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Some features of nonequilibrium heterophase copolycondensation
0082-39501811112761-08507.50[0
Polymer Science U.S.S.R. Vol. 23, 1~o. 11, pp. 2751-2758, 1981 Printed in Poland
O 1982 Pergamon Press Ltd.
SOME F E A T U R E S OF N O N E Q U I L I B R I U M HETEROPHASE COPOLYCONDENSATION* V. A. VASXEV, T. M. GOOIASHVlI,I, B. D. LAvalmmx, S. V. VINOGRADOVA a n d V. V. KORSHAK A. N. Nesmeyanov Hctero-organie Compounds Institute, U.S.S.R. Academy of Sciences
(Received 30 July 1980) A s t u d y has been made of the influence of reaction conditions on the composition and microstructure of the products of acceptor-catalytic copolyesterification of terephthalic acid dichloride with bis-(4-hydroxy-3-chlorophenyl)-2,2-propane (diehlorodiane) and hexaxaethylene glycol in the presence of triethylamine. I t was found that. features of copolymer formation b y nonequilibrium copolycondensation in homophase and heterophase systems differ. Light is shed on the influence of t h e reaction medium affecting copolymer structure under heterophase copolycondensation conditions. Structurally diverse copolymers are obtainable b y varying the initial monomer concent r a t i o n in the heterophase system.
DATA reported in the literature relate to features of the formation of macromolecules of mixed polymers under conditions of equilibrium polycondensatioI1 in melts [1, 2] and nonequilibrium polycondensation in solutions [3-7]. Our aim in the present instance was to investigate the extent to which reaction conditions influence the composition and microstructure (formation) of copolymers prepared by nouequilibrium copolycondensation in heterophase systems. The study objects were copolyesters prepared by acceptor-catalytic copolyesterification of terephthalic acid dichloride (intermonomer) with bis(4-hydroxy-3-chlorophenyl)-2,2-propane (dichlorodiane) and hexamethylene glycol (comonomers) in the presence of triethylamine. Copo]ymers formed in the synthesis separate out of the reaction solution xHO--(CH~)6--OH C I C - - ( f - - ~ - - C C 1 + (i - - x ) H O - - A r - - O H II ~ Ih O O
2(C,Hs),N --2(CzH,)aN-HCI
. . . . O - - i r O - - C - - ~/fl--~--C--OArO . . . . II ~ II O 0 .... OhrO--C-- x/~/--C--
tl
0
~
It
O(CH2)eO . . . .
(aca)
(acb)
O
..... O(CH2).O--C--O--C--O(CH2).O ii
.
0
0
* Vysokomol. soyed. A28: No. 11, 2537-2543, 1981. 2751
....
(bcb),
2752
V.A.V.~s~v • CI N
CH3 . /
e~ a/.
CI
CH3 The relative amounts of triads aca, acb and bcb in the copolymers were d e t e r m i n e d b y h i g h r e s o l u t i o n 1H N M R [4, 8]. The oopolycondensation was carried out in binary mixtures of organic solvents, making it possible to vary the properties of the reaction medium, and particulary its ability to cause precipitation of the copolymers from solution, and also swelling of the copolymers. Starting materials and solvents were purified b y methods described in literature and their constants agreed with d a t a in the literature. Copolycondensation was carried out in a single stage for 1 hr, varying the order in which initial reagents were introduced into the reaction zone. To a solution of diols and terephthalic acid dichloride, t r i e t h y l a m i n e was added rapidly (in 1-2 scc) (method B), or to a solution of diols and triethylamine was added, in the course of 15 rain, a solution of the dichloride (method A) using t h e micropump t y p e automatic metering equipment (MS-706 type, produced in CzSSR). The molar ratio of the dichlorodiane, hexamethylene glycol, dichloride and t r i e t h y l a m i n e was (~ 5 : 0.5 : 1 : 3. The copolyvonden~at~on as conducted in acc~rdanc~ with meShod A . To a solution of 0.296 g ((~0025 mole) of hexamethylene glycol, ~0745 g (~0025 mole) of dichlorodiane and 2.1 m l ((~0150 mole) of t r i e t h y l s m i n e in 20 ml of an acctone-n-heptane mixture {50 : 50 vol. ~o) was a d d e d at 30 ° in the course of 15 rain a solution of 1.016 g (0.0050 mole) of terephthalic acid dichloride in 5 ml of t h e above solvent system. Copolymer precipitated in 1 hr and was filtered, washed with methanol and t h e n with distilled water to obtain a negative test result for chloride ions with silver nitrate, after which it was again washed with methanol a n d dried a t 40-60 ° (1.3-~6 kPa) for 15-20 hr. The resulting copolyester (87~/o yield) had ~red=40 1./kg and Kin=0"27). I n the case of incomlpcte precipitation of copolymer from tho reaction solution the filtrate was decanted into 200 ml of methanol, the copolymer was filtered, and t r e a t e d in accordance with the above-described procedure. The cited viscosities of solutions of 0.05 g of t h e copolymcrs in 10 ml of tetrachloroe t h a n e were measured at 25 ° . The high resolution 1H NMR spectra were taken (Perkin-Elmer spectrometer t y p e R-32, operating frequency 90 M:Hz) at 100 ° in tetrachloroethane. The microhcterogeneity factor Km a n d block length of the copolymers were calculated b y standBxd formulae [5]. In calculating Km and t h e block lengths we took account of the overlap of quadruplet (heterotriad) side signals with singlets (homotriad). To allow for this overlap Km values based on the results o f integration of the 1H ~ spectra were multiplied b y a correction factor, and block lengths were divided b y this factor. The correction factor dctermmed b y us for a spectrometer operating at 90 Mttz, using a speciMly synthesized model compound (mcthylphenyl terephthalate) was 1-19. According to published d a t a the correction factor for a spectrometer operating at 100 ~ is I. 18 [9]. To verify t h a t the copolycondensation products were in fact copolymers, and not a mechanical mixture of homopolymers, we carried out a spcctroturbidimetrie t i t r a t i o n of solutions of the copolymer, homopolymer (dichlorodiaae polyterephthalate) and an equimolar (on t h e basis of 1 unit) miTture of homopolymers. W e prepared from t h e specimens under s t u d y dichloreethane solutions of equal concentration, and their t i t r a t i o n was carried o u t at 20 ° using two different precipitants: b i n a r y mixtures of acetone and n-heptane (25 : 75 eel. ~/o) and of dichloroctl,~, ,rod n-heptanc 25 : 75 eel. %).
