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Photochemical degradation of polyarylates containing phosphorus
Photochemical degradation of polyarylates containing phosphorus 5. G. S. KOLESNIKOV and :No. l l , 1965 6. G. S. KOLESNIKOV and in Polymer Sci. U.S.S.R. 7. G. S. KOLESNIKOV and in Polymer Sci. U.S.S.R. 8. L. K. YARALOV and G. in Polymer Sci. U.S.S.R. 9. G. S. KOLESNIKOV and in Polymer Sci. U.S.S.R.
107
L. K. YARALOV, Avt. svid. 171562, 1963; Byull. izobretenii, L. K. YARALOV, Vysokomol. soyed. 7: 551, 1965 (Translated 7: 3, 610, 1965) L. K. YARALOV, Vysokomol. soyed. 8: 674, 1966 (Translated 8: 4, 740, 1966) S. KOLESNIKOV, Vysokomol. soyed, 8: 870, 1966 (Translated 8: 5, 956, 1966) L. K. YARALOV, Vysokomol. soyed. 7: 1807, 1965 (Translated 7: 10, 1990, 1965)
PHOTOCHEMICAL DEGRADATION OF POLYARYLATES CONTAINING PHOSPHORUS *t S. 1~. I~AFIKOV, S. V. VII~OGRADOVA, V. V. KORSHAK a n d Z. YA. FOMIlVA Institute for Elementary Organic Compounds, U.S.S.R. Academy of Sciences
(Received 15 September 1965)
IT ~AS been shown previously [1] that the introduction of sulphur into polyarylates increases their resistance to light both in solution in chloroform and also in the form of films. With the aim of further clarifying the possibility of creating polyarylates self-resistant to light-ageing, the effect of introducing phosphorus atoms into the polyarylate structure has been investigated in the present work. In the literature there is information about phosphorus-containing polyarylates based on resorcinol, 2,2,-di-(4-hydroxyphenyl)propane(diane), hydroquinone, and such acidic components as the acid chlorides of methylphosphinic and phenylphosphinic acid [2]. The polyarylate of diane with the hydroxide of bis-(p-carboxyphenyl) methylphosphine has been described [3]. Certain polyarylates based on phenolphthalein (PP), and on the acid chlorides of methylphosphonic acid (CMPA) and of the hydroxide of bis-(p-carboxyphenyl) methylophosphine (COCMP) have been synthesized and investigated in the present work. EXPERIMENTAL Initial substances. COCMP was obtained by the method described previously, and had constants in good agreement with the literature data [3]. CMPA was purified by distillation and had a melting point of 32-33°C (melting point according to the literature data, 33°C [4]). The melting point of the PP used was 261°C. * Vysokomol. soyed. A9: :No. 1, 98-102, 1967. ~f 94th Communication in the series "Heteroehain polyesters".
108
S . R . RAFIEOV et
al.
The synthesis of the hcmogeneons and of the mixed polyarylates containing phosphorus, based on PP and CMPA, COCMP and terephthalyl Chloride (TC) was carried out by a high temperature polycondensation in a Sovol medium, at a concentration of 0.6 mole/litre, with the simultaneous introduction of all the initial components into the reaction. The temperature conditions for the polycondensation were as follows: the reaction mass was heated from 100 to 220°C in 3 hr and then held at 220°C for 14 hr. At the end of the reaction, the reaction mass was dissolved in chloroform, precipitated with methanol, the precipitated polymer was filtered off and carefully washed with methanol, hot water, twice with methanol, and dried i n v a c u o at 2-3 mmHg at 60°C for 10 hr. The homogeneous polyarylate based on PP and CMPA was obtained by polycondensation in the melt. Initially, the reaction mass was heated in a current of nitrogen for 10 hr with a gradual increase in the temperature from 10 to 200°C, and then i n v a c u o (1 mmHg) at 220°C for 1 hr and at 250°C for 2 hr. The properties of the homogeneous and of the mixed polyarylates obtained are shown in Table 1. The photochemical degradation of the polyarylates 3 and 4, shown in Table 1, was investigated in 1 and 20% solutions, and in films. Cyclohexanono and chloroform were used as solvents. The solutions were irradiated at 20 4-2°C by a mercury-quartz lamp PRK-2, with a power of 400 watts. The duration of the irradiation was 10 hr. The change in the molecular characteristics of the polyarylates during irradiation was assessed from the viscosity of dilute solutions (1% and less) in the same solvent in which the irradiation had been carried out. In many experiments, the change in the optical properties of the polyarylates during irradiation was studied: in particular, the absorption spectrum in the ultraviolet and in infrared regions was determined. The determination of the end hydroxyl groups in the irradiated and unirradiated polyarylates by Verley's method was also carried out. The molecular weights of the polyarylate~ before and after irradiation was determined by the light-scattering method. Films of the polyarylates with a thickness of 404-5 ~ were irradiated in air by means of the PRK-2 lamp at 404-2°C for 10 hr. The resistance to light of the polyarylate films was assessed from the change in their strength properties during irradiation, as determined on a Polanyi apparatus.
