The effect of plasticizers on polycarbonate structure

The effect of plasticizers on polycarbonate structure

2072 T.V. IKANINAet al. REFERENCES 1. S. ALEXANDER, J. Phys. 38: 8, 983, 1977 2. T. M. BIRSHTEIN and Ye. B. ZHULINA, Vysokomol. soyed. A25: 9, 1862,...

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2072

T.V. IKANINAet al.

REFERENCES 1. S. ALEXANDER, J. Phys. 38: 8, 983, 1977 2. T. M. BIRSHTEIN and Ye. B. ZHULINA, Vysokomol. soyed. A25: 9, 1862, 1983 (Translated in Polymer Sci. U S.S.R. 25: 9, 2165, 1983) 3. T. M. BIRSHTEIN and Ye. B. ZHULINA, Konformatsii makromolekul, svyazannykh s poverkhnostyami razdela (The Conformation of Macromoleeules Linked to Separation Surfaces). Pushchino, 1983 4. P. G. DE GENNES, Macromolecules 13: 5, 1069, 1980 5. P. G. DE GENNES, Idei skeihnga v fizike pohmerov (The Scahng Concept in Polymer Physics), Moscow, 1982 6. M. DAOUD, J. P. COTTON, G. JANNI,K, G. SARMA, H. BENOIT, R. DUPLESSIS, C, PICOT nad P. G. DE GENNES, Macromolecules 8: 5, 804, 1975 7. M. DAOUD and J. P. COTTON, J. Phys. 43: 3, 531, 1982 8. T. M. BIRSHTEIN, Vysokomol. soyed. A24: 10, 2110, 1982 (Translated in Polymer Sci U.S.S.R 24: 10, 2416, 1982 9. D. W. SCHAEFFER, J. F. JOANNY and P. PINCUS, Macromolecules 13: 5, 1280, 1980 10. F. BROCHARD and P. G. DE GENNES, J. Phys. Letters 40: 10, 339, 1979 11. L. TURBAN, J. Phys. 45: 2, 347, 1984 12. T. M. BIRSHTEIN, Ye. B. ZHULINA and O. V. BORISOV, Polymer 27: 7, 1078, 1986 13. Ye. B. ZHULINA and T. M. BIRSHTEIN, Vysokomol. soyed. B26: 10, 773, 1986 (Not translated in Polymer Sci. U.S.S.R.) 14. O. V. BORISOV, T. M. BIRSHTEIN and Ye. B. ZHULINA, Vysokomol so~ed. A29: 7, 1987 15. B. GALLO, ZhidkokrJstalhcheskll poryadok v polimerakh (Liquid Crystal Ordering in Polymers) p. 206, Moscow 1981

Polymer ScienceU,S S.R. Vol. 29, No 9. 2072-2077. 1987 Printed in Poland

0032-3950187 $10.00+.00 r~ 1988Pergamon Press plc

THE EFFECT OF PLASTICIZERS ON POLYCARBONATE STRUCTURE* T.V

IKANINA,

A. I. SUVOROVA and A. A. TAGER

A. M. Gorkii Urals State University (Received 24 March 1986)

The phase diagrams of the polycarbonate-dtbutyl phthalate and polycarbonate-pentachlorodiphenyl systems have been studied. It has been shown that pentachlorodiphenyl reduces the melting point of polycarbonate much more than dlbutyl phthalate does. When plasticizers are introduced neither the Bragg angle, corresponding to a maximum in the dlffraetogram nor the effective crystallite size are changed. Plasticlzers d]stributed in the amorphous polycarbonate regions promote additional crystalhzation of the polymer, which causes a contraction and disappearance of the convex part of the sorption isotherms and a decrease of the interdiffusion coefficient. * Vysokomol, soyed. A29; No. 9, 1888-1891, 1987.

