly(phenylene ether) epoxy

blends, Technical information series, GE Research &

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34. A. P. Smith, R. J. Spontak, C. C. Koch, S. D. Smith, H. Ade,Temperature-induced morphological evolution in polymer blends

procuced by cryogenic mechanical alloying, Macromol. Mater.

Eng., Vol. 274, 1-12 (2000).

35. Nguyn Phi Trung, Nghin cu chto v kho st tnh cht chuoxy ho nhit ca blend polyvinylclorua/cao su butadien-acrylonitril v polyvinylclorua/cao su butadien-acrylonitril/cao

su thin nhin, Lun n tin sHo hc, H Ni (2002).

36. Z. Wang, H. Wang, K. Shimizu, J. Y. Dong, B. S. Hsiao, C. C.Han, Structural and morphological development in

poly(ethylene-co-hexene) and poly(ethylene-co-butylene) blends


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due to the competition between liquid-liquid separation and

crystallization, Polymer, Vol. 46, 2675-2684 (2005).

37. Miscible polymer blend,

http://www.psrc.usm.edu/macrog/blend.htm

38. Polymer blends, http://www.ch.ic.ac.uk/law/blends.html

39. Bayblend, The technical seminarr Bayer EngineeringThermoplastics, Hanoi, 26thAugust (1997).

40. W. F. Smith, Principles of Materials Science and Engineering,International Edition, New York (1996).

41. Nguyn Quang, Bo co tng kt d n SX-TN cp Nh nc

Hon thin cng nghv sn xut m chng va p tu bin tvt liu compozit trn nn cao su thin nhin, m s KHCN-3.DA4, H Ni, (2002).

42. Nguyen Quang, Do Quang Khang, Tran Thi Thanh Van,Application of polymer blends based on the natural rubber/PE in

the buffers for anticollision of ships, Report in Technomer in TU

Chemnitz, Germany, november/2003, 1-8 (2003).

43. Nguyn Quang, Phm Thy Hng, Trnh Vn Thnh, Nghin cunh hng cng ngh v t l thnh phn n tnh cht ca vt

liu trn csblend PE/CSTN, Tp ch Khoa hc v Cng ngh,V.35, No1, 18-23 (1997).

44. Trn Thanh Sn, Nguyn Quang, Thi Hong, Bo co tng ktti cp Trung tm Khoa hc Tnhin v Cng nghQuc giagiai on 2000-2001 Trin khai cng nghchto cc sn phmk thut trn c s vt liu polyme blend ng dng vo ngnhGTVT ng st v ngnh dt may thay thhng nhp khu, H

Ni (2002).

45. Nguyn Quang, Quang Khng, Nguyn Vn Khi, Phm AnhDng, L Th M Hnh, Nghin cu nh hng ca cng nghtrn hp n tnh cht ca vt liu CSTN thp vi LDPE ngdng lm m chng va p tu bin, Tp ch Ha hc,T.39, No4B, 46-52 (2001).

46. Thi Hong, Bo co tng kt ti KH-CN cp Vin Khoa hcv Cng ngh Vit Nam Nghin cu ch to vt liu polyme

blend trn c s polyolefin vi polyamit v cao su c s dng


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Thi Hong44

cht tng hp polyme mi thch hp ng dng cho ngnhGTVT ng st, ngnh hng khng v ngnh du kh, H Ni,thng 4, 40 (2004).


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Chng II

CC PHNG PHP XC NH STNG HPCA CC POLYME

Da vo s phn chia cc dng polyme blend trnh by I.4(polyme blend ho trn v tng hp hon ton, polyme blend ho

trn v tng hp mt phn, polyme blend khng ho trn v khngtng hp), cc chuyn gia tng kt cc phng php xc nhstng hp ca cc polyme. l cc phng php da vo ginpha, nht dung dch polyme blend, m men xon ca polymeblend trng thi nng chy, tnh cht chc, phhng ngoi, nhhin vi in t v kt hp cc phng php nh gi kh nngtng hp ca cc polyme.

II.1. Phng php gin pha

Nh trnh by I.2, sho trn v stng hp ca cc polymelin quan cht chti nhit ng hc qu trnh trn hp v ho tanchng cc iu kin khc nhau v phthuc vo nhiu yu tnhkhi lng phn t, cu to, cu trc, phn cc, nhit ho tanca polyme... Da vo gin pha ca cc polyme trong mt h(phn nh sphthuc ca nhit trn ln, nhit ho tan v thngstng tc Flory-Huggins vo thnh phn ca cc polyme), ngita c thnh gi s to thnh mt pha hay tch cc pha polyme.Hn hp polyme vi hiu ng nhit trn ln m (tonhit) c nhit

ho tan ti hn di (LCST). Nm pha trn ng LCST, 2polyme khng trn ln (tch pha) v nm pha di ng LCST,2 polyme ho trn tt vi nhau. Ngha l, khi lm lnh, cc polymeho tan vo nhau tt hn. Hn hp polyme vi hiu ng nhit trnln dng c nhit ho tan ti hn trn (UCST). Nm phadi ng UCST, 2 polyme khng trn ln nhau v khi tng nhit, vng pha trn ng UCST, 2 polyme ho trn tt vo nhau.


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Thi Hong46

Cc polyme ho tan vo nhau khi tng nhit trn ln [1 - 4]. Trnthc t c cc dng gin pha ca hn hp polyme nh: ch cnhit ho tan ti hn di (TLCST); chc nhit ho tan ti hntrn (TUCST); va c nhit ho tan ti hn di, va c nhit ho tan ti hn trn vi TUCST < TLCST; gin pha vng kn viTUCST< TLCST(ngoi vng, 2 polyme ho trn cn trong vngxy ra tch pha 2 polyme) v khng c nhit ho tan ti hn(hnh I.3) [2, 3, 5].

xy dng gin pha, ngi ta thng da vo php o c/ m. Nh xc nh im c hay im m ca hn hppolyme (im ranh gii gia ho tan v khng ho tan/tch pha cacc polyme) c thvc ng cong im mtheo thnh phnhn hp polyme. im mchnh l nhit cng tn xnh sng thay i bt thnh lnh/bt ng. Mun xc nh imm, trc ht cn phi to mng polyme blend bng cch ho tancc polyme trong cng mt dung mi hoc trn hp c hc, trnhp nng chy cc polyme vi cc thnh phn khc nhau. Cc mngny c gia nhit hoc lm ngui qua im m. im m camng polyme blend c thc xc nh trc tip trn knh hin vibng mt thng hoc nhdetector quang in. Gn y, phngphp tn xnh sng c sdng rt phbin xc nh immca mng polyme blend. Sm/c chnh l kt quca tn x

nh sng do skhng ng nht/tch pha ca polyme blend [2].H. Y. Chen, S. P. Chum v cc cng s nghin cu cc gin

pha - cc ng cong im m (Tcl) ca cc copolyme etylen-styren vi hm lng styren khc nhau (57,1 - 67,7%). Cc tc ginhn thy, cc polyme blend u c nhit ho tan ti hn trn.Tuy nhin, khi gim khi lng phn tv gim skhc nhau vhm lng styren trong cc copolyme etylen-styren, nhit hotan ti hn trn ca polyme blend gim. iu ny cho php nhnnh hn hp cc copolyme etylen-styren ni trn chuyn tkhng

tng hp sang tng hp mt phn [6].Nhit ho tan ti hn trn c quan st thy trn gin

pha ca polystyren (PS) vi polybuten, polyizopren, polybutadien,poly--caprolacton, polymetylphenylsiloxan v poly(butadien-co-metylstyren). Nhvy, polyme blend ca PS vi cc polyme cn lil polyme blend khng tng hp [1].