Some features of nonequilibrium heterophase copolycondensation
2753
The turbidity spectra were recorded on a l~itachi (Japan) spectrophotometer, wavelength interval 400-600 nm, with an average rate of recording over a period of 1.5-2.0 rain. On the basis of the spectra we plotted the turbidity of the system against the volume fraction of precipitant. The results show that whatever type of precipitant is used the titration processes are entirely different for the copolyterephthalate of dichlorodiane and hcxamethylene glycol and the polyterephthalate of dichlorodiane and mixed polyterephthalates of dichlorodiane and hexamethylene glycol. I t is therefore fair to say that the products are true copolymers, and not a mixture of homopolymers. To determine degrees of swelling, copolyester spechnens (0.10-0.15 g) were placed i~l a glass vessel with a porous bottom, and were covered with solvent. After retention for 30 mhl in the solvent excess of the latter was removed by centrifuging at 5000 rev.#nin for 5 rain. Swelling calculations were based on the weight increment [10].
I n the case of the homophase single-stage nonequilibrium copolycondensat i o n a g r a d u a l i n t r o d u c t i o n of i n t e r m o n o m e r into t h e r e a c t i o n zone ( m e t h o d A) is a n e c e s s a r y condition for t h e f o r m a t i o n of b l o c k c o p o l y m e r s [5, 7]. T o d e t e r m i n e h o w f a r t h e t i m e t a k e n in a d d i n g t h e i n t e r m o n o m e r (the dichloride) to t h e com o n o m e r (diols) solution influences t h e s t r u c t u r e of t h e resulting c o p o l y m e r in t h e h e t e r o p h a s e process t h e a c c e p t o r - c a t a l y t i c c o p o l y c o n d e n s a t i o n w a s carried o u t in b i n a r y m i x t u r e s o f a c e t o n e a n d n - h e p t a n e ( 5 0 : 5 0 vol.~o ) a n d of toluene a n d n - h e p t a n e (50 : 50 vo].°//o).
It is seen from Fig. 1 that if the whole of the terephthalic dichloride solution is rapidly (in the course of several seconds) added to a solution of diols and t r i e t h y l a m i n e , t h e c o p o l y m e r h a s a Km v a l u e a p p r o x i m a t i n g u n i t y , i.e. close Km 1.0Km
1"3
®
0"6
2
®
0.9
1
0"2 ~×--x--3 I
6
I
f
18 T[rne , rn(n FIo. 1
I
I
3O
0.3' I
I
I
I
50 I00 n-I-lepfene >vol. % FzG. 2
I~Q. 1. Dependence of Km of the eopolyester on thne taken to add the terephthalie acid dichloride to a solution of dichlorodiane, hexamethylene glycol and triethylamine: 1, 2--heterophase eopolycondensation in binary equivolume systems acetone-n-heptane (1) and toluene-n-heptane (2); 3--homophase copolycondensation in dichloroethane [5]. FIo. 2. Dependence of dichlorodiane copolyterephthalate and he~rnethylene glycol on composition of the reaction medium: 1, 9 -- acetone-n-heptane; 3-- dichloroethane-n-heptane; 4--toluene-n-heptane. Copolymers were prepared by methods A (1) and B (2-4).
2754
V.A.
VASNEV et al.
to a level corresponding to a statistical distribution of chain units. I f the time taken to feed the dichloride solution into the reaction solution is increased, the value of Km is reduced, and in the final analysis reaches its limiting value. Limiting values of Km for the copolymers indicate that the latter are block copolymers. "[NleLUEI~-CE OF T H E N A T U ' I : ~ O F T H E ORGA_N~C M E D I U M O:N T H E C O M P O S I T I O I ~ A N D STRUCTt/M,E OF COPOLYMERS PREPARED
B Y C O F O L Y C O N I ) E N S A T I 0 1 q OF T E R E P H T H A L I C
I)ICHLORIDE
WITB~
DICH_LO:ROI)IAlqE A N D H E X A M . E T H Y I ~ E N E G L Y C O L
3opoly- I Experin~ent No
Organic m e d i a *
es~ser
I t/red,
yield,
1./kg
Nac
/~be
0.56 0.73 0"66 0-57 0-67
0.44 0.27 0.34 0.43 0.33
0.53 0.52 0.51 0.50 0.58
0.47 0.48 0.49 0.50 0-42
rise
~e
Km
8.4 21.0 11-8 9.3 4.2
6.5 7.6 5-5
0.27 0.19 0.26
7.1
0.25
2.1
0.73
1.7 1.8 1.7 2.3 2.9
1.5 1.7 1.6 2-3 2.0
1.26 1.14 1.24 0.88 4~83
% Methol Acetone : n-heptane [ Acetone : dichloroethane [ Dioxan : n-heptane I Dichloroethane : n-heptane Toluene : n - h e p t a n e
87 77 84 90 56
A¢ 40 61 77 61 44
Method B t 6 7 8 9 10
Acetone : n-heptane Acetone : dichloroethane Dioxan : n-heptane Dichloroethane: n-heptane Toluene : n - h e p t a n e
95 89 89 94 70
29 21 37 68 30
* 50 : 50 vol. %. t The dichloridesolution (1 mole/L)was added over a 15 min period to the solution of diols and triethylamine. A f t e r mixing the solutions the dichlorideconcentration was 0.20 mole/I. $ Initial dichloride concentration 0.20 mole/1.