Effect of plastic~zers on polycarbonate structure

2073

Trm antt-plastictzmg effect or the increase in modulus of a polymer when plasticizers are introduced is, as shown in [1], more pronounced with an amorphous polycarbonate (PC) than a crystalline one. To explain the role of the crystalline structure in the antiplasticizing effect, a detailed study was made of the effect of plasticizers on PC structure, which was assessed from X-ray studies of the plasticized system, determinations of d e n s i t y o f a m o r p h o u s a n d c r y s t a l l i n e s a m p l e s a n d s o r p t l o n o f c h l o r o f o r m v a p o u r by the latter PC w,th M = 4 - 7 x 104 based on 2,2-dl-4-hydroxyphenylpropane was used, repreclpltated from 7o~ /o solution in chloroform with excess ethanol. Amorphous and crystalline PC samples and also the plasticized systems were prepared by methods described in [1]. The pentachlorodlphenyl (PCD) and dlbutyl phthalate (DBP) plastlcizers were previously purified by fractional vacuum distillation. The phase diagrams of the polymer-plasticizer systems were constructed using the Alekseyev turbidity point method The heating and coohng of the samples was camed out at a rate of 2 deg/hr. A gravimetric variant of the segmented integral sorption method was used Measurements were made at 298°K on an apparatus, described earlier [2]. The sensltlVlty of the quartz spirals was (0-5-0 6) x 10 a m/kg. Diffractograms of the samples were obtained using the X-ray fluorescence dlffractometer DRF-2-0 in the 10-35 ° angle region, Co filtered by Fc with a wavelength of 2=0'1796 nm was used. The degree of X-ray crystalhmty X was defined as the ratio of the crystalline reflection areas in the 20= 15-30 ° region to the sum of the areas of crystalline and amorphous scattering [3, 4]. The effective crystalllte size L was calculated from the angular half width reflections from the formula K2 L = Bc - - o s O '

(l)

where p is the X-ray reflection widemng, 0 is the Bragg angle, K is a coefficient depending on crystalline form (K=0'9) [4]. The densities of amorphous, d., and of partly crystalhne samples, d, were determined by a flotation method [5]; aqueous potassium iodide was used as the flotation liquid. Two parallel measurements were made for each sample, with an error not exceeding 2 kg/m a The degree of crystallimty A was calculated from the formula [6, 7]_ d-da A - d~ - d , '

(2)

where dk ~s the density of a sample at the hmit of crystallization, which for PC was taken to be 1310 kg/m 3 [8], and for the plasticized systems was calculated from the formula 1 oJ2 cot . . . . ÷--. dk dtpc dl

(3)

Here dkFc IS the density of crystalline PC, d~ is that of the plasticizer o~2 and co~ are the proportions by weigth of polymer and plasticizer. It f o l l o w s f r o m Fig. 1, t h a t t h e p h a s e d i a g r a m s o f c r y s t a l h n e P C h a v e t h e l i q u i d u s c u r v e s h a p e s , a b o v e w h i c h t h e r e ts a r e g i o n o f h o m o g e n e o u s , s i n g l e - p h a s e solutions. Below the curves there are metastable regions, consisting of a solution and a crystalline p h a s e , t h e p r e s e n c e o f w h i c h was c o n f i r m e d b y p o l a r i z a t i o n m i c r o s c o p y a n d X - r a y analysis. H o w e v e r , t h e m a c r o l a m i n a t i o r t s o f t h e s e s y s t e m s d i d n o t r e s u l t f r o m t h e i r h i g h v i s c o s i t y b u t f r o m t h e c r y s t a l l i n e gels f o r m e d .

2074

T . V . IKANINAet al.

The limiting curve of the P C - D B P system is located above that of the P C - P C D system. This indicates that DBP promotes PC crystallization to a grater degree than does PCD. The phase eqttihbrlum data agree With the X-ray results for the plasticized systems. The diffractograms of crystalline PC in the P C - P C D and P C - D B P systems have a clear

,/

X/m,kg/k9 r,K 470

390 310

b

S I

I

o.z

06 FIG. 1

0.6t

sac

a

0.2

2

06

S

I

0.2

0.4

[

p,/p?

FIG. 2

FIG. 1. Phase diagrams of PC, plasticized with PCD (1) and DBP (2). FIG. 2. Isotherms of sorptlon of CF vapours at 293°K by crystalhne PC samples, plasticized with PCD (a) and DBP (b) with a volume proportion of plasticizer of (0=0 (•); 1 (2), 0 008 (3); 0 016 (4); 0 022 (5), 0 040 (6), 0 113 (7); 0-254 (8); 0 305 (9), 0 480 (10), and 0-597 (11)