RESULTS AND DISCUSSION As m a y be seen f r o m the d a t a p r e s e n t e d in Table 1, the p o l y a r y l a t e b a s e d on P P a n d COCMP (polyarylate 2) has a high softening point, w h i c h is h a r d l y red u c e d a t all w h e n 0.9 mole of the p h o s p h o r u s - c o n t a i n i n g dicarboxylic acid is replaced b y t e r e p h t h a l i c acid. P o l y a r y l a t e s f r o m P P a n d CMPA are less h e a t resistant a n d in this case s u b s t i t u t i o n o f 0.9 mole m e t h y l phosphinic acid for t e r e p h t h a l a t e causes a conside r a b l y increase in t h e softening t e m p e r a t u r e of the m i x e d polymer. P o l y a r y l a r e s 1, 3 a n d 4 are easily soluble in m a n y organic solvents, chloroform, eyclohexanone, c a r b o n tetrachloride, etc. The h o m o p o l y a r y l a t e 2 (based o n t h e arom a t i c p h o s p h o r u s - c o n t a i n i n g acid) is sparingly soluble in these solvents. T h e polya r y l a t e s 1 a n d 2, containing 8.20 a n d 5.35% p h o s p h o r u s , b u r n w i t h difficulty a n d are self-extinguishing w h e n t h e flame is r e m o v e d . F i g u r e 1 shows the change in the viscosity of solutions of the m i x e d p h o s p h o r u s containing p o l y a r y l a t e s a n d of the p o l y a r y l a t e P - 2 ( P P a n d terephthalie acid) d u r i n g their irradiation in 1 a n d 20% solutions in chloroform a n d cyclohexanone. I t is clear f r o m this Figure, t h a t w h e n 1% solutions of t h e p h o s p h o r u s - c o n t a i n i n g p o l y a r y l a t e s in chloroform are irradiatied, their viscosity falls only slightly (Fig.
Photochemical degradation of polyarylates containing phosphorus
109
la, curves 3, 4), whereas the viscosity of the solutions of polyarylate P-2 falls from 0.65 to 0-19 t h a t is, by 70% (Fig. la, curve 5). Different behaviour is observed when 1% solutions of the polyarylates in cyclohexanone are irradiated. As m a y be seen from Fig. la (curves 3', 6', 5'), b
~sp
oj
f
a 0.6
o
o~, ~r
o
o3r
0.*
0"2 0
Z~' 0.2 $
T/me,hi,
/0
~ne, hp
FIG. 1. Change in the specific viscosity during irradiation of (a) 1%, and (b) 20%, solutions of polyarylates in chloroform and cyclohexanone. The numbers on the curves correspond to the numbers of the polymers in Table 1: 3, 4, 5--irradiated in chloroform; 3', g', 5'--irradiated in cyclohexanone. the viscosity of polyarylate solutions markedly falls, especially during the initial period of irradiation, but after about 5 hr, it remains practically unchanged. Data obtained during the irradiation of 20 ~/5 solutions of the polyarylates in chloroform and in cyclohexanone are shown in Fig. lb. I t m a y be seen from them t h a t no reduction in the viscosity of the solutions is observed during irradiation of polyarylates 3 and 4 in chloroform. The molecular weight of the polymer and the hydroxyl group equivalent thus remain practically unchanged (Table 2). When polyarylate P-2 is irradiated under similar conditions an increase in the molecular weight of 40% is observed (although the specific viscosities of the solutions thus undergo a scarcely significant increase). I t m a y be concluded from the data presented that no crossli~king of the polyarylate chains takes place during the irradiation of concentrated solutions of the polyarylates 3 and 4 in chloroform or in cyclohexanone. CO and CO 2 were observed in the gaseous products of the degradation of polyarylates 3 and 4 in solution, as had been the case during the light-ageiag of solutions of polyarylates P-2 and of polyarylates containing sulphur [1]. This forms a basis for proposing t h a t the general course of degradation in solutions, and also in the condensed phase, evidently consists in the rupture of an ester bond, predominantly of the lactone ring, with the formation of free radicals, secondary reactions of the free radicals leading to the release of CO and COm. However, as distinct from the process of light ageing in films, in ~solutions the recombination of radicals and the formation of branched and crosslinked structures is difficult. In cyclohexanone, as in cases previously investigated, there
