PVC

April 8, 2023April 8, 2023 PVCPVC 11

PVCPVC

n= 625 to 2700 (Mw = 39000-168000 g/mol)


Year 2000


Bahan MentahBahan Mentah

2224 H3HCCH2

CHClCHHClClCHCClHClCHCH 222222


Kandungan KlorinKandungan Klorin


Vinyl & FireVinyl & Fire

☺Kandungan ~ 50 % klorin Kandungan ~ 50 % klorin

☺Perangkap radikal, peracunan mekanisme apiPerangkap radikal, peracunan mekanisme api

~~~~~~~~ClHR~~~~~~~HXR Flame retardant

Bahan Bakar Hidrogen

Flame retardant fragment

Bahan Bakar, kekurangan hidrogen

☺ Karbon monoksidaKarbon monoksida

Hanya menyediakan setengah Hanya menyediakan setengah

bahan bakar daripada polimer lainnyabahan bakar daripada polimer lainnya


PolimerisasiPolimerisasi


radikal bebas radikal bebas



VCM vs. OksigenVCM vs. Oksigen

OO22 tidak diinginkan tidak diinginkan

OO22 R-O-O-R R-O-O-R' +' +VCM VCM

poli (vinil klorid poli (vinil klorid peroksidaperoksida

OO22 dideteksi , Kenapa? dideteksi , Kenapa?

VCM vs. NitrogenVCM vs. Nitrogen

NN22 larut dalam VCM larut dalam VCM

(Jadi, apa??) (Jadi, apa??) 1.1.2.2.

Bagaimana bisa kita bergerak monomer???Bagaimana bisa kita bergerak monomer???

Monomer digerakan oleh:Monomer digerakan oleh: PompaPompa Pemanasan Pemanasan GrafitasiGrafitasi

Pengangkutan monomerMenekan pembangunan



Suspensi polimerisasi banyak digunakan, Suspensi polimerisasi banyak digunakan, karena :karena :

1. Titik didih monomer yang rendah.1. Titik didih monomer yang rendah.

(Stabilitas PVC)(Stabilitas PVC)

2. PVC saling larut dengan monomer nya.2. PVC saling larut dengan monomer nya.


PVC solubility in its monomer PVC solubility in its monomer

PVC tidak larut dalam monomernya sendiri. PVC PVC tidak larut dalam monomernya sendiri. PVC sebagai endapan partikel kecil selama polimerisasi. sebagai endapan partikel kecil selama polimerisasi. Ini aglomerat yang struktur internal berpori.Ini aglomerat yang struktur internal berpori.

VCM ini cukup larut dalam PVC:VCM ini cukup larut dalam PVC: PVC melunak dengan monomer. PVC melunak dengan monomer. Tingkat polimerisasi VCM dalam partikel yang Tingkat polimerisasi VCM dalam partikel yang

bengkak secara substansial bengkak secara substansial lebih cepat lebih cepat dari laju dari laju polimerisasi dalam fase cair polimerisasi dalam fase cair (Mengapa?)(Mengapa?)


Kelarutan PVC dalam monomernyaKelarutan PVC dalam monomernya

Percepatan AutoPercepatan Auto

Seiring dengan peningkatan konversi Seiring dengan peningkatan konversi polimer Lebih polimer Lebih terbentuk terbentuk monomer Lebih mengalami monomer Lebih mengalami pembengkakan didalam polimerpembengkakan didalam polimer

For For long half-life initiatorlong half-life initiator, , ConversionR p

However, long half-life initiators are not used, so However, long half-life initiators are not used, so reaction acceleration tends to drop off as the active reaction acceleration tends to drop off as the active initiator is consumed.initiator is consumed.


Polimerisasi kinetikaPolimerisasi kinetika

Eksotermik: panas yang dihasilkan oleh reaksi

Panas total beban: panas aktual harus dihilangkan


berat molekulberat molekul

MMww of PVC is controlled by altering the of PVC is controlled by altering the

polymerization temperature, polymerization temperature, chain transfer to chain transfer to monomer controls the Mmonomer controls the Mww..

T ↑ MT ↑ Mww↓ (why?)↓ (why?)

Karena kenaikan suhu, meningkatkan laju perpindahan rantai lebih cepat daripada tingkat perambatan rantai.


MWDMWD

Isothermal Isothermal Narrow MWD Narrow MWD

Temperature ramped Temperature ramped Broad MWD Broad MWD

T

t


Polimerisasi Suhu ReaksiPolimerisasi Suhu Reaksi

Suhu Polimerisasi 50 Suhu Polimerisasi 50 C – 70 C – 70 CCT < 50 T < 50 C:C:

Tingkat Polimerisasi terlalu lambat dan MTingkat Polimerisasi terlalu lambat dan MWW terlalu tinggi.terlalu tinggi.

T > 70 T > 70 C: P terlalu tinggiC: P terlalu tinggi


Pemindah rantai untuk monomerPemindah rantai untuk monomer


Perpanjangan berat molekulPerpanjangan berat molekul

To produce high-MTo produce high-Mww PVC, there are two PVC, there are two

options:options:

1.1. Lower temperature (T<50Lower temperature (T<50C) C) BUT…BUT…

2.2. Add multifunctional monomer as di-allyl Add multifunctional monomer as di-allyl phthalate, phthalate, Be careful…Be careful…


Perpanjangan Berat MolekulPerpanjangan Berat Molekul

More challenging task…More challenging task…

To produce low-MTo produce low-Mww PVC, there are two options: PVC, there are two options:

1.1. Reduce temperature, BUT…Reduce temperature, BUT…

2.2. Use chain-transfer agentUse chain-transfer agent


StrukturStruktur

PVC memiliki struktur linierPVC memiliki struktur linier

PVC shows a tendency to add via syndiotacticPVC shows a tendency to add via syndiotactic

placement placement low crystallinity low crystallinity

Head to tail is most commonHead to tail is most common


PVC factsPVC factsTransport 7%

Building 60%

Other 5%

Electronics 8%

Consumer goods 10%

Packaging 10%

Annual demand close to 30 Mton

Annual growth of 4%

75% by suspension polymerization

Wide variety of applications


StabilityStability

PVC is the least stable polymer in commercial use.PVC is the least stable polymer in commercial use.PVC degrades as it is exposed to high temperatures, high PVC degrades as it is exposed to high temperatures, high