maximum, corresponding to an angle of 20=29-5 °, the position of wtuch remains constant; only its intensity, 1, changes; as the PCD content increases, the magnitude of ! continuously falls; as the proportion of DBP by volume increases, I changes in an extreme fashion. The effective crystalline sizes, L, calculated from equation (2), amount to 29 nm and hardly depend on the content and nature of the plashcizer, which affects the degree of crystallization of the PC, as judged from the X-ray data and the density. It is clear from the Table that the degree of crystalhnity A determined by the 2 methods, differs by ca. 10 ~o which agrees with published data, is explained by the measurement of different physical characteristics. On introducing small amounts of plasticizer, X and A grow and attain constant values. DBP increases the degree of crystalllnity more than PCD does. The Table gives the mixed volumes ,4 V, representing the difference in volumes of the plasticized systems and the additive volumes, which were calculated from the densities given in the Table. It is evident that on mixing with both plasticizers, a contraction is observed. For the amorphous sample, the lfV value hardly depends on the nature of the plasticizer but for the crystalline samples, a greater contraction is observed on adding DBP than PCD. The isotherms for sorptlon of chloroform vapour (CF) m crystalhne PC samples, plasticized systems and plasticizers are given in Fig. 2. The PC isotherm has an S shape

2075

Effect of plasticizers on polycarbonate structure

I b

Mt/M.

3' 1

I

1

200

600

2OO

6OO t~/2 secT/2

FIG 3 Kinetic curves for integral sorptmn of CF by crystalline forms of PC, plasticized by PCD with a proportion by volume of plasticizer of 0-008 (a) and 0 480 (b) The relative vapour pressure of solvent pl/pt was 0-0 05 (1); 0-0 04 (1'), 0 05-0 15 (2); 0 04-0 12 (2'), 0 15-0 36 (3); 0 12-0 29 (3'); 0 36-0 58 (4); 0 67-0 81 (4'); and I)-74-0 87 (5)

with a convex initial section which ~s typical of polymers with an open packing [9]. On introducing the first portions of plasttclzer, the concave section disappears, indicating the contraction of the system. When the plasticizer content ~s further increased, the CF dissolves Ill the plasticizer, as a result of wlch the sorpttve capacity of the plasucized system grm~s DEGREE

OF

CRYSTALLINITY

System PC PC-PCD

PC-DBP

AND

Volume p l o p o m o n of plastmlzer 0 0 040 0 081 0-165 0 253 0 023 0 057 0-112 0 222

SPECIFIC

VOLUME

OF MIXING

j

PC-PCD

AND

PC-DBP

SYSTEMS

V, ma/kg

kg/m 3 1203 1226 1246 1285 1317 1204 1206 1209 1203

FOR

1226 1248 1266 1300 1328 1230 1239 1235 1223

crystalhne sample

amop~ hous sample

m

7 10 15 13 5 12 19 25

I n Fig. 3, k m e t i c s o r p t l o n c u r v e s a r e s h o w n f o r the P C - P C D

7 11 18 20 3 18 16 24

A,%

x,%

21 24 24 27 23 26 31 38 44

35 38 48 40 38 39 50 52 55

s y s t e m In t h e g e n e r a l l y

a c c e p t e d M , / M ~ = f ( t ) c o o r d i n a t e s , w h e r e Mt a n d M ~ are t h e a m o u n t s o f s o r b e d m a t e r i a l at t i m e t a n d at e q u i l i b r i u m r e s p e c t i v e l y . S i m i l a r results w e r e o b t a i n e d w i t h the PC-DBP

system. It f o l l o w s f r o m t h e F i g u r e t h a t at d i f f e r e n t r e l a t i v e v a p o u r pres-

sures, v a r i o u s t y p e s o f k m e t l c c u r v e s a r e f o u n d . T h u s at l o w r e l a t t v e v a p o u r p r e s s u r e s f o r the s a m e P C in p l a s t i c i z e d systems, b o t h p s e u d o - n o r m a l

and S-shaped kinetic

2076

T.V. IKANINAel al.

sorption curves are typical. At certain relative pressures, the greater the plasticizer content, the fewer the curves with maxima. According to published data [10], this is due to changes in polymer structure and in the sorption process and for PCs this is related to its crystallinity [6, 11]. - tog D [rn2/sec]

2

16 I

I

0.2

O.q

1

0-6 ~I

I~o. 4. Concentrationaldependence of the coefficient of mutual diffusionof CF for the crystalline systems PC--PCD (1) and PC.-DBP (2).