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Chng II. CC PHNG PHP XCNH STNG HP CA CC POLYME 47

Trn gin pha ca cc polyme blend to thnh tcopolymestyren-co-4-vinylphenol (STVPh) vi hm lng 4-vinylphenolkhc nhau (7 v 9%) v poly(n-hexyl metacrylat) (PHMA), tt c

cc polyme blend u xut hin nhit ho tan ti hn di (hnhII. 1). R rng l cc polyme blend ny ho trn tt vi nhau [2].

Tcl(oC)

[STVPh(x)] (%)

Hnh II.1. Gin pha ca hn hp copolyme styren-co-4-vinylphenol (STVPh) vi hm lng 4-vinylphenol khc nhau

(x=7 v 9%) v poly(n-hexyl metacrylat) (PHMA) [2].

Khi nghin cu gin pha ca hn hp copolyme etylen-propylen-dien (EPDM)/polystyren-co-acrylonitril (SAN) c hmlng acrylonitril 30%, cc tc ginhn thy 2 polyme ny khng

tng hp vi nhau mi tlv trn gin pha ca chng xuthin nhit ho tan ti hn trn (hnh II. 2) [7]. Tin hnh trnghp ghp monome c cc nh metyl metacrylat vo EPDM,copolyme ny tr thnh c cc. Trn gin pha ca EPDM-g-PMMA (phn trm ghp MMA vo EPDM 26%) v SAN xut hinnhit ho tan ti hn di (hnh II. 3). iu cho php khngnh EPDM-g-MMA v SAN ho trn vi nhau tt ccc tl


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Thi Hong48

kho st. iu ny c th gii thch bi cc i phn t PMMAtrong EPDM-g-PMMA ng vai tr tng cng tng hp EPDMv SAN. Nhm C=O trong EPDM-g-PMMA tng tc mnh vinhm CN trong SAN (tng tc lng cc) [7].

[ S A N ] ( % )

1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0

Tcl

(oC)

1 2 0

1 4 0

1 6 0

1 8 0

2 0 0

2 2 0

Hnh II.2. Gin pha ca polyme blend EPDM/SAN [7].

[ S A N ] (% )

1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0

Tcl

(oC)

4 0

6 0

8 0

1 0 0

1 2 0

1 4 0

1 6 0

1 8 0

Hnh II.3. Gin pha ca polyme blend EPDM-g-PMMA/SAN [7].

M. Taimoori v cng s xy dng gin pha ca hn hppolystyren (PS) vi polyvinyl clorua (PVC) v PS vi polyvinylaxetat (PVAc). Trn gin pha ca cc hn hp polyme u cnhit ho tan ti hn di v nhit ho tan ti hn trn khi s


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dng PVC v PVAc c khi lng phn t thp [3]. Khi trnpolymetyl metacrylat (PMMA) v polycacbonat (PC), F. Case thu c gin pha ca hn hp polyme dng vng kn vi cc

im mt454 ti 514o

C [8] (minh hotrn hnh II. 4). Nhvy,cc hn hp polyme ni trn chc khnng ho trn v tng hpmt phn vi nhau.

T

UCST

LCST

0 100

[PC] (%)

Hnh II.4. Gin pha minh hopolyme blend PMMA/PC.

Cc cp polyme c cc sau y c nhit ho tan ti hndi: PVC v polymetacrylat, polyvinylidenflorua v polyacrylathoc polymetacrylat, poly--caprolacton v SAN. Chng to thnhmt hng th (ho trn hon ton) v ch b tch pha khi tngnhit [1].

T gin pha ca hn hp poly(etylen oxit) (PEO) vpoly(ete sunphon) (PES), G. Dreezen, D. A. Ivanov v cng scho

thy hn hp polyme c nhit ho tan ti hn di thp nht tlPEO/PES 90/10 v 2 polyme ho trn vi tt ccc tlnhitdi 75oC. Nhit mca polyme blend PEO/PES cc tl75/25 v 50/20 ln lt l 80 v 101oC [9]. Kt hp vi nghin cunh hin vi in tqut ca cc polyme blend PEO/PES, cc tc gikhng nh polyme ny ho trn kch thc nanomet.

2 pha

1 pha


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Thi Hong50

Trn gin pha ca hn hp polyme xellulo axetat butyrat(CAB)/poly(etylen glycol) (PEG) c nhit ho tan ti hn dikhi khi lng phn t ca PEG ln hn 8.000. Polyme blendCAB/PEG c nhit ho tan ti hn di 168oC vi t lCAB/PEG 40/60. iu chng tCAB v PEG ho trn tt. Do, mng polyme blend thu c trong sut [10].

Nhvy, xy dng gin pha ca polyme blend theo t lcc polyme thnh phn l mt cng crt c hiu qunh gikhnng ho trn v tng hp ca cc polyme. Nhgin phata c thbit c 2 polyme ho trn tt (tng hp hon ton),ho trn v tng hp mt phn hay khng ho trn v khngtng hp.

II.2. Phng php da vo nhit thutinh ho

Theo cc chuyn gia trong lnh vc ho l polyme, trng thimm cao ca polyme, cc mt xch trong i phn t c linhng ln nn ddng thay i hnh dng sp xp. Trong phm vinhit no y, polyme bcng li m khng to thnh mng litinh thgi l thutinh ho polyme. Qu trnh thutinh ho polymel qu trnh chuyn ttrng thi mm cao sang trng thi thutinh,qu trnh ny km theo sthay i cc tnh cht vt l ca polyme

nh thtch, t trng, cc tnh cht chc, cc tnh cht in mi[4]. Nhit thu tinh ho (Tg - glass transition temperature) capolyme chnh l nhit polyme chuyn tcng v gin sangmm v dun v ngc li. N phn nh s linh ng, mmca cc mch i phn tpolyme. xc nh nhit thu tinhho ca polyme ngi ta thng da vo cc phng php ng tincy nh xc nh th tch ring (phng php dilatomet), o tnhit, o m un n hi, nhit lng vi sai qut (DSC), phn tchc nhit (TMA), phn tch c nhit ng (DMTA), xc nh tnhcht in nhtang ca gc tn hao in mi... [1, 2, 4, 11].

