POlymer Science U.S.S.R. Vol. 24, No. 1, pp. 158-164, 1 9 8 2 0082-3950/821010158-07507.50[0 Printed in Poland O 1982 Pergamon Prem Ltd.

THE SYNTHESIS AND PROPERTIES OF ALIPHATIC-AROMATIC BLOCK COPOLYESTERS*

N. G. C~SXUs~Kn~A, L. B. SoxoT.ov, V. S. NAVMov, T. F. Sm~OVA and N. N. Zn~GALOVA

All-Union Synthetic Resin .l~eseareh Institute

(Received 29 September 1980)

Aliphatie-aromatic block copolyesters have been synthesized from diphenylol- propane, iso- and terephthalyl chlorides and various bifunctional aliphatie oligoether- glycols over a wide range of composition. The results of an investigation of the mecha- nical properties and solubility are given for the block copolyesters. Features of their phase state have been investigated by various methods (thermomeehanical, differen- tial-thermal, dielectric and X-ray methods). Properties of the block copolyesters may be controlled within wide limits (properties ranging from thermoplastics to elastomers) by varying the chemical structure of the polymer chain.

T ~ synthesis and properties of polycondensation type block copolymers are currently of major interest to investigators. This interest is based on the significant range of applications of the copolymer, which are used as elastomers, and for various types of coatings as well as for porous films and membranes [1].

To synthesize the block copolyesters we used a method of emulsion poly- condensation tha t had previously been developed [2], and comprised t~,o stages.

In the first stage a macrodichloride is prepared by reacting an excess of a mixture of iso- (IPC) and terephthalyl chlorides (TPC) with an aliphatic oligo- etherglyco].

The second stage involves condensation of a macrodichloride, prepared under optimal conditions and a free mixture of 1-PC and TPC (which in some cases remains in the form of a melt) with diphenylolpropane (diane), so as to synthesize regular alternating block copolymers with varying block lengths or the macrodichloride is condensed with an oligoarylate so as to synthesize regular alternating block copolymers with blocks of constant length [3]. Oligo- arylates were prepared in the emulsion system THF-water from a mixture of IPC and TPC with an excess of diane amounting to 20 mole %. In so doing we synthesized oligoarylates with a degree of polycondensation ~ 10.

The solubility, mechanical properties and features of phase state were investi- gated for the synthesized copolymers. Some characteristics and properlies of the block copolyesters are given in Table 1.

* Yysokomol. soyed. A24: No. 1, 138-142, 1982.

158

Aliphatic-aromatic block Copolyesters 159,

TABLE 1. PROPERTIES OF ALIPHATIO-AROMATIC R E O ~ ALTERNATING BLOCK COPOLYESTERS

Conoentra- 1 Aliphatic block tion, mole %t ~]ln, dl/g a,, MPa ~, % T °

copolymers with varying block lengths PP~- 1

PPG-2

PPG-3

PBGA

PPG- 1

PP G - 3

Block 2 5

10 15 20 25

2 5

10 15 25

2 5

10 15 25

2 5

10 15 25 40

Block copolymers

20 I 40

0"95 0"92 0"88 0"96 0"52 0"57 0"90 1"08 1 "07 0"81 0.80 0.63 0-70 0.69 0-40 0-57 0.94 1-10 0-98 0.86 0.72 0.67

57 7 50 4 40 87 20 53 2.6 53

44 10 32 50 32 70 18 130 1.1 146 5.2 16 3.8 39 1.0 116

0.8 62 55 5O 35 40 160 25" 360 5 490 7 160

with constant block lengths 0.52 I 10.2 7.6 0-81 I 15 24

209 178 145 125 113

205 185 145 75 75

160 135 150 140 205 185 120 65 6o 50

120 160

The b lock copolyes ters dissolve read i ly in ch lor ina ted organic solvents such as m e t h y l e n e chloride, chloroform, t e t r ach lo roe thane and dichloroethane. I n t h i s w a y one can p r epa re film ma te r i a l s b y cas t ing a solut ion of p o l y m e r on a suppor t .