A sinfilar dependence was previously observed for the homophase aceeptorcatalytic copolyesterification (Fig. 1. curve 3). It should, however, be noted t h a t if the molar concentrations of dichlorodiane terephthalate (Nac) and hexamethylene glycol terephthalate (Nbc) units were practically equal, then Nae is higher than Nbc in the copolymer obtained in a heterophase system (see Table, experiments I, 5). In the light of the data obtained it was desired that the composition and structure of the copolymers should be investigated as a function of the volume ratio of solvents in the binary systems. The results are presented in Fig. 2. It was found that the microstructure of the copolymers prepared in an acetone-n-heptane mixture by method A scarcely varies with the composition of the mixture (Fig. 2, curve 1). It follows from the fact that Kin=0"3 that block copolymers are formed. I f the process is conducted in line with method B the composition of the binary mixtures has a marked effect on the copolymer
Some features of nonequilibrium heterophase copolycondesation
2755,
microstructure, and the shape of curves 2-4 in Fig. 2 is determined by the nature of the organic medium. On investigating the composition of the copolyesters it was found that most of them prepared in the various reaction media by method A are enriched in the number of dichlorodiane terephthalate units ac. In the copolymers prepared by method B the number of ac and bc units are generally about equal (see Table). In earlier work it was found that under conditions of homophase nonequilibrium copolycondensation (method B) the use of solvents that have markedly dissimilar properties (dichloroethane and dioxan) has practically no effect on the statistical structure of the resulting dichlorodiane-hexamethylene glycol copolyterephthalates, whose Km values are respectively 1-12 and 1.09 [5, 11]. These results show that there are differences in the mechanisms of formation of copolymers by nonequilibrium copolycondensation in homo- and heterophase systems. Among the main reasons for the difference in the mechanisms of copolymer microstructure formation in the nonequilibrium copelycondensation processes in homo- and heterophase systems is, apparently, the fact that in the case of the heterophase copolycondensation the organic media differ in their ability to precipitate polymers from solution and to cause swelling of tim latter, i.e., in the final analysis, the media differ in their influence on the chain propagation steps. To verify this assumption we carried out a set of investigations of the solvents and of the solvent mixtures. A study of the turbidity spectra showed that the order of decreasing precipitating capacity for the acetone-n-heptane system (we give the volume ratios of the solvents) is as follows: 25 : 75, 100 : 0, 50 : 50, 75 : 25 (swelling of the copolymers is practically identical in all these mixtures). Thus with a volume fraction of precipitant ?=0.45 turbidities of the system (cm -1) in the corresponding order are 2 . 5 > 1 . 4 > 0 . 6 > 0 . 1 . On comparing these data with the results of synthesis of copolyesters in the same mixtures it was found t h a t an increase in the precipitating power of the binary system causes a reduction in the level of Km of the copolymers (Fig. 3). On the basis of these results the following mechanism is proposed for copolymer formation in a heterophase system by method B. The addition of triethylamine to a solution of the comonomers and intermonomer is followed by a position where preferentially the more active diol (bisphenol) initially enters into the reaction. The resulting oligomeric products separate out of solution to an extent that is proportionate to the precipitating power of the medium. Chain propagation of this comonomer continues in the precipitated swollen polymer, whereas hexamethyleae glycol terephthalate fragments begin precipitating at later stages of the process. Because of this the share of the mixed acb triad and accordingly Km values of the copolymers are reduced as the precipitating power of the medium increases.
2756
V.A. V A ~ ' v
~
~.
I n view of this we surmise t h a t ir~creased ability of the medium to cause swelling of the polymer, while the high precipitating power of the medium is preserved, will result in copolymers having longer blocks in the chain, since conditions more conducive to further chain propagation are created in the highly swollen precipitated oligobisphenol terephthalate. I t was found as a result of these investigations t h a t the ability of the dichloroethane-n-heptane and toluene-n-heptane systems to cause swelling of the copolymer greatly exceeds the ability of the acetone-n-heptane system. As one would expect, this meant t h a t more scope for change in the copolymer microstructure was created by using the toluene-n-heptane and dichloroethanen-heptane systems for the copolycondensation (see Fig. 2, curves 3, 4). I t is seen from the results discussed above t h a t in the case of the heterophase copolycondensation (in contradistinction to the homophase process) the nature of the reaction medium influences the structure of the copolymers. THe heterophase process results in block copolymers in cases where all the monomers are in the reaction zone at the outset, as one finds with method B. I n the homophase process the distribution of units in copolymers prepared under these conditions approximates to a statistical distribution [5, 11]. In view of ~he findings outlined above the process of siDgle-stage copnlycondensation was carried out in various types of organic media (Fig. 4) to shed
1"q ®
Km
"c', cm-I
1"5 I'1
1"0
I
04
.
~5 I
25
75 A cefone, vol. %
FzG. 3
I
0"1
I
0.3 c~ mole/l.
Fza. 4
~'xG. 3. Plot of dependence of Km of the copolyterephthalate of dichlorodiane and hexamethylene glycol (1) and of the precipitating power of the medium (2) on the composition of the acetene-n-heptane system (v--turbidity when 7=0-45). l~xG. 4. Plots of Km of copolyterephthalates of diehlorodiane and hexamethylene glycol vs. terephthalic acid dichloride concentration. Copolymers were prepared in an acetone-n-heptane system (50 : 50 vol. %) using methods A (1) and B (2), and aeetone-n-heptane (25 : 75 vol. ~o) with method B (3) and diehloroethane--n-heptane (25 : 75 vol. %) with method B (4).