Xc nh nhit thu tinh ho ca polyme blend rn l mtcng cquan trng nh gi mc ho trn v tng hp cacc polyme. Nu polyme blend c 2 nhit thutinh ho Tgca 2polyme thnh phn hay polyme ban u (parent polymers), 2polyme khng tng hp v c hin tng tch 2 pha polyme. Nupolyme blend c 2 nhit thutinh ho Tgv 2 gi trTgchuyn


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dch tTgca polyme ny vpha Tgca polyme kia th 2 polymetng hp khng hon ton (tng hp mt phn). Nu polymeblendchc mt nhit thutinh ho duy nht nm gia 2 Tg

ca 2 polyme thnh phn, 2 polyme ho trn v tng hp honton [11, 12]. Trong trng hp ny, hn hp polyme dng ngth, mt pha. S ng nht ca cc polyme trong hn hp cquan st mc nano hoc mc phn t. Kch thc ht(particle size) trong polyme blend t2 n 15 nm [2, 12]. Di yxem xt stng hp ca mt spolyme blend nhxc nh nhitthutinh ho ca n.

B. M. P. Ferreira, C. A. Zavaglia v cng s chto polymeblend trn c s poly(L-lactic axit) (PLLA) v

poly(hydroxybutyrat-co-hydroxyvalerat) (PHBV) bng phngphp c phun. S dng phng php nhit lng vi sai qut vphng php phn tch cnhit ng (da vo ng cong m untn hao (E) - nhit v tan - nhit ), cc tc gi xc nhnhit thutinh ho ca PLLA v PHBV trong polyme blend. Ccgi tr nhit thu tinh ho ca PLLA v PHBV trong polymeblend cc t lkhc nhau theo cc ng cong m un tn hao(E) - nhit dao ng quanh 96 v 42oC. Da vo cc ngcong tan - nhit , Tg ca PLLA v PHBV ln lt dao ng

quanh 101 v 47

o

C. Vi phng php nhit lng vi sai qut, cctc gicng thu c 2 gi trnhit thutinh ho tng ng viTgca 2 polyme ban u. iu ny cho php khng nh PLLA vPHBV khng tng hp vi nhau [13].

X. B. Xie, K. C. Tam v cng s ch to polyme blend tpolyme tinh th lng (LCP) co-polyeste v copolyme styren-acrylonitril-butadien (ABS) bng phng php n trn my n 2trc vt xon 280oC. Cc tc gi nghin cu nhit thutinhho ca pha nn ABS (tc l Tg ca polystyren-co-acrylonitril,

SAN) khi hm lng LCP thay i bng cc phng php DSC vDMTA. Nhit thutinh ho ca SAN trong polyme blend khngph thuc vo hm lng LCP, hu nh khng thay i khi hmlng LCP thay i (bng II.1) [14]. iu ny chng tcc polymeLCP v ABS khng tng hp.


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Bng II.1. Tgca ABS (SAN) vi cc hm lng LCP khc nhau [14].

Hm lng LCP (%)Tg(oC)

0 10 20 30 50 100DMTA 115,1 116,2 115,8 113,8 115,4 84,5

DSC 104,5 103,4 104,3 104,5 103,5 -

Khi nghin cu s bin i nhit thu tinh ho capolyamit 12 (nylon 12) v copolyme ABS trong hn hp 2polyme, B. M. Rao, P. R. Rao v cng snhn thy c schuyndch Tg ca polyme ny v pha Tg ca polyme kia. S chuyn

dch Tgln nht l 61,5 v 75,8

o

C tlnylon 12/ABS l 60/40.Nh vy 2 polyme nylon 12 v ABS tng hp mt phn vinhau. S tng tc gia 2 polyme trn xy ra mnh nht t l60/40 (bng II.2 v hnh II.5) [15].

Bng II.2. Tgca nylon 12 v ABS cc tlkhc nhau [15].

Tlnylon 12/ABS(%)

Tgca nylon 12(oC)

Tgca ABS(oC)

100/0 48,0 -

90/10 50,0 90,5

80/20 56,0 81,7

70/30 59,2 77,9

60/40 61,5 75,8

50/50 55,4 79,3

40/60 51,5 89,9

0/100 - 99,2


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Nhit (oC)

Hnh II.5. Gin DSC ca nylon 12, ABS v blendcc tlkhc nhau [15].

J. Sheng, H. Ma v cng s nghin cu nhit thu tinhho ca polyamit 6 (nylon 6) v polyetylen t trng thp (LDPE)trong polyme blend c v khng c LDPE ghp axit acrylic (LDPE-g-AA). Nhit thutinh ho ca nylon 6 v LDPE khng thay ikhi t l nylon 6/LDPE thay i (tng ng l 97,7 v 88,6oC).iu chng tnylon 6 v LDPE l 2 polyme khng tng hp[16]. Nhit thu tinh ho ca cc polyme thnh phn trongpolyme blend nylon 6/LDPE-g-AA v nylon 6/LDPE-g-AA/LDPEc schuyn dch theo t lca cc polyme thnh phn. Nhvyc thkhng nh cc polyme blend nylon 6/LDPE-g-AA v nylon6/LDPE-g-AA/LDPE bn tng hp (semi-compatible) haytng hp mt phn. iu ny c thgii thch bi phn ng gia

nhm cacboxyl trong LDPE-g-AA vi nhm amin cui mch xy ra bmt ranh gii pha khi trn hp nng chy nylon 6 vLDPE-g-AA cng nhnylon 6, LDPE-g-AA v LDPE.

Phn ln polyme blend t polyimit vi cc copolyme arylat-cacbonat c 2 nhit thutinh ho, do cc polyme blend nykhng tng hp. Trong khi , mt spolyme blend tpolyamit


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hoc polyimit vi polyarylat chc mt nhit thutinh ho, tcl cc polyme blend ho trn tt [17].

Mng polyme blend ca si fibroil (nhnylon 2) vi nylon 66

c mt nhit thu tinh ho thp hn Tg ca nylon 66 (khong50oC) khi hm lng si fibroil khng vt qu 50%. Khi hmlng si fibroil ln hn 50%, polyme blend si fibroil/nylon 66khng c nhit thu tinh ho. Nhvy, si fibroil v nylon 66chho trn v tng hp tt khi hm lng si fibroil khng vtqu 50% [18].