I f the composi t ion is changed there is a g r adua l t r ans i t ion in po lycondensa t ion t y p e b lock copolymers f rom proper t i es of one c o m p o n e n t to those of the o t h e r . The mechan ica l p roper t i es which m a y be va r i ed wi th in wide l imits b y a l ter ing the b lock copo lymer compos i t ion h a v e been t a b u l a t e d (Table 1). T h u s film s t r eng th var ies f rom 57 to 5 MPa, and the b reak ing e longat ion f rom 7 to 4 9 0 % respect ive ly . The sha rpes t increase in the b reak ing e longat ion occurs on using as the a l ipha t ic b lock an ol igoester glycol of po lybu ty leneg lyco l ad ipa t e wi th M----2000 (PBGA); the m o s t m a r k e d reduct ion in tensi le s t r eng th is obse rved on using as the a l ipha t ic b lock an ol igoether glycol of po lyoxypropy leneg lyco l wi th M = 3 0 0 0 (PPG-3).

The bes t and m o s t in te res t ing p roper t i es observed were those of the block copolyes ters in which the concen t ra t ion of ol igoester(ether)glycol is va r ied f r o m 10 to 25 mole %.

160 N. G. Cmzxtrsm~r~A e$ a/.

On comparing mechanical properties of the block copolymers differing in their polymer chain structure it was found that the regular alternating block ¢opolymers with blocks of constant length have properties differing markedly from those of the regular alternating block copolymers with blocks of varying length (Table 1).

Phase state investigations were carried out for the block copolymers with the a id of thermomeehanical, dielectric and differential-thermal methods.

~,% 5 q

3

20

1

0 qO 80 I20 T °

FIG. 1. Thermomechanical clucves for films of block copolyesters from PPG-3 (1, 3) and PBGA (2, 4, 5) on oligoetherglyeol concentrations: 10 (1, 2), 25 (3, 4) 40 mole ~/o (5).

Figure 1 and Table 1 give the results of thermomechanical investigations for block copolyesters of d~ffering composition. The analysis of thermomechanical curves of the block copolymers containing as the oligoetherglycol polyoxypro- pyleneglyeol with M-~1000 (PPG-1), 2000 (PPG-2) and PBGA in 2-40 mole % concentration represent a single-phase system characterized by a single :high- temperature transition (Fig. 1, curves 2, 4 and 5), i.e. the aliphatic block does not present a separate phase. I t should be noted, however, that the glass transition temperature of the block copolyesters falls with increasing concentration of the oligoetherglycol, apparently on account of the lat ter combining with polyarylate phase, and resulting in its plasticization

A heterophase divided structure, characterized by two glass temperatures, is observed solely for the block copolymer based on PPG-3 when the PPG-3 concentration is not less than 25 mole ~/o (Fig. 1, curve 3). However microphase separation is far from being complete in this ease since the glass temperature of the block copolyesters is significantly lower than tha t of the polyarylate block, whereas Tg the for oligoether glycol block is a little higher than tha t of pure oligoetherglycol {Tg for PPG --75°). I t is probable that interpenetration and a partia! compatibility of the polyarylate and oligoetherglycol components is reflected in this case.

The degree of dilution of the aromatic block by the oligoetherglycol increases

Aliphatic-aromatic block copolyesters 161

with increasing concentration of the latter, which is reflected in a reduction of T~ for the high-temperature transition of the block copolymers.

A DTA analysis of the block copolyesters shows that at various temperatures there are intervals in which their thermal capacities increase. Higher thermal capacities observed for the block copolyesters based on PPG-1 and PPG-3 at low temperatures are due to devitrifieation of oligoetherglycol microregions in the copolymers.

TABLE 2. T E M P E R A ~ S OF HEAT CAPACITY CHANGES

Oligoetherglycol concentration h~

the block co- polymer, mole,~o

2 5

10 15 25 40

Temperatures of heat capacity changes in block copolymers based o n

PPG- 1

--10 --27 - - 3 1

- - 4 0

- - 4 3 - - - 2 8

PPG-3

--60 - - 6 6 - - - 4 8

- - 6 5 - - - 5 5

- - 6 0 - - - 5 3

PBGA

- - 3 8 - - - 2 1

- - 3 9 - - - 6

- - 4 4 - - - 2 0

PBGA in concentrations exceeding 20 mole % forms a separate phase in the copolymers and may crystallize. Melting peaks appear at 42 and 47 ° for the block copolyesters containing 25 and 40 mole % PBGA respectively.