Some features of nonequilibrium heterophase copolycondensation
~2757
light on the extent to which the concentration of the starting reactants influences t h e composition and structure of the copolymers. It was found that Km values of the copolymers are lower when the copolycondensation takes place in the acetone-n-heptane system (50:50 v o l . ~ ) with concentration of the dichloride increasing from 0.05 to 0-30 mole/1. (see Fig. 4, curves 1, 2). Whereas for method B the reduction in Km is slight (from 1.37 to 1.22), for method A it is considerable (from 0.76 to 0.27). Investigation of the copolymer compositions showed that for method A and also B a reduction in the dichloride concentration is accompanied by enrichment of the copolyesters with dichlorodiane terephthalate units, and, in the case of method A, the degree of enrichment is quite marked. Thus on reducing the dichloride concentration from 0.30 to 0.05 mole/l. Nac/Nbc is increased from 0 . 5 6 : 0.44 to 0.90 : 0.10. It was desired to compare the effect of the concentration of starting materials on the composition and structure of the copolymers obtained in binary mixtures of acetone and n-heptane (25:75 vol.°/o) and dichloroethane and n-heptane (25:75 vol.% ) having a marked precipitating ability but differing quite considerably in their ability to cause swelling of the polymer. Thus the swelling of the copolymer with Kin----0"27 and r/red---~40 1./kg in the systems examined were respectively 0.50 and 0.85 g/g. It was found that in an acetone-n-heptane mixuture (25 : 75 vol. ~/o)Km decreases monotonically from 1.44 to 0.85 (Fig. 4, curve 3) as the dichloride concentration in increased from 0.05 to 0.30 mole/1, i.e. copolymers of structurally very different types were obtained in this medium by varying the monomer concentrations. The position is altogether different when the copolycondensation is carried out in a mixture of dichloroethane and n-heptane (25 : 75 vol.°/o): the swelling in this system is more marked than in the acetone-n-heptane system. Irrespective of the concentration of the starting materials block copolymers with Kin~ 0"80 are obtained in all cases. It appears that the type of relationship is also influenced by the fact that one of the comonomers (hexamethylene glycol) is only sparingly soluble in the above solvent system. Thus it is seen that block copolymers are obtainable in heterophase systems (as distinct from the homophase ones) by varying the concentration of the initial monomers. Translated by R. J. A. H E N R Y
REFERENCES 1. R. YAMADERA and M. MURANO, J. Polymer Sci. 5, A - l : No. 9, 2259, 1967 2. T. S. lgHltAMOVA, Ya. G. URMAN, O. A. MOCHALOVA, F. M. MEDVEDEVA and I. Ya. SLONIM, Vysokomol. soyed. A10: 894, 1968 (Translated in Polymer Sci. U.S.S.R. 10: 4, 1040, 1968) 3. V. V. KORSHAK, V. A. VASNEV, S. V. VINOGRADOVA, P. O. OKULEVICH and Yu. L PERFILOV, Bold. Akad. N a u k SSSR 204: No. 5, 1129, 1972
2758
G. V. SHAT~LOV eJ a/.
4. V. V. KORSHAK, S. V. VINOGRADOVA, N. O. OKULEVICH, Yu. I. PERFILOV, V. A . VASNEV and E. I. FEDIN, Izv. Akad. Nauk SSSR, Seriya khimich., No. 7, 1629, 1972 5. V. A. VASNEV and S. I. KUCHANOV, Uspekhi khimii 42: No. 12, 2194, 1973 6. I. H. MACKEY, V. A. PATTISON and J. A. PAWLAK, J. Polymer Sci., Polymer Chem. Ed. 16: 1~o. 11, 2849, 1978 7. V. V. KORSHAK, S. V. VINOGRADOVA, V. A. VASNEV, Yu. I. PERFILOV and P. O. OKULEVICH, Vysokomol. soyed. A16: 2456, 1974 (Translated in Polymer Sci. U.S.S.R. 16: 11, 2852, 1974) 8. J. C. BOLLINGER, J. Macromolee. Sci. 16: C, No. 1, 23, 1977-78 9. E, V. GOUINLOCK, R. A. WOLFE and J. C. ROSENFELD, J. Appl. Polymer Sci. 20: No. 4, 949, 1976 10. S. V. ROGOZHJ[N, V. A. DAVANKOV, S. G. VYRBANOV and V. V. KORSHAK, Vysokomol, soyed. A10: 1277, 1968 (Translated in Polymer Sei. U.S.S.R. 10: 6, 1480, 1968) 11. V. A. VASNEV, Issledovaniye v oblasti aktseptorno-kataliticheskoi polieterifikatsii: Dis. n a soisk, uch. st. dokt. khim. n a u k (Studies in the Field of Accepter-c~atalytic Polyesterification: Discussion relating to applications for Chem. Sci. degree (Doctorate). p. 332, INEOS, Akad. Nauk SSSR, Moscow, 1975
Polymer ScienceU.S.S.R. Vol. 23, No. 11, pp. 2758-2766,1981 Printedin Poland
0032-3950/81/112758-09507.50/0 1982 PergamonPress Ltd.
THE HYDRODYNAMIC PROPERTIES OF SOLUTIONS OF CARBOCHAIN POLYMERS CONTAINING THE INDAZOLE RING* G. V. SHAT~LOV, Yr.. N. Pozr~cA, B. I. MrKHA~T'EV, S. A. PREOB~AZH~NSX~ and O. V. VOISHCHEVA Lenin Comsomol State University, Voronezh
(Recei,ved 11 August 1980) The Mark-I-ISuwink constants and macromolecular dimensions have been determined from the viscometrie and light scattering data for polyvinylindazole carboxylic esters. The equilibrimn flexibility parameters were investigated for the polymer chains. Values obtained for effective dipole moments /~e~f az~d for correlation parameters g point to intramolecular interactions detel~nined by the structure of polymer chain units.
APART from data on products containing imidazole and pyrazole rings [1, 2] little in;formation is available on the hydrodynamic properties of earboehain polymers based on unsaturated azole derivatives [1, 2]. To shed light on the properties of polyalkenylazoles differing as to the structure of the elementary * Vysokomol. soyed. A28: 1~o. 11, 2544-2550, 1981.