Ph thuc vo t lca poly-axit lactic (PLA) v bt la m -gluten, trong polyme blend PLA/gluten c thc mt hoc 2 nhit thu tinh ho ( cc t l PLA/gluten 20/80, 50/50 v 80/20,

polyme blend c mt Tg; cc t l khc ca 2 polyme, polymeblend c 2Tg). Do , PLA v gluten ch tng hp mt phn vinhau [19].

H. Y. Chen, Y. W. Cheung v cc cng s xc nh nhit thu tinh ho ca cc polyme blend trn c s copolyme etylen-styren c hm lng styren khc nhau (4,3 - 70,9%). Hu ht ccpolyme blend ni trn c 2Tgv Tgca cc copolyme etylen-styrenc xu hng tin vpha Tgca nhau trpolyme blend to thnh tcc copolyme etylen-styren c hm lng styren gn nhau (52 v

58%). Nh vy, cc copolyme etylen-styren ch tng hp mtphn vi nhau [20].

Mng polyme blend -chitin/poly(vinyl alcol) chc mt nhit thu tinh ho tt c cc t l. Tg ca polyme blend tng nhtheo hm lng -chitin. Hu ht cc mng polyme blend -chitin/poly(vinyl alcol) u trong sut. Do , 2 polyme -chitin vpoly(vinyl alcol) ho trn tt vi nhau [21].

Phng H, E. Schacht nghin cu cc polyme ng xuynthm (interpenetrating polymer network-IPN) trn cspolyuretan(PU) li ho vi polydimetylaminetylmetacrylat (PDMAEMA)hoc polymetacrylic axit (PMA) [22, 23]. y l mt dng polymeblend c bit. Kt quxc nh nhit thutinh ho ca hn hpPU/PDMAEMA cho thy, Tg ca 2 polyme c xu hng xch lign nhau khi tng hm lng PDMAEMA. iu ny c th giithch bi lin kt hydro gia nhm NH - uretan trong PU v ccnhm nhn proton trong PDMAEMA nh uretan cacbonyl, ete


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cacbonyl, amin bc ba. R rng 2 polyme c san xen khng honton, ngha l chho trn v tng hp mt phn do khng phi ttc cc lin kt hydro u c to thnh trong IPN (do mt phn

nhm C=O trong 2 polyme khng tham gia lin kt). Ngc li, hnhp cc polyme PU v PMA chc mt nhit thutinh ho duynht. iu ny cho php khng nh PU v PMA tng tc honton v 2 polyme ho trn tt vi nhau.

C mt sphng trnh tnh ton v dbo nhit thutinhho ca polyme blend ho trn v tng hp hon ton (c mt gitrTg) theo l thuyt v kinh nghim. Chng c xy dng trn csquan hphthuc gia nhit thutinh ho ca polyme blendvo cc tlcc polyme thnh phn, Tgca cc polyme ban u v

bn cht tng tc gia cc polyme thnh phn.Trng hp l tng l nhit thutinh ho ca polyme

blend tun theo phng trnh cng tuyn tnh.

Tg= W1Tg1+ W2Tg2 (II.1)

Trong :

W1, W2: phn khi lng hoc phn th tch ca polyme 1 v

polyme 2.Tg1, Tg2: nhit thutinh ho ca polyme 1 v polyme 2 ban

u.

Nu polyme 2 c Tgln hn polyme 1, khi Tgca polymeblend tng tuyn tnh theo tlca polyme 2 trong h(hnh II.6).Tuy nhin, c mt spolyme blend c Tg ln hn nh don(ng Tgnm pha trn ca ng thng) do cc i phn tca cc polyme tng tc vi nhau rt mnh. a s cc trnghp, do cc i phn t ca cc polyme tng tc vi nhau yu

nn Tgca polyme blend thng nhhn nhdon (ng Tgnm pha di ca ng thng). Trong 2 trng hp ny, sphthuc gia nhit thutinh ho ca polyme blend vo tlcc polyme thnh phn, Tg ca cc polyme ban u v bn chttng tc gia cc polyme c m tbng cc phng trnh dbo theo kinh nghim nh phng trnh Fox, phng trnh


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Thi Hong56

Gordon-Taylor, phng trnh Kwei, phng trnh Couchman,phng trnh Braun-Kovacs... [2, 24].

Hnh II.6. Sphthuc Tgca polyme blend ho trn vo tlccpolyme thnh phn.

Khi nghin cu sph thuc gia nhit thu tinh ho capolyme blend PMMA/PC c cu trc nano (vi Tg ln lt l 112v 144oC), R. Y. F. Liu, Y. Jin v cc cng s nhn thy polymeblend PMMA/PC chc mt nhit thutinh ho tt ccc tl2 polyme thnh phn, v vy, 2 polyme ho trn tt vo nhau. Tgca PMMA tng khong 10oC trong khi Tg ca PC gim khong22oC. Tg ca polyme blend ho trn ni trn kh ph hp viphng trnh cng tuyn tnh hoc phng trnh Fox di y.

1/Tg= W1/Tg1+ W2/Tg2 (II.2)

Nhit thutinh ho ca polyme blend PMMA/PC (tl1/1,phn th tch) xc nh bng phng php DSC l 122oC. N khgn vi Tg ca polyme blend tnh ton theo phng trnh cngtuyn tnh l 128oC v theo phng trnh Fox l 126oC [25].

Tgca polyme 2

Tgca polyme

Tg

% Polyme 2


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Trong cc cng trnh [26, 27], cc tc gi xc nh nhit thu tinh ho ca polyme blend poly(etylen terephtalat)(PET)/poly(etylen 2,6-naphtalat) (PEN) c ch to bng phng

php trn nng chy. Khi 2 polyme PET v PEN c nht thctng tnhau (intrinsic viscosity, 0,63 v 0,65dl/g), Polyme blendchc mt nhit thutinh ho tt ccc tlPET/PEN, do ,PET v PEN ho trn hon ton [26]. Nhit thu tinh ho capolyme blend xc nh bng DSC cc t lPET/PEN hon tonph hp vi Tgca polyme blend tnh ton theo phng trnh Fox.