Phase state investigations based on measurement of dielectric properties helped to reveal the presence of oligoetherglycol microregions already where the aliphatic oligoetherglycol concentration in the system was 2 mole %.

I t is clear from temperature dependences of the dielectric loss tangent (Fig. 2) tha t there are two relaxation peaks for the block copolyesters under review. The size and temperature position of the high-temperature transition depend on the composition of the block copolymer. With a 25 mole % concentration of PPG-1 {Fig. 2a, curve 5) a marked increase in the magnitude of this maximum is observed. In the ease of the block copolyesters based on PPG-3 (Fig. 2b, curve 2) a low PPG-3 concentration is sufficient to increase tan ~ and displace the latter towards high temperatures. I t was found for the block copoiymers based of PBGA (Fig. 2c, curve 1) that the tan 5 maximum is displaced markedly towards higher temperatures and its size is increased. The size of the maximum is reduced in the case of a high PBGA concentration, and is displaced towards low tempera- tures, which is at tr ibutable to crystallization of the oligoetherglycol component (PGBA).

We conclude from these findings that the high temperature maximum whose magnitude is directly proportional to the amount of oligoetherglycol introduced, is at tr ibutable to separating oligoetherglycol phase. Moreover the completeness

162 1~. G. CB2EUSIIKINA et OZ.

of phase separation depends on the nature of the oligoetherglycol, and on its molecular weight.

Where the system is a single-phase one the high-temperature transition characterizes devitrification of amorphous phase of the polyarylate component diluted with an aliphatic oligoetherglycol, as is borne out by the X-ray struc- tural analysis. Irrespective of the polymer chain structure, diffractograms of the

~and.lO ~

6

a 5 q

h - ~ z 0 C 8031 2 1

I I I I -lqO -100 -60 -2.0 207.0 60 -qO 0 q O 80

7"

FIG. 2. Temperature dependence of tan 5 for films of block copolyesters with different oligoetherglycol concentrations (mole ~o): a--PPG-1; 1--0; 2--2; 3--10; 4--15; 5--25;

b--PPG-3: 1--0, 2--2; 3--5, 4--15; 5--25; v--PBGA: 1--15; 2--25; 3--40.

Aliphatic-aromatic Mock copolyesters 163

block copolyesters h a v e a b r o a d a m o r p h o u s halo a n d and ave rage i n t e r p l a n a r

spac ing of 4.65 A. W h e n the spec imens are sub jec ted to hea t t r e a t m e n t (a t a t e m p e r a t u r e 40 ° above the sof tening poin t for 1 hr) those plas t ic ized w i t h PPG-1 show bu t an insignif icant c rys ta l l iza t ion t e n d e n c y expressed b y the a p p e a r - ance of a discrete reflection wi th an i n t e r p l a n a r spac ing of 4.3/~ aga ins t a back - g round of an a m o r p h o u s halo.

The low t e m p e r a t u r e t r ans i t ion charac ter iz ing devi t r i f icat ion of the ol igoether- glycol componen t t akes place a t - -35 ° (PPG-3) in the case of the two-phase sys tem. F o r the b lock copolymers based on P B G A the low t e m p e r a t u r e t rans i - t ion m a y in the case of high P B G A concent ra t ions be the resul t of me l t ing of the ol igoetherglycol component .

Thus the resul ts of inves t iga t ions of block copolyesters p r epa red b y different m e t h o d s are m u t u a l l y in a g r e e m e n t and lead us to conclude t h a t m i c r o p h a s e sepa ra t ion t akes place in the sys t ems examined . The comple teness of this sepa- r a t i on depends on the composi t ion of the block co polyesters , on the chemical n a t u r e

of the ol igoethergJycol being used, and on i ts molecu la r weight .

The method outlined in [2] was used to synthesize the maerodichlorlde containing acid chloride endgroups.

The method of [4] was used to synthesize aliphatic aromatic block copolyesters. The logarithmic viscosity of 0"5~o solutions of the eopolymers was measured in phenol-

tetrachloroethane (60:40) solution. Viscosity measurements were performed at 25 ° in a V-PZh-2 viscosimeter, capillary diameter 0-73 ram.