Polymer Science U.S.S.R. Vol. 23, 1~o. 11, pp. 2751-2758, 1981 Printed in Poland
O 1982 Pergamon Press Ltd.
SOME F E A T U R E S OF N O N E Q U I L I B R I U M HETEROPHASE COPOLYCONDENSATION* V. A. VASXEV, T. M. GOOIASHVlI,I, B. D. LAvalmmx, S. V. VINOGRADOVA a n d V. V. KORSHAK A. N. Nesmeyanov Hctero-organie Compounds Institute, U.S.S.R. Academy of Sciences
(Received 30 July 1980) A s t u d y has been made of the influence of reaction conditions on the composition and microstructure of the products of acceptor-catalytic copolyesterification of terephthalic acid dichloride with bis-(4-hydroxy-3-chlorophenyl)-2,2-propane (diehlorodiane) and hexaxaethylene glycol in the presence of triethylamine. I t was found that. features of copolymer formation b y nonequilibrium copolycondensation in homophase and heterophase systems differ. Light is shed on the influence of t h e reaction medium affecting copolymer structure under heterophase copolycondensation conditions. Structurally diverse copolymers are obtainable b y varying the initial monomer concent r a t i o n in the heterophase system.
DATA reported in the literature relate to features of the formation of macromolecules of mixed polymers under conditions of equilibrium polycondensatioI1 in melts [1, 2] and nonequilibrium polycondensation in solutions [3-7]. Our aim in the present instance was to investigate the extent to which reaction conditions influence the composition and microstructure (formation) of copolymers prepared by nouequilibrium copolycondensation in heterophase systems. The study objects were copolyesters prepared by acceptor-catalytic copolyesterification of terephthalic acid dichloride (intermonomer) with bis(4-hydroxy-3-chlorophenyl)-2,2-propane (dichlorodiane) and hexamethylene glycol (comonomers) in the presence of triethylamine. Copo]ymers formed in the synthesis separate out of the reaction solution xHO--(CH~)6--OH C I C - - ( f - - ~ - - C C 1 + (i - - x ) H O - - A r - - O H II ~ Ih O O
2(C,Hs),N --2(CzH,)aN-HCI
. . . . O - - i r O - - C - - ~/fl--~--C--OArO . . . . II ~ II O 0 .... OhrO--C-- x/~/--C--
tl
0
~
It
O(CH2)eO . . . .
(aca)
(acb)
O
..... O(CH2).O--C--O--C--O(CH2).O ii
.
0
0
* Vysokomol. soyed. A28: No. 11, 2537-2543, 1981. 2751
....
(bcb),
2752
V.A.V.~s~v • CI N
CH3 . /
e~ a/.
CI
CH3 The relative amounts of triads aca, acb and bcb in the copolymers were d e t e r m i n e d b y h i g h r e s o l u t i o n 1H N M R [4, 8]. The oopolycondensation was carried out in binary mixtures of organic solvents, making it possible to vary the properties of the reaction medium, and particulary its ability to cause precipitation of the copolymers from solution, and also swelling of the copolymers. Starting materials and solvents were purified b y methods described in literature and their constants agreed with d a t a in the literature. Copolycondensation was carried out in a single stage for 1 hr, varying the order in which initial reagents were introduced into the reaction zone. To a solution of diols and terephthalic acid dichloride, t r i e t h y l a m i n e was added rapidly (in 1-2 scc) (method B), or to a solution of diols and triethylamine was added, in the course of 15 rain, a solution of the dichloride (method A) using t h e micropump t y p e automatic metering equipment (MS-706 type, produced in CzSSR). The molar ratio of the dichlorodiane, hexamethylene glycol, dichloride and t r i e t h y l a m i n e was (~ 5 : 0.5 : 1 : 3. The copolyvonden~at~on as conducted in acc~rdanc~ with meShod A . To a solution of 0.296 g ((~0025 mole) of hexamethylene glycol, ~0745 g (~0025 mole) of dichlorodiane and 2.1 m l ((~0150 mole) of t r i e t h y l s m i n e in 20 ml of an acctone-n-heptane mixture {50 : 50 vol. ~o) was a d d e d at 30 ° in the course of 15 rain a solution of 1.016 g (0.0050 mole) of terephthalic acid dichloride in 5 ml of t h e above solvent system. Copolymer precipitated in 1 hr and was filtered, washed with methanol and t h e n with distilled water to obtain a negative test result for chloride ions with silver nitrate, after which it was again washed with methanol a n d dried a t 40-60 ° (1.3-~6 kPa) for 15-20 hr. The resulting copolyester (87~/o yield) had ~red=40 1./kg and Kin=0"27). I n the case of incomlpcte precipitation of copolymer from tho reaction solution the filtrate was decanted into 200 ml of methanol, the copolymer was filtered, and t r e a t e d in accordance with the above-described procedure. The cited viscosities of solutions of 0.05 g of t h e copolymcrs in 10 ml of tetrachloroe t h a n e were measured at 25 ° . The high resolution 1H NMR spectra were taken (Perkin-Elmer spectrometer t y p e R-32, operating frequency 90 M:Hz) at 100 ° in tetrachloroethane. The microhcterogeneity factor Km a n d block length of the copolymers were calculated b y standBxd formulae [5]. In calculating Km and t h e block lengths we took account of the overlap of quadruplet (heterotriad) side signals with singlets (homotriad). To allow for this overlap Km values based on the results o f integration of the 1H ~ spectra were multiplied b y a correction factor, and block lengths were divided b y this factor. The correction factor dctermmed b y us for a spectrometer operating at 90 Mttz, using a speciMly synthesized model compound (mcthylphenyl terephthalate) was 1-19. According to published d a t a the correction factor for a spectrometer operating at 100 ~ is I. 18 [9]. To verify t h a t the copolycondensation products were in fact copolymers, and not a mechanical mixture of homopolymers, we carried out a spcctroturbidimetrie t i t r a t i o n of solutions of the copolymer, homopolymer (dichlorodiaae polyterephthalate) and an equimolar (on t h e basis of 1 unit) miTture of homopolymers. W e prepared from t h e specimens under s t u d y dichloreethane solutions of equal concentration, and their t i t r a t i o n was carried o u t at 20 ° using two different precipitants: b i n a r y mixtures of acetone and n-heptane (25 : 75 eel. ~/o) and of dichloroctl,~, ,rod n-heptanc 25 : 75 eel. %).