Polyme blend ca copolyme styren-butadien-styren (SBS) vpoly(2,6-dimetyl 1,4-phenylen oxit) (PPO) chc mt nhit thutinh ho nm gia Tgca 2 polyme thnh phn. iu chng t

PPO ho trn hon ton vi cc khi PS trong SBS [28]. Do thngstan (solubility parameter) ca PPO v PS rt gn nhau, ln lt l9,6 v 9,5 (cal/cm3)0,5 nn pha cng (PS) trong SBS d ho tantrong PPO. Trong polyme blend ny, Tgca pha mm khng thayi trong sut qu trnh trn nng chy 2 polyme 180oC. Nhvy,PPO chtng tc mnh vi pha cng PS trong SBS. Cc tc ginhn thy phng trnh Fox khng ph hp d on Tg capolyme blend SBS/PPO theo tl2 polyme thnh phn. Trong khi, phng trnh Gordon-Taylor di y rt ph hp don

Tgca polyme blend ny

cc t

lkhc nhau:

(II.3)

Trong :

W1, W2: phn khi lng hoc phn th tch ca polyme 1 vpolyme 2

Tg1, Tg2: nhit thutinh ho ca polyme 1 v polyme 2

k: hng s phn nh ln tng tc gia 2 polyme trongblend

Gi trk cng cao, tng tc gia 2 polyme cng mnh. Thngsk bng 2/1v l schnh lch hsdn nnhit giatrng thi lng v trng thi thutinh nhit thutinh ho ca

21

2211

kWW

TkWTWT

gg

g+

+=


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Thi Hong58

tng polyme. Ni chung k thng c sdng nhmt thng sgn ng [30, 29].

Trn hnh II.7 l th Gordon-Taylor ca polyme blend

SBS/PPO theo t l ca 2 polyme. Tg ca polyme blend xc nhbng thc nghim rt ph hp vi Tgca polyme blend dbo theophng trnh Gordon-Taylor [28].

Hnh II.7. thGordon-Taylor ca polyme blend ho trn

SBS/PPO [28].

J. W. Park v S. S. Im xc nh polyme blend poly(L-lacticaxit) (PLLA)/poly(vinyl axetat-co-vinyl alcol) (PVA) l polymeblend ho trn do chc mt nhit thutinh ho tt ccc tlca 2 polyme thnh phn. So snh vi Tg ca polyme blendPLLA/PVA xc nh bng thc nghim, cc tc gi nhn thy nph hp vi Tgca polyme blend c tnh ton theo phng trnhGordon-Taylor v thng stng tc k = 2,8 [29].

K. Krutphun v P. Supaphol nghin cu polyme blend capoly(trimetylen terephtalat) (PTT) v PEN trng thi v nhhnh. Polyme blend ny chc mt nhit thu tinh ho tt ccc tlPTT/PEN. Nhvy, 2 polyme PTT v PEN ho trn honton [30]. S ph thuc Tg vo thnh phn ca polyme blendPTT/PEN ph hp vi phng trnh dbo Gordon-Taylor (hstng tc k = 0,57).


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Ngoi cc polyme blend ho trn c mt nhit thutinh hovi cc polyme tng tc mnh hoc tng tc yu vi nhau cn ccc polyme blend ho trn m cc polyme thnh phn khng c

tng tc c bit. Tuy nhin, Tgca chng theo tl2 thnh phnthng lch m so vi tnh ton l thuyt. Chng hn, polyme blendca PMMA izotactic v PMMA syndiotactic. Nhit thutinh hoca polyme blend ny ph hp vi Tgca polyme blend dbo theophng trnh Gordon-Taylor [2].

C. F. Huang, S. W. Kuo v cc cng s xc nh nhit thutinh ho ca polyme blend trn csPMMA v PMMA chacc oligome silsesquioxan a din (PMMA-POSS) tng hp bngkthut trng hp gc chuyn nguyn tvi nha phenolic. Tt c

cc polyme blend PMMA/nha phenolic v PMMA-POSS/nhaphenolic u c mt nhit thu tinh ho tt c cc t l 2polyme thnh phn. iu chng t cc polyme blend ni trnho trn hon ton. Cc tc gi xy dng thphthuc gianhit thu tinh ho ca cc polyme blend vi t l 2 polymethnh phn v Tgca cc polyme ban u bng phng trnh cngtuyn tnh, phng trnh Fox, phng trnh Kwei (hnh 10) [31].Phng trnh Kwei l phng trnh d bo v tnh ton Tg capolyme blend trn cspht trin phng trnh Gordon-Taylor:

(II.4) (II.4)

Trong :

q l thng sgn ng. N tng ng vi ln cc tng tcc bit trong polyme blend v phn nh cn bng gia tng tc t

lin kt (self-association) trong polyme v tng tc c bit giacc polyme.

Phng trnh Kwei phn nh chnh xc sphthuc Tgcapolyme blend vo thnh phn 2 polyme trong cc polyme blend nitrn. Thnh 10, cc tc gi tnh c k = 1, q = -37 cho polymeblend PMMA/nha phenolic v k = 1, q = 35 cho polyme blendPMMA-POSS/nha phenolic (sdng phng php tnh ton gi tr

2121

2211WqW

kWW

gTkW

gTW

gT +

+

+=


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Thi Hong60

bnh phng ti thiu). Gi tr q = -37 cho polyme blendPMMA/nha phenolic cho thy tng tc tlin kt trong nhaphenolic ln hn cc tng tc c bit gia PMMA v nhaphenolic.

Tlthnh phn 2 polyme

Hnh II.8. Sphthuc Tgca polyme blend vo thnh phn2 polyme [31].

a - Phng trnh Fox, b - Phng trnh cng tuyn tnh,

c - Phng trnh Kwei cho polyme blend PMMA-POSS/nhaphenolic, d - Phng trnh Kwei cho polyme blend

PMMA/nha phenolic

Cc vng trn en l s liu thc nghim ca polyme blendPMMA-POSS/nha phenolic; Cc hnh vung en l s liu thcnghim ca polyme blend PMMA/nha phenolic.

Bng II.3 lit k mt sphng trnh phbin dbo nhitthutinh ho ca polyme blend ho trn vo tlv Tgca ccpolyme thnh phn [1, 2].


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Bng II.3. Sphthuc nhit thutinh ho ca polymeblend ho trn vo tlv nhit thutinh ho ca cc

polyme thnh phn [1, 2].

Tn phngtrnh

Cng thc

Cng tuyn tnh Tg= W1Tg1+ W2Tg2

Fox 1/Tg= W1/Tg1+ W2/Tg2

Gordon-Taylor

Kwei

Couchman

Braun-Kovacs

Trong , Tgi, Wi, i: nhit thutinh ho, phn khi lng,phn thtch ca polyme i; : schnh lch hng sdn nnhitgia trng thi thu tinh v trng thi lng; fgphn th tch t doca mt polyme nhit thutinh ho ca n.