S. R. R~r~ov et aL
II0
evidently takes place a reaction between the aroxyl radicals formed and the solvent, and this leads to a certain increase in the hydroxyl group concentration and even to free phenols to the mechanism: --Re. +RH->--ROH-t-R. Absorptions bands in the 1630-1640 cm -1 region were observed in the infrared spectra of 1% polyarylates solutions after irradiation on chloroform and eyclohexanone, just as for the irradiation of polyarylates containing sulphur [1]. Similar absorption bands in the polyarylates being studied m a y be related to the Fries rearrangement, which takes place in the polyarylate under the action of ultraviolet radiation. As has been noted above, we also investigated the action of ultraviolet radiation on films of the polyarylates 3, 4 and 5 (Table 1). The change in the mechanical properties of the films and in the viscosity of the polyarylate solutions during TABLE 1.
P R O P E R T I E S OF HOMOGENEOUS AND M I X E D P O L Y R N Y I ~ T E S BASED ON"
PP, TC,
OCMPC A~D MPAC I
Solubility t in
J0 Starting substances (molar ratio)
0 0
0
t ~'~
0
0
o
Q~
~9
PP : MPAC
92 0.20
180
S
(I : I) PP : OCMPC (I : i)
88 0.355 320
S~
PP : TC : MPAC 80 0.37
S
S
SS
SS
S
S
S
SS
270
-
320
1330
15
S
S
S
320
1430
10
S
S
S
(1 : 0"9 : 0"1)
PP : TC : OCMPC 89 0.57 (I : 0"9 : I)
PP : TC (I : I)
90 0.65
* The temperature, corresponding to the point of intersection of the tangents to the slopes of the thermomechanical curve in the region, where the polyarylate starts to flow, was taken as the softening point. i" S - e a s i l y soluble, SS-sparingly soluble. 5 Ytscosity of the soluble part.
irradiation are shown in Fig. 2 and 3. As m a y be seen from the Figures, the film of polyarylate 4 is considerably more stable t h a n t h a t of polyarylate 5. Thus, whereas the film of polyarylate 5 loses 54~/o of its rupture strength as a result of a 10 hr irradiation at 40-2°C, the film ofpolyarylate 4 loses in all only 22~/o Fig. (3).
Photochemical degradation of polyarylates containing phosphorus
111
T h e investigation o f t h e changes in t h e physical a n d mechanical p r o p e r t i e s o f p o l y a r y l a t e s during irradiation indicates t h a t t h e i n t r o d u c t i o n o f p h o s p h o r u s into the p o l y a r y l a t e s c o n t r i b u t e s t o a n increase in its resistance t o light. This clearly t a k e s place because o f t h e scattering o f p a r t o f t h e a b s o r b e d energy. I n fact, during t h e irradiation in chloroform of p o l y a r y l a t e s containing p h o s p h o r u s in t h e chain, a n intense yellow luminescence is observed. 6,k$ /cm2
t~ -/~0~ t2 -/200 ~sp.
0.7~
~0 -~0gO
0"6
8 -~00
0"5
~5 10
5
0
T/me,hP
~~~
S - 800 O
~"o5
I
b~ . I
5
/g
T[me, hP
:FIG. 2
:FIG" 3
:FIG. 2. Change in specific viscosity during the irradiation of polyarylate films. The numbers on the curves correspond to the numbers in Table 1. FIa. 3. Change in the tensile strength (a) and elongation at rupture (8) of polyarylate fi]rna after irradiation in air. The figures on the curves correspond to the numbers of the polymers in Table 1: g, 5--tensile strength; 5'--elongation.