Temperature transitions were investigated on a device for plotting thermomechazdea! curves, using the method of [5].

X-ray structural investigation of specimens was carried out on DRON-1 type equipment (Ni-filtered CuK a radiation).

Temperature transitions were determined from thermograms plotted on a differentia| mierocalorLmeter using the method of [6].

The breaking stress and breaking elongation were determined in line with GOST (State Standard) 14236-76.

Dielectric properties were investigated on TP-10C equipment (Takede Ricken Company) in a dry helium atmosphere in the interval -- 140-140 ° over a wide range of frequency, ushlg a standard method [7].

Starting materials. Bifunetional aliphatic oligoetherglycols containing O ~ endgroups:: PPG-1, OH group concentration 3.13%; PPG-2, O~[ group concentration 1.54%; PPG-3, OH group concentration 1.2%; PBGA, OH group concentration 1.75%.

IPC and TPC had m.p. 43.6 and 83 ° respectively; the diane --156 °. The moisture con- tent of THF did not exceed 0"05~o; NaOH and NaC1 were of pure grade and were used without furttmr purification.

Translated by R. J. A. HElVDRY

REFERENCES

1. L. Z. ROGOVINA, Uspekhi khimii 46: 10, 1871, 1977 2. N. G. CHEKUSHIKINA, Vysokomol. soyed. 22: 2688,

U.S.S.R. 22: 12, 2974, 1980) 3. P. M. VALETSI(I'[~ Uspekhi khimii 48: 1, 75, 1979

1980 (Translated in Polymer Sci

164 E . R . BADAMSHINA. e$ al.

4. T. V. KUDIM, Vysokomol. soyed. A20: 1802, 1978 (Translated in Polymer Sci. U.S.S.R: 20: 8, 2023, 1978)

5. B. A. FOMENKO, Zavodsk lab. 34: 3, 359, 1968 6. G. M. P A L ~ , U.S.S.R. Pat discussion at Chemical Sci. Cand. Degree Competition,

p. 23, High Polymer Inst. Akad. ~auk Ukr. S.S.R., Kiev, 1975 7. V. S. DOMK1N, In: Efiry tsellyulozy (Cellulose Esters), p. 171, Vladimir, 1969

Polymer Science U.S.S.R. Vol. 24, No. 1, pp. 164-170, 1982 Printed in Poland

0032-3950/82/010164--07507.50/0 ©. 1982 Pergamon Press Ltd.

INVESTIGATION OF THE MECHANISM OF POLYPENTENAMER DEGRADATION IN THE PRESENCE OF METATHESIS CATALYSTS*

E. R. B ~ s m ~ A , G. I. Tn~oF~rEVA, Y r . V. KORSH~K, AL. AL. BER~r~, V. M. VDOVnV, ]). F. K~EPOV and S.-S. A. PAVLOVA

A. V. Topehiyev ~sti~ute of Petrochemical Synthesis, U.S.S.R. Academy of Sciences A. N. Nesmeyanov Tnstitute of Hetero-organie Compounds, U.S.S.R. Academy of Sciences

D. I. Mendeleyev Chemieotechnological Institute, Moscow

(Received 8 October 1980)

A ]YlWD method has been used to investigate the mechanism of degradative cyc- lization of unsaturated polymers in the presence of the catalytic system

CH,

WC1,-- (CHa)sSi / ~Si- - (CH,), \ /

C//,

taking polypentenamer as an example. I t was found that the process takes place by a random chain mechanism, one fragment being stable, and the other depolymerizing down to monomer. The fact that the initial concentration of the catalytic system appears to have no influence on the degradation points to slow initiation in this system. The ratio of the constant for chain transfer to polymer to that of depolymerization was found by experiment to be ktr/kd----5 X 10 -6 m3/mole.

S~.VER)m authors have shown t h a t an in t ramolecular react ion of metathesis of unsa tu ra t ed polymers under the act ion of tungs ten-conta in ing cata lys ts in dilute solutions leads to marked degrada t ion of the polymers and to format ion of a large number of low molecular cyclic oligomers [5-11]. In some cases reactions of degrada t ive cyelization of polyalkenamers lead to the format ion of cycloolefines,

* Vysokomol. soyed. A24: No. I, 143-148, 1982.