2121

2211

WqW

kWW

TkWTWT

ggg +

+

+=

21

2211

kWW

TkWTWT

gg

g+

+=

21

2211

lnlnln

kWW

TkWTWT

ggg

+

+=

11

2122

1

++=

gfTT

g

gg


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Thi Hong62

II.3. Phng php da vo nht dung dch polyme blend

o nht ca dung dch polyme blend l mt trong nhng phngphp quan trng nh gi stng tc ca cc polyme trong mt

dung mi no . T c thdon khnng tng hp ca ccpolyme. Csl thuyt ca vn ny nhsau: tng tc y giacc polyme ho tan trong mt dung mi chung c thgy ra scongt cc b, cc cun ca cc i phn t polyme v do lmgim nht ca dung dch polyme blend so vi nht ca dungdch polyme blend c tnh ton trn cscng tuyn tnh theo nht v tlca cc polyme thnh phn. Trong trng hp ny, 2polyme khng c khnng tng hp. Ngc li, khi cc i phntca 2 polyme c tng tc ho hc v vt l (ht nhau mnh nh

lin kt hydro chng hn), kch thc phn tca chng cng nhnht ca dung dch polyme blend stng ln so vi tnh ton lthuyt. Do , 2 polyme c khnng tng hp mt phn vi nhau(hnh II.9). xc nh nht ca dung dch polyme ngi tathng s dng cc nht k mao qun (capillar) nh nht kOtswal, nht kUbbelohde, nht kCannon-Fanske [11].

Pp

[]hh

[]tt

[]hh

Nng ca hn hp polyme (phn thtch)

Hnh II.9. Sphthuc nht ca dung dch polyme blend vonng thtch ca cc polyme.

2 polyme A vB tng hp mt phn

2 polyme A vB khng tng hp


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[]tt= []AA+ []BB (II.5)

Trong :

[]tt: nht ca dung dch polyme blend A/B

[]A, []B: nht ca dung dch polyme A v polyme B trongcng mt dung mi

A, B: nng ca polyme A v polyme A (phn thtch)

Khi nghin cu nht thc ca dung dch polyme blendetylen-propylen-dien monome (EPDM)/cao su thin nhin cc tlkhc nhau c v khng c 10% EPDM-anhydrit maleic (EPDM-

MA) trong dung mi toluen, S. H. Botros nhn thy vi dung dchpolyme blend EPDM/cao su thin nhin (CSTN) khng c EPDM-MA, ng nht thc - tlthnh phn l mt ng cong vlun nm di ng nht thc - tlthnh phn ca dung dchpolyme blend EPDM/CSTN c EPDM-MA (l mt ng thng).iu ny cho thy polyme blend EPDM/CSTN l polyme blendkhng tng hp. EPDM-MA c tc dng lm cho EPDM vCSTN tng hp mt phn vi nhau [32].

Chu Chin Hu nh gi kh nng ho trn v tng hp

ca cc polyme blend PVC/CSTN epoxy ho v cao suclopren/CSTN epoxy ho bng phng php o nht trong ccdung mi tng ng l xyclohexanon v toluen [33]. Tc ginhnthy khi hm lng nhm epoxy trong CSTN epoxy ho nh hn50%, nht ring ca dung dch polyme blend PVC/CSTN epoxyho u nhhn nht ring ca tng cu tv thp hn ngchun (ni nht ring ca dung dch PVC v dung dch CSTNepoxy ho). Nh vy, khi hm lng nhm epoxy trong CSTNepoxy ho nhhn 50%, PVC v CSTN epoxy ho hu nhkhngtng hp. C thgii thch iu ny nhsau: khi hm lng nhm

epoxy trong CSTN epoxy ho nh hn 50%, lc tng tc gianhm epoxy trong CSTN epoxy ho vi nguyn t clo ca nhaPVC cha ln thng c tng tc y gia PVC v CSTNepoxy ho do chng c phn cc rt khc nhau [33].

Khi hm lng nhm epoxy trong CSTN epoxy ho ln hn50%, nht ring ca dung dch PVC/CSTN epoxy ho u lnhn nht ring ca tng cu tv cao hn ng chun (ni


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Thi Hong64

nht ring ca dung dch PVC v dung dch CSTN epoxy). C thgii thch hin tng ny nhsau: khi hm lng nhm epoxy trongCSTN epoxy ho ln hn 50%, do nh hng ng thi ca 2 yut: mt nhm chc phn cc tng, kh nng va chm gia ccnhm chc hot ho ca CSTN epoxy ho vi nha PVC tng lnrt cao cc tlpolyme thnh phn. Tng tc gia nhm epoxytrong CSTN epoxy ho vi nguyn tclo hot ng ca nha PVCln thng tng tc y gia 2 polyme v lm cho mch iphn tca PVC v CSTN epoxy ho an xen vo nhau. Do , nht ring ca dung dch polyme blend PVC/CSTN epoxy ho caohn nht ring ca dung dch tng cu t. Kt quo nhtchng tkhi hm lng nhm epoxy trong CSTN epoxy ho nhhn 50%, PVC v CSTN epoxy ho khng tng hp hoc tng

hp mc thp. Khi hm lng nhm epoxy trong CSTN epoxyho ln hn 50%, PVC v CSTN epoxy ho c khnng tng hpmnh hn.

Vi dung dch polyme blend cao su clopren/CSTN epoxy ho,khi hm lng nhm epoxy trong CSTN epoxy ho nhhn 25%v tlcao su clopren nhhn 50%, nht ring ca dung dchpolyme blend cao su clopren/CSTN epoxy ho u nm di ngchun (ni nht ring ca dung dch cao su clopren v dung dchCSTN epoxy ho). iu ny c thgii thch bi sthp ca cc

i phn tCSTN epoxy ho ln hn tng tc gia cc i phn tCSTN epoxy ho v cao su clopren cng nh tng tc y giacc i phn tca 2 loi cao su do khc nhau vmc phn cc.Tng tc y s cng mnh khi hm lng nhm epoxy trongCSTN epoxy ho cng thp v do , CSTN epoxy ho v cao suclopren khng tng hp vi nhau.

Khi hm lng nhm epoxy trong CSTN epoxy ho ln hn25%, nht ring ca dung dch polyme blend cao suclopren/CSTN epoxy ho u nm trn ng chun mi t l.

Trong trng hp ny, mc phn cc ca CSTN tng ln ngk v tng tc gia cc nguyn t clo trong cao su clopren vinhm epoxy trong CSTN epoxy ho thng c tng tc ygia 2 loi cao su. Cng tng mc epoxy ho ca CSTN th nht ring ca dung dch polyme blend cao su clopren/CSTN epoxyho cng ln v xu hng lch ra khi ng chun vpha dng


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cng ln, ngha l khnng tng hp ca cao su clopren v CSTNepoxy ho cng tng.