mechanical stress or ultraviolet (UV) light.mechanical stress or ultraviolet (UV) light.This may take place during processing, storage and This may take place during processing, storage and

utilization. utilization. Degradation causes discoloration, deterioration of Degradation causes discoloration, deterioration of

mechanical properties and lowering of chemical resistance. mechanical properties and lowering of chemical resistance. Degradation of polymer occurs by successive elimination of Degradation of polymer occurs by successive elimination of

HCl (dehydrochlorination) yielding polyenes. HCl (dehydrochlorination) yielding polyenes.


StabilitasStabilitas


StabilitasStabilitas

Stabilization mainly proceeds by the addition of Stabilization mainly proceeds by the addition of compounds as: metal oxides, carbonates, fatty acid compounds as: metal oxides, carbonates, fatty acid salts as well as HCl acceptors as ethylene oxide salts as well as HCl acceptors as ethylene oxide compounds. compounds.

These additives stabilize PVC by:These additives stabilize PVC by:

1. slowing down the dehydroclorination reaction.1. slowing down the dehydroclorination reaction.

2. absorption of the evolved HCl. 2. absorption of the evolved HCl.


C l

C l R C lStr

uctu

ral d

efe

cts

Chain branches

• Long chain branches (R > 4 C atoms)

• Short chain branches (R ≤ 4 C atoms)

Internal double bonds

Thermal stability

tertiary chlorine

allylic chlorine

Polymer microstructure


Stabilitas Stabilitas

Thermal stability decreases when monomer conversion Thermal stability decreases when monomer conversion increases (increases (WHY?WHY?))


PlasticizationPlasticization

It is defined as converting PVC, which is a rigid It is defined as converting PVC, which is a rigid polymer, to flexible PVC. polymer, to flexible PVC.

Plasticization improves flexibility by acting as an Plasticization improves flexibility by acting as an internal lubricant between PVC chains.internal lubricant between PVC chains.

For a plasticizer to be effective, it must be For a plasticizer to be effective, it must be thoroughly mixed and incorporated into the PVC thoroughly mixed and incorporated into the PVC polymer matrix.polymer matrix.



Plasticization theories:Plasticization theories:

Lubricating theoryLubricating theory: as the system is heated, the : as the system is heated, the plasticizer molecules diffuse into the polymer and plasticizer molecules diffuse into the polymer and weaken the polymer-polymer interactions (van der weaken the polymer-polymer interactions (van der Waals' forces). According to this theory the Waals' forces). According to this theory the plasticizer molecules act as shields to reduce plasticizer molecules act as shields to reduce polymer-polymer interactive forces and prevent the polymer-polymer interactive forces and prevent the formation of a rigid network.formation of a rigid network.



Plasticization theories:Plasticization theories:

Gel theoryGel theory: considers the plasticized polymer to be : considers the plasticized polymer to be neither solid nor liquid but an intermediate state, neither solid nor liquid but an intermediate state, loosely held together by a three-dimensional loosely held together by a three-dimensional network of weak secondary bonding forces. These network of weak secondary bonding forces. These bonding forces acting between plasticizer and bonding forces acting between plasticizer and polymer are easily overcome by applied external polymer are easily overcome by applied external stresses allowing the plasticized polymer to flex, stresses allowing the plasticized polymer to flex, elongate, or compress.elongate, or compress.


CopolymersCopolymers

¤ VCM does not copolymerize well. It has an unfavorable reactivity VCM does not copolymerize well. It has an unfavorable reactivity ratio with just about every other monomer except vinyl acetate ratio with just about every other monomer except vinyl acetate (VAC).(VAC).

¤ Because of the unfavorable reactivity ratios, making other Because of the unfavorable reactivity ratios, making other copolymers usually involves long reactions with slow metering of copolymers usually involves long reactions with slow metering of one of the monomers (the one that reacts fastest).one of the monomers (the one that reacts fastest).

¤ PVC is insoluble in the monomer and this produces the porous PVC is insoluble in the monomer and this produces the porous internal structure. One of the reasons for this insolubility is that internal structure. One of the reasons for this insolubility is that the polymer has a certain level of crystallinity the polymer has a certain level of crystallinity This produces a This produces a non-porous particle. non-porous particle.


CopolymersCopolymers

¤ most copolymers are made using microsuspension or emulsion most copolymers are made using microsuspension or emulsion methods , because these processes produce small particles that can methods , because these processes produce small particles that can be stripped of residual monomer.be stripped of residual monomer.

¤ Copolymers entangle and fuse at lower temperatures and flow Copolymers entangle and fuse at lower temperatures and flow more easily at lower melt temperatures, because they have low or more easily at lower melt temperatures, because they have low or no crystallinity. no crystallinity.

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PVC