As described in [10], the coefficients of mutual diffusion D were calculated from the initial parts of the pseudo-normal curves and the final sections of the S-shaped kinetic curves, from the equation M,

(4)

4 f Dt ~

when 1 is the sample thickness. Besides this, the D values, depending on the CF concentration in the system, were obtained. In order to find a D value, independent of the CF concentration, the values of this concentration were extrapolated to zero. The relation of the D values, obtained by this method, to the proportion by volume of plasticizer is shown in Fig. 4. On introducing plasticizers, D passes through a minimum. The decrease in the mutual diffusion coefficient in the initial sorption stage is a result of contraction of the PC macromolecule, which completely agrees with the increase in the degree of crystallinity and magnitude of shrinkage. A further increase is due to intermixing of CP molecules throughout the plasticizer. In all composition ranges, the mutual diffusion coefficient of CF in the PC-PCD system is less than in the PC-DBP one, which evidently is due to the higher thermodynamic affinity of CF for DBP than for PCD. Therefore, the constancy of the Bragg angle, corresponding to a maximum on the diffractograms and the invariance of the crysta]lite sizes, indicate that the plasticizers do not penetrate into the crystalline PC regions. Being redistributed in the amorphous parts of the PC, they promote contraction of the system and additional crystallization of the polymer, as a result of which the degree of crystallinity grows. This leads to shrinkage, to disappearance of the concave parts of the sorption isotherms and a decrease in the mutual diffusion coefficient of CF in the plasticized system. Translated by C. W. C^Pr

Random copolymers of 3-iodo-9-N-vinyl carbazole and n-octyl methacrylate

2077

REFERENCES 1. A. I. SUVOROVA, T. V. IKANINA, A. A. TAGER and L. L. KALEGINA, Vysokomol soyed B27: 4, 256, 1985 (Not translated m Polymer Scl. U S.S R ) 2. V. S. BLINOV, Disc kand. khlm. nauk., 150 pp, Ural'skiJ gos. un-t, Sverdlovsk, 1985 3. A. GIN'YE, Rentgenografiya kristallov (X-ray Crystallography). 600 pp, Moscow 1961 4 M. A. MARTYNOV and K. A. VYILEGZHANINA, Rentgenografiya pohmerov (Radiography of Polymers). 96 pp, Moscow, 1972 5_ C. F. CULLIS, A. C. NORRIS and D. L. TRIMM, J. Phys. Scient. Instrurn. 3: 11, 911, 1970 6. J, P. MERCIER, G. GROENINCKX and M. LESNE, J. Polymer Scl., 16, 2059, 1967 7. L. Ya. TSVANKIN, Ents.klopedlya pollmerov, vol 3, p. 512, Moscow, 1977 8 A. PRIETZSCHK, Kolloid Z. 156: 1, 8, 1958 9. A. A. TAGER and M. V. TSILIPOTKINA, Uspekli khimli 47: 1, 152, 1978 10 A. Ya. MALKIN and A. Ye. CHALYKH, DJffuziya i vyazkost' pohmerov (Diffusion and V~scos~ty of Polymers). 303 pp, Moscow, 1979 11 R. P. KAMBOUR, F. E. KARASZ and V. H. DEANE, J Polymer Sci A-2, 4: 3, 327, 1986

Polymer ScmnceU_SS R Vol 29. No 9, pp. 2077-2082, 1987 Printed m Poland

0032-3950/87 $ I 0 00 + ,00 © 1988 Pergamon Press pie

THE THERMODYNAMICS OF THE RANDOM COPOLYMERS OF 3-IODO-9-N-VINYL CARBAZOLE AND n-OCTYL METHACRYLATE* V. P PRIVALKO, A. P, ARBUZOVA, N YE. ZAGDANSKAYA, S. P. PAS'KO and L. N. FEDOROVA Polymer Chemistry Institute, Ukrainian Academy of Sciences T. G Shevchenko State Umversity, Klev

(Recewed 26 March 1986) Heat capacity m the 130-480°K and specific volume in the 313-493°K temperature ranges and at pressures of 15-210 MPa were studied for the random copolymers of 3-iodo9-N-vinyl carbazole and n-vinyl methacrylate. Based on an analysis of the dependences of the glass point, the heat capaoty changes at this point and the parameters of the Slmki-Somchmskli equation of state, Jt has been concluded that substitution of a proton of the carbazole nucleus by Iodine causes some weakemng of intermolecular interaction, but thzs does not essentially affect the nature of the thermal mobihty of the macromolecule in a melt

IN THE P r i g o z h m m o d e l a n d also in the original models o f Flory, S l m k l - S o m c h i n s k i l a n d others, the chain structure o f p o l y m e r molecules was t ak en into a c c o u n t by a p h e n o m en o l o g i cal p a r a m e t e r C (i.e. by a n u m b e r o f external degrees o f f r eed o m ) , which * Vysokomol. soyed. A29: No 9, 1892-1896, 1987