Theo Huggins, quan hgia nht ring []rv nng cadung dch polyme c biu din nhsau:

[]r/C = [] + K[]2C (II.5)

vi K l h sHuggins ca polyme trong dung mi bit; nht thc ca dung dch polyme [34].

nht ring ca dung dch polyme blend c thhin biphng trnh sau [35, 36]:

[]r(hh) = [1].C1+ [2].C2+ b11C12+ b22C2

2+ 2(b11b22)1/2C1C2

(II.6)

Trong :

[]r(hh) l nht ring (specific viscosity) ca dung dchpolyme blend; 1, 2 l nht thc (intrinsic viscosity) ca dungdch polyme 1 v polyme 2 trong cng mt dung mi v cng mtiu kin o; C1 v C2 l nng ca polyme 1 v polyme 2 trong

dung dch polyme blend; b11v b22l hstng tc tng ng vicc i phn t polyme 1 v polyme 2 trong dung mi bit;b12= (b11.b22)

1/2 l hstng tc gia cc polyme trong hn hp.

Tphng trnh ny ngi ta pht trin thnh phng trnhtnh ton nht ring ca dung dch polyme blend theo kinhnghim nhsau:

[]r(hh) = [C1(r(1))c+ C2(r(2))c]/C (II.7)

Trong :

[]r(hh) l nht ring ca dung dch polyme blend; (r(1))cv(r(2))cl nht ring ca dung dch polyme 1 v polyme 2 nngC = C1 + C2v C1 v C2 l nng ca polyme 1 v polyme 2trong dung dch polyme blend.


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Thi Hong66

Mc d quan htrn khng hon ton ng nhl thuyt songphng trnh ny vn c sdng tnh ton nht ring cadung dch polyme blend.

Hs tng tc gia cc polyme b12phng trnh tnh tonnht ring theo l thuyt khng c ngha khi cc hsb11v b22mang gi tr m. V th, ngi ta s dng biu thc b12 = (b11 +b22)/2 thay thcho biu thc b12= (b11 .b22)

1/2 [35, 36]. Khi nht ring ca dung dch polyme blend c vit nhsau:

[]r(hh) = [1].C1+ [2].C2+ b11C12+ b22C2

2+ ((b11+ b22)/2)C1C2(II.8)

Thng sb12 = (b11+ b22)/2 c trng cho tng tc gia ccpolyme trong hn hp. C thbit gia polyme 1 v polyme 2 chay khng c tng tc khi so snh cc gi tr b12 xc nh bngthc nghim v b*12 tnh ton theo l thuyt.

Kh nng tng hp ca hn hp polyme c d bo bithng s:

b = b12 - b*12 (II.9)

Gi tr b m cho bit dung dch polyme blend khng tnghp v tng tc y gia cc polyme. Ngc li, gi trb dngcho bit dung dch polyme blend c khnng tng hp mt phndo tng tc ht gia cc polyme.

V. Suthar, A. Pratap v cng s nghin cu nht cadung dch polyme blend poly(-hydroxyl butyrat-co-hydroxyvalerat)(PHBV)/etyl xellulo vi dung mi l diclometan cc t lPHBV)/etyl xellulo 90/10 (k hiu a1), 80/20 (a2), 70/30(a3) v 60/40 (a4) [35]. Cc tc gi xy dng th ph thuc

gia nht ring ca dung dch polyme blend PHBV)/etyl xellulovo nng ca chng, t xc nh thng sb cho tng dungdch polyme blend PHBV)/etyl xellulo cc nng khc nhau(hnh II. 10). R rng l dung dch polyme blend PHBV)/etylxellulo cc t l khc nhau u c thng s b m tr polymeblend tl60/40, nng 2%. tlny, PHBV v etyl xellulo c tng tc vi nhau. Nh vy, polyme blend PHBV)/etyl


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xellulo l polyme blend khng tng hp, trpolyme blend tlPHBV)/etyl xellulo 60/40.

Nng (g/dl)

Hnh II.10. Thng sb theo nng ca cc dung dch polymeblend cc tlPHBV)/etyl xellulo ln lt l 90/10 (a1), 80/20 (a2),

70/30 (a3) v 60/40 (a4) [35].

Trong hn hp 3 thnh phn gm polyme A, polyme B v dungmi, hsHuggins K gm 3 thng stng tc: K1, K2 v K3 [36]:

1. Tng tc thu ng (hydrodynamic interaction) gia ccpolyme vi hstng tc K1:

(II.10)

2

2/12222

)][]([]][[)(2][][

1BA

BABA

wB

wA

wwBABKAKwBBKwAAKK

+++=


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Thi Hong68

Trong :

[A], [B]: nht thc ca cc dung dch polyme A vpolyme B; Av B: phn khi lng ca cc polyme A v polyme

B; KAv KB: hsHuggins tng ng vi cc dung dch polyme Av polyme B.

2. Shnh thnh cc phn tkp (double molecules) do tipxc gia cc i phn tca 2 polyme vi hstng tc K2 tngng:

(II.11)

Trong :

k: hng sv c thc bqua cho cc dung mi khng phncc. []1c tnh theo nht thc ca dung dch cc i phn tpolyme ring rv []2 l nht thc ca dung dch cha cc iphn tca hn hp 2 polyme.

3. Cc tng tc ht v y gia cc i phn tpolyme A v

polyme B vi hstng tc tng ng K3 = Nhvy, hsK= K1+ K2 + K3 K1+

K2 c bqua khi khng c cc lc ht c bit mnh giacc i phn tpolyme chng c thtp hp li v cc nng dung dch nh. Khi :

= K - K1

> 0:2 polyme A v polyme B ho trn vi nhau; < 0:2polyme A v polyme B khng tng hp.

Bng II.4 trnh by nht ring, cc gi trb, b v ca dungdch polyme blend metylmetacrylat-co-axit metacrylic (MMA-MAA)/PS cha 2,6% mol sunfonat trung ho magie (2,6MgSPS) cctlkhc nhau (dung mi 1,4 -dioxan, 25oC). Cc gi trb > 0 v> 0 cho thy MMA-MAA v 2,6 MgSPS ho trn tt vi nhau mi tlMMA-MAA/2,6 MgSPS trong 1,4 -dioxan.

)][]([][ 122

=

kK


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Bng II.4. nht ring, cc gi trb, b v ca dung dch polymeblend MMA-MAA/2,6 MgSPS [36].

TlMMA-MAA/2,6MgSPS

[A](dL/g)

b b

1/0 0,580 0,111 - -

0,25/0,75 0,282 0,148 0,060 1,468

0,50/0,50 0,419 0,187 0,022 0,596

0,75/0,25 0,282 0,343 0,503 3,752

0/1 0,504 0,169 - -

Trong bng II.5 l nht ring, cc gi tr b, b v cadung dch polyme blend metylmetacrylat-co-axit metacrylic(MMA-MAA)/PS cha 2,6% mol sunfonat trung ho km(2,6ZnSPS) cc t l khc nhau (dung mi 1,4 -dioxan, 25oC).Cc gi trb < 0 v < 0 chra tng tc y gia cc i phn tca MMA-MAA v 2,6ZnSPS. Do , MMA-MAA v 2,6ZnSPSkhng tng hp mi t l MMA-MAA/2,6ZnSPS trong 1,4 -

dioxan.