Some features of nonequilibrium heterophase copolycondensation
2753
The turbidity spectra were recorded on a l~itachi (Japan) spectrophotometer, wavelength interval 400-600 nm, with an average rate of recording over a period of 1.5-2.0 rain. On the basis of the spectra we plotted the turbidity of the system against the volume fraction of precipitant. The results show that whatever type of precipitant is used the titration processes are entirely different for the copolyterephthalate of dichlorodiane and hcxamethylene glycol and the polyterephthalate of dichlorodiane and mixed polyterephthalates of dichlorodiane and hexamethylene glycol. I t is therefore fair to say that the products are true copolymers, and not a mixture of homopolymers. To determine degrees of swelling, copolyester spechnens (0.10-0.15 g) were placed i~l a glass vessel with a porous bottom, and were covered with solvent. After retention for 30 mhl in the solvent excess of the latter was removed by centrifuging at 5000 rev.#nin for 5 rain. Swelling calculations were based on the weight increment [10].
I n the case of the homophase single-stage nonequilibrium copolycondensat i o n a g r a d u a l i n t r o d u c t i o n of i n t e r m o n o m e r into t h e r e a c t i o n zone ( m e t h o d A) is a n e c e s s a r y condition for t h e f o r m a t i o n of b l o c k c o p o l y m e r s [5, 7]. T o d e t e r m i n e h o w f a r t h e t i m e t a k e n in a d d i n g t h e i n t e r m o n o m e r (the dichloride) to t h e com o n o m e r (diols) solution influences t h e s t r u c t u r e of t h e resulting c o p o l y m e r in t h e h e t e r o p h a s e process t h e a c c e p t o r - c a t a l y t i c c o p o l y c o n d e n s a t i o n w a s carried o u t in b i n a r y m i x t u r e s o f a c e t o n e a n d n - h e p t a n e ( 5 0 : 5 0 vol.~o ) a n d of toluene a n d n - h e p t a n e (50 : 50 vo].°//o).
It is seen from Fig. 1 that if the whole of the terephthalic dichloride solution is rapidly (in the course of several seconds) added to a solution of diols and t r i e t h y l a m i n e , t h e c o p o l y m e r h a s a Km v a l u e a p p r o x i m a t i n g u n i t y , i.e. close Km 1.0Km
1"3
®
0"6
2
®
0.9
1
0"2 ~×--x--3 I
6
I
f
18 T[rne , rn(n FIo. 1
I
I
3O
0.3' I
I
I
I
50 I00 n-I-lepfene >vol. % FzG. 2
I~Q. 1. Dependence of Km of the eopolyester on thne taken to add the terephthalie acid dichloride to a solution of dichlorodiane, hexamethylene glycol and triethylamine: 1, 2--heterophase eopolycondensation in binary equivolume systems acetone-n-heptane (1) and toluene-n-heptane (2); 3--homophase copolycondensation in dichloroethane [5]. FIo. 2. Dependence of dichlorodiane copolyterephthalate and he~rnethylene glycol on composition of the reaction medium: 1, 9 -- acetone-n-heptane; 3-- dichloroethane-n-heptane; 4--toluene-n-heptane. Copolymers were prepared by methods A (1) and B (2-4).
2754
V.A.
VASNEV et al.
to a level corresponding to a statistical distribution of chain units. I f the time taken to feed the dichloride solution into the reaction solution is increased, the value of Km is reduced, and in the final analysis reaches its limiting value. Limiting values of Km for the copolymers indicate that the latter are block copolymers. "[NleLUEI~-CE OF T H E N A T U ' I : ~ O F T H E ORGA_N~C M E D I U M O:N T H E C O M P O S I T I O I ~ A N D STRUCTt/M,E OF COPOLYMERS PREPARED
B Y C O F O L Y C O N I ) E N S A T I 0 1 q OF T E R E P H T H A L I C
I)ICHLORIDE
WITB~
DICH_LO:ROI)IAlqE A N D H E X A M . E T H Y I ~ E N E G L Y C O L
3opoly- I Experin~ent No
Organic m e d i a *
es~ser
I t/red,
yield,
1./kg
Nac
/~be
0.56 0.73 0"66 0-57 0-67
0.44 0.27 0.34 0.43 0.33
0.53 0.52 0.51 0.50 0.58
0.47 0.48 0.49 0.50 0-42
rise
~e
Km
8.4 21.0 11-8 9.3 4.2
6.5 7.6 5-5
0.27 0.19 0.26
7.1
0.25
2.1
0.73
1.7 1.8 1.7 2.3 2.9
1.5 1.7 1.6 2-3 2.0
1.26 1.14 1.24 0.88 4~83
% Methol Acetone : n-heptane [ Acetone : dichloroethane [ Dioxan : n-heptane I Dichloroethane : n-heptane Toluene : n - h e p t a n e
87 77 84 90 56
A¢ 40 61 77 61 44
Method B t 6 7 8 9 10
Acetone : n-heptane Acetone : dichloroethane Dioxan : n-heptane Dichloroethane: n-heptane Toluene : n - h e p t a n e
95 89 89 94 70
29 21 37 68 30
* 50 : 50 vol. %. t The dichloridesolution (1 mole/L)was added over a 15 min period to the solution of diols and triethylamine. A f t e r mixing the solutions the dichlorideconcentration was 0.20 mole/I. $ Initial dichloride concentration 0.20 mole/1.