Bng II.5. nht ring, cc gi trb, b v ca dung dch polymeblend MMA-MAA/2,6ZnSPS [36].

TlMMA-MAA/2,6ZnSPS

[A]

(dL/g)b b

1/0 0,580 0,111 - -

0,25/0,75 0,461 0,090 - 0,152 - 0,0180,50/0,50 0,407 0,094 - 0,176 - 0,014

0,75/0,25 0,401 0,043 - 0,463 - 0,477

0/1 0,518 0,253 - -


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Thi Hong70

Khi nghin cu cc gi trb v ca dung dch polyme blendmetylmetacrylat-co-axit metacrylic (MMA-MAA)/PS cha 2,6%mol sunfonat trung ho mangan (2,6 MnSPS) cc t l 75/25;50/50 v 25/75 trong dung mi 1,4 - dioxan, cc tc ginhn thy,dung dch polyme blend MMA-MAA/2,6 MnSPS c cc gi trb< 0 v < 0 cc t l75/25 v 50/50. iu chra tng tcy gia cc i phn t ca MMA-MAA v 2,6 MnSPS, do MMA-MAA v 2,6 MnSPS khng tng hp cc t lni trn.Ngc li, dung dch polyme blend MMA-MAA/2,6 MnSPS tl25/75 c gi trb > 0 v > 0. Ngha l, t lny, xut hintng tc ht gia cc i phn tca MMA-MAA v 2,6 MnSPSnn MMA-MAA v 2,6 MnSPS tng hp mt phn vi nhau. Nhvy, phthuc vo tlMMA-MAA/2,6 MnSPS m MMA-MAA

v 2,6 MnSPS c thtng hp mt phn hoc khng tng hp.Nhvy, phng php xc nh nht ca dung dch polyme

blend v cc thng stng tc b v gia cc polyme l phngphp quan trng nh gi s ho trn v tng hp gia ccpolyme trong h.

II.4. Phng php da vo m men xon ca polyme blendtrng thi nng chy

M men xon trng thi nng chy (melt torque) ca mt polymehay hn hp cc polyme c quan h cht ch vi nht chytng i (relative melt viscosity) ca polyme hay hn hp ccpolyme (polyme blend). S ph thuc m men xon (M) capolyme hay polyme blend vo tc trn (S) trng thi nng chytrong thit blu bin sdng r to trn nhsau [37]:

M = CoSb

(II.12)

Trong :

Co - hng sph thuc vo hnh dng (geometry) thit b; b -hng sc trng cho polyme nng chy.

Trong hu ht cc trng hp, thlogarit m men xon (M)ca polyme blend nng chy v logarit tc trn (S) l mt ngthng v dc b c xem nh tng ng vi ch sn trongnh lut nng lng:


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= Kn (II.13)

Trong :

- ng sut trt; - tc trt; K - hng s t lxc nhmt dng vt liu nng chy v c tnh ton theo nh lutnng lng.

Cc thng snhng sut trt , tc trt v nht chytng i c xc nh bng cch thay cc gi trn, m men xonv tc trn vo cc biu thc sdng cho cc xi lanh ng trc vbin i cho vt liu chy khng l tng nhdi y:

(II.14)

(II.15)

= 1/ 1 (II.16)

Trong :

Ri, Re v Rm: ng knh trong, ng knh ngoi v ngknh trung bnh ca xi lanh

h: chiu di ca xi lanhCn cvo biu thc trn ta thy nht chy tng i ca

polyme blend lun t lthun vi m men xon trng thi nngchy ca polyme blend.

Kho st sbin i m men xon ca polyme blend trngthi nng chy l mt trong nhng phng php ng tin cy nh gi s tng tc ca cc polyme, nht l cc polyme c kh

hRM

m

2

11 2

=

)(

2/2/2/2

11 n

e

n

i

n

m

RRnR

S

=


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Thi Hong72

nng phn ng. y l c s don s tng hp v khngtng hp ca cc polyme. Ngi ta theo di sbin i m menxon ca mt khi lng hay thtch mu nghin cu c tnhton cc thi im trn khc nhau ti mt nhit tng i nnh v tc r to trn khng i. Cc thit b trn ni c sdng phbin nht nghin cu m men xon ca polyme blendl Haake Torque Rheometer, Haake Rheomixer, Brabender [37-39].

Theo nguyn l chung, khi trn hp 2 polyme A v B, nuchng khng c cc tng tc c bit v khng c khnng tnghp vi nhau th gi tr m men xon ca polyme blend A/B nnh sau khi nng chy hon ton. Nu gia 2 polyme A v B-co-Choc 2 polyme A v B-g-C c tng tc, m men xon ca polymeblend A/B-C c xu hng bin i khng n nh v cao hn gi trm men xon ca polyme blend A/B cng mt thi im trnnng chy. c bit, nu xy ra phn ng ho hc gia polyme Av copolyme B-C (phn C trong copolyme B-C phn ng vipolyme A) to thnh cc copolyme khi hoc copolyme ghp tich (in-situ) A-C th m men xon ca hn hp polyme c xuhng tng t ngt v copolyme ny s ng vai tr ca chttng hp cho polyme blend A/B-C. Trong trng hp ny, 2polyme tng hp mt phn vi nhau nh phn ng ho hc -tng hp nh phn ng hay tng hp phn ng (reactive

compatibility).Trong cng trnh nghin cu tnh cht lu bin v khnng

gia cng ca polyme blend PP/EPDM trn thit btrn ni Haake190oC (cao hn nhit nng chy ca polyme nn l PP) vithi gian trn 10 pht v tc trn 60 vng/pht, M. A. L.Manchado, J. Biagiotti v cng s cho thy m men xon (Mx)ca polyme blend PP/EPDM l mt hm ca hm lng EPDM.Cc gi tr m men xon cc t l PP/EPDM khc nhau uthp hn gi trm men xon tnh theo l thuyt cng mt tl

(theo quy tc cng l ng nt lin trn hnh II.11) [40]. Rrng l PP v EPDM l 2 polyme khng tng hp do 2 polymekhng c cc tng tc c bit.


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[EPDM] (%)

0 20 40 60 80 100 120

Mx

(N.m

)

5

10

15

20

25

30

Hnh II.11. Sthay i m men xon (Mx) ca polyme ble

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