A sinfilar dependence was previously observed for the homophase aceeptorcatalytic copolyesterification (Fig. 1. curve 3). It should, however, be noted t h a t if the molar concentrations of dichlorodiane terephthalate (Nac) and hexamethylene glycol terephthalate (Nbc) units were practically equal, then Nae is higher than Nbc in the copolymer obtained in a heterophase system (see Table, experiments I, 5). In the light of the data obtained it was desired that the composition and structure of the copolymers should be investigated as a function of the volume ratio of solvents in the binary systems. The results are presented in Fig. 2. It was found that the microstructure of the copolymers prepared in an acetone-n-heptane mixture by method A scarcely varies with the composition of the mixture (Fig. 2, curve 1). It follows from the fact that Kin=0"3 that block copolymers are formed. I f the process is conducted in line with method B the composition of the binary mixtures has a marked effect on the copolymer
Some features of nonequilibrium heterophase copolycondesation
2755,
microstructure, and the shape of curves 2-4 in Fig. 2 is determined by the nature of the organic medium. On investigating the composition of the copolyesters it was found that most of them prepared in the various reaction media by method A are enriched in the number of dichlorodiane terephthalate units ac. In the copolymers prepared by method B the number of ac and bc units are generally about equal (see Table). In earlier work it was found that under conditions of homophase nonequilibrium copolycondensation (method B) the use of solvents that have markedly dissimilar properties (dichloroethane and dioxan) has practically no effect on the statistical structure of the resulting dichlorodiane-hexamethylene glycol copolyterephthalates, whose Km values are respectively 1-12 and 1.09 [5, 11]. These results show that there are differences in the mechanisms of formation of copolymers by nonequilibrium copolycondensation in homo- and heterophase systems. Among the main reasons for the difference in the mechanisms of copolymer microstructure formation in the nonequilibrium copelycondensation processes in homo- and heterophase systems is, apparently, the fact that in the case of the heterophase copolycondensation the organic media differ in their ability to precipitate polymers from solution and to cause swelling of tim latter, i.e., in the final analysis, the media differ in their influence on the chain propagation steps. To verify this assumption we carried out a set of investigations of the solvents and of the solvent mixtures. A study of the turbidity spectra showed that the order of decreasing precipitating capacity for the acetone-n-heptane system (we give the volume ratios of the solvents) is as follows: 25 : 75, 100 : 0, 50 : 50, 75 : 25 (swelling of the copolymers is practically identical in all these mixtures). Thus with a volume fraction of precipitant ?=0.45 turbidities of the system (cm -1) in the corresponding order are 2 . 5 > 1 . 4 > 0 . 6 > 0 . 1 . On comparing these data with the results of synthesis of copolyesters in the same mixtures it was found t h a t an increase in the precipitating power of the binary system causes a reduction in the level of Km of the copolymers (Fig. 3). On the basis of these results the following mechanism is proposed for copolymer formation in a heterophase system by method B. The addition of triethylamine to a solution of the comonomers and intermonomer is followed by a position where preferentially the more active diol (bisphenol) initially enters into the reaction. The resulting oligomeric products separate out of solution to an extent that is proportionate to the precipitating power of the medium. Chain propagation of this comonomer continues in the precipitated swollen polymer, whereas hexamethyleae glycol terephthalate fragments begin precipitating at later stages of the process. Because of this the share of the mixed acb triad and accordingly Km values of the copolymers are reduced as the precipitating power of the medium increases.
2756
V.A. V A ~ ' v
~
~.
I n view of this we surmise t h a t ir~creased ability of the medium to cause swelling of the polymer, while the high precipitating power of the medium is preserved, will result in copolymers having longer blocks in the chain, since conditions more conducive to further chain propagation are created in the highly swollen precipitated oligobisphenol terephthalate. I t was found as a result of these investigations t h a t the ability of the dichloroethane-n-heptane and toluene-n-heptane systems to cause swelling of the copolymer greatly exceeds the ability of the acetone-n-heptane system. As one would expect, this meant t h a t more scope for change in the copolymer microstructure was created by using the toluene-n-heptane and dichloroethanen-heptane systems for the copolycondensation (see Fig. 2, curves 3, 4). I t is seen from the results discussed above t h a t in the case of the heterophase copolycondensation (in contradistinction to the homophase process) the nature of the reaction medium influences the structure of the copolymers. THe heterophase process results in block copolymers in cases where all the monomers are in the reaction zone at the outset, as one finds with method B. I n the homophase process the distribution of units in copolymers prepared under these conditions approximates to a statistical distribution [5, 11]. In view of ~he findings outlined above the process of siDgle-stage copnlycondensation was carried out in various types of organic media (Fig. 4) to shed
1"q ®
Km
"c', cm-I
1"5 I'1
1"0
I
04
.
~5 I
25
75 A cefone, vol. %
FzG. 3
I
0"1
I
0.3 c~ mole/l.
Fza. 4
~'xG. 3. Plot of dependence of Km of the copolyterephthalate of dichlorodiane and hexamethylene glycol (1) and of the precipitating power of the medium (2) on the composition of the acetene-n-heptane system (v--turbidity when 7=0-45). l~xG. 4. Plots of Km of copolyterephthalates of diehlorodiane and hexamethylene glycol vs. terephthalic acid dichloride concentration. Copolymers were prepared in an acetone-n-heptane system (50 : 50 vol. %) using methods A (1) and B (2), and aeetone-n-heptane (25 : 75 vol. ~o) with method B (3) and diehloroethane--n-heptane (25 : 75 vol. %) with method B (4).
Some features of nonequilibrium heterophase copolycondensation
~2757
light on the extent to which the concentration of the starting reactants influences t h e composition and structure of the copolymers. It was found that Km values of the copolymers are lower when the copolycondensation takes place in the acetone-n-heptane system (50:50 v o l . ~ ) with concentration of the dichloride increasing from 0.05 to 0-30 mole/1. (see Fig. 4, curves 1, 2). Whereas for method B the reduction in Km is slight (from 1.37 to 1.22), for method A it is considerable (from 0.76 to 0.27). Investigation of the copolymer compositions showed that for method A and also B a reduction in the dichloride concentration is accompanied by enrichment of the copolyesters with dichlorodiane terephthalate units, and, in the case of method A, the degree of enrichment is quite marked. Thus on reducing the dichloride concentration from 0.30 to 0.05 mole/l. Nac/Nbc is increased from 0 . 5 6 : 0.44 to 0.90 : 0.10. It was desired to compare the effect of the concentration of starting materials on the composition and structure of the copolymers obtained in binary mixtures of acetone and n-heptane (25:75 vol.°/o) and dichloroethane and n-heptane (25:75 vol.% ) having a marked precipitating ability but differing quite considerably in their ability to cause swelling of the polymer. Thus the swelling of the copolymer with Kin----0"27 and r/red---~40 1./kg in the systems examined were respectively 0.50 and 0.85 g/g. It was found that in an acetone-n-heptane mixuture (25 : 75 vol. ~/o)Km decreases monotonically from 1.44 to 0.85 (Fig. 4, curve 3) as the dichloride concentration in increased from 0.05 to 0.30 mole/1, i.e. copolymers of structurally very different types were obtained in this medium by varying the monomer concentrations. The position is altogether different when the copolycondensation is carried out in a mixture of dichloroethane and n-heptane (25 : 75 vol.°/o): the swelling in this system is more marked than in the acetone-n-heptane system. Irrespective of the concentration of the starting materials block copolymers with Kin~ 0"80 are obtained in all cases. It appears that the type of relationship is also influenced by the fact that one of the comonomers (hexamethylene glycol) is only sparingly soluble in the above solvent system. Thus it is seen that block copolymers are obtainable in heterophase systems (as distinct from the homophase ones) by varying the concentration of the initial monomers. Translated by R. J. A. H E N R Y
REFERENCES 1. R. YAMADERA and M. MURANO, J. Polymer Sci. 5, A - l : No. 9, 2259, 1967 2. T. S. lgHltAMOVA, Ya. G. URMAN, O. A. MOCHALOVA, F. M. MEDVEDEVA and I. Ya. SLONIM, Vysokomol. soyed. A10: 894, 1968 (Translated in Polymer Sci. U.S.S.R. 10: 4, 1040, 1968) 3. V. V. KORSHAK, V. A. VASNEV, S. V. VINOGRADOVA, P. O. OKULEVICH and Yu. L PERFILOV, Bold. Akad. N a u k SSSR 204: No. 5, 1129, 1972
2758
G. V. SHAT~LOV eJ a/.
4. V. V. KORSHAK, S. V. VINOGRADOVA, N. O. OKULEVICH, Yu. I. PERFILOV, V. A . VASNEV and E. I. FEDIN, Izv. Akad. Nauk SSSR, Seriya khimich., No. 7, 1629, 1972 5. V. A. VASNEV and S. I. KUCHANOV, Uspekhi khimii 42: No. 12, 2194, 1973 6. I. H. MACKEY, V. A. PATTISON and J. A. PAWLAK, J. Polymer Sci., Polymer Chem. Ed. 16: 1~o. 11, 2849, 1978 7. V. V. KORSHAK, S. V. VINOGRADOVA, V. A. VASNEV, Yu. I. PERFILOV and P. O. OKULEVICH, Vysokomol. soyed. A16: 2456, 1974 (Translated in Polymer Sci. U.S.S.R. 16: 11, 2852, 1974) 8. J. C. BOLLINGER, J. Macromolee. Sci. 16: C, No. 1, 23, 1977-78 9. E, V. GOUINLOCK, R. A. WOLFE and J. C. ROSENFELD, J. Appl. Polymer Sci. 20: No. 4, 949, 1976 10. S. V. ROGOZHJ[N, V. A. DAVANKOV, S. G. VYRBANOV and V. V. KORSHAK, Vysokomol, soyed. A10: 1277, 1968 (Translated in Polymer Sei. U.S.S.R. 10: 6, 1480, 1968) 11. V. A. VASNEV, Issledovaniye v oblasti aktseptorno-kataliticheskoi polieterifikatsii: Dis. n a soisk, uch. st. dokt. khim. n a u k (Studies in the Field of Accepter-c~atalytic Polyesterification: Discussion relating to applications for Chem. Sci. degree (Doctorate). p. 332, INEOS, Akad. Nauk SSSR, Moscow, 1975
Polymer ScienceU.S.S.R. Vol. 23, No. 11, pp. 2758-2766,1981 Printedin Poland
0032-3950/81/112758-09507.50/0 1982 PergamonPress Ltd.
THE HYDRODYNAMIC PROPERTIES OF SOLUTIONS OF CARBOCHAIN POLYMERS CONTAINING THE INDAZOLE RING* G. V. SHAT~LOV, Yr.. N. Pozr~cA, B. I. MrKHA~T'EV, S. A. PREOB~AZH~NSX~ and O. V. VOISHCHEVA Lenin Comsomol State University, Voronezh
(Recei,ved 11 August 1980) The Mark-I-ISuwink constants and macromolecular dimensions have been determined from the viscometrie and light scattering data for polyvinylindazole carboxylic esters. The equilibrimn flexibility parameters were investigated for the polymer chains. Values obtained for effective dipole moments /~e~f az~d for correlation parameters g point to intramolecular interactions detel~nined by the structure of polymer chain units.
APART from data on products containing imidazole and pyrazole rings [1, 2] little in;formation is available on the hydrodynamic properties of earboehain polymers based on unsaturated azole derivatives [1, 2]. To shed light on the properties of polyalkenylazoles differing as to the structure of the elementary * Vysokomol. soyed. A28: 1~o. 11, 2544-2550, 1981.