4",
I n conclusion t h e a u t h o r s wish t o express their t h a n k s t o V. V. R o d e for t h e c h r o m a t o g r a p h i c d e t e r m i n a t i o n o f the gaseous p r o d u c t s of d e g r a d a t i o n . TABLE
2.
MOLECULAR
C H A R A C T E R I S T I C S OF
THE
POLYARYLATES
AND DICARBOX'YLIC ACIDS COl~'TAINING PHOSPHORI)'S B E F O R E
Molecular weight Polyarylate No.
3 4 P-2
before irradiation 20,000 34,000 29,400
PP,
TEREPHTHALIC
Hydroxyl group equivalent*
after irradiation in in cyclochloroform hexanone 19,800 33,000 47,600.
OF
A N D A F T E R l~RRADIATIOl~]"
18,000 32,000 22,200
before irradiation 11,000 17,000 14,300
after irradiation in cycloin chloroform hexanone 9300 15,800 20,000
9100 15,300 10,000
* The h y d r o x y l group e q u i v a l e n t was calculated in a similar manner to t h a t described previously [1].
112
S.S. IvA~ov and L. P. GAVRYUCHENKOVA CONCLUSIONS
(1) The photochemical degradation of polyarylates containing phosphorus has been investigated in solutions of various concentrations in chloroform and in cyclohexanone, and in films. I t has been found t h a t the introduction of small quantities of phosphorus into the polyarylate increases its resistance to light. (2) Degradation of polyarylates containing phosphorus takes place in solution in cyclohexanone more rapidly than in chloroform. Translated by G. F. MODLEN REFERENCES 1. S. R. R A F I K 0 V , S. V. ~INOGRADOVA, V. V. KORSH&K, Z. Ya. F01YIINA, B. V. L O K -
SHIN and V.V. RODE, Vysokomol. soyed. 8: 2189, 1966 (Translated in Polymer Sol. U.S.S.R. 8: 12, 1966) 2. V. V. KORSHAK, I. A. GRIBOVA and M. A. ANDREYEVA, Vysokomol. soyed. 1: 825, 1959 (Not translated in Polymer Sci. U.S.S.R.) 3. V. V. KORSHAK, S. V. VINOGRADOVA and U. BAN-YUAN', Vysokomol. soyed. 5: 969, 1963 (Translated in Polymer Sci. U.S.S.R. 5: 1, 18, 1964) 4. A. M. KINNEAR and E. A. PERREN, J. Chem. Soc. 3437, 1952
CALORIMETRIC INVESTIGATION OF THE FORMATION OF A COBALT-POLY-a-ACETYLDEHYDROALANINE CHELATE* S. S. IvA~ov and L. P. GAVRYUCHE~KOVA Institute for High Molecular Weight Compounds, T.T.S.S.R,Academy of Sciences (Received 16 November 1965)
WE HAVE obtained a number of polychelates with the ions of metals of the first transitional period (Fe, Co, Ni, Cu, Zn) on the basis of poly-~-acetyldehydroalanine [1]. The process of their formation was carried out in an aqueous solution. I t is of interest to assess the heat of the formation reaction for polymer chelate complexes in aqueous solution, and also to determine their heats of formation both in aqueous solution and also in the solid state. The polychelate with CO +~ was selected as the material for the investigation. The formation of the polymer complex takes place according to the equation (CsHTOsN).~0.5 CoC12= (CsHsOsN'O'5 C0)~-t-HCI-t-AH •
(1)
To determine the heat of formation of the polychelate in aqueous solution, • Vysokomol. soyed. A9: No. 1, 103-106, 1967. • The correction for heat exchange was calculated from the Renault-Pfaundler-Usov formula [2].
107
L. K. YARALOV, Avt. svid. 171562, 1963; Byull. izobretenii, L. K. YARALOV, Vysokomol. soyed. 7: 551, 1965 (Translated 7: 3, 610, 1965) L. K. YARALOV, Vysokomol. soyed. 8: 674, 1966 (Translated 8: 4, 740, 1966) S. KOLESNIKOV, Vysokomol. soyed, 8: 870, 1966 (Translated 8: 5, 956, 1966) L. K. YARALOV, Vysokomol. soyed. 7: 1807, 1965 (Translated 7: 10, 1990, 1965)
PHOTOCHEMICAL DEGRADATION OF POLYARYLATES CONTAINING PHOSPHORUS *t S. 1~. I~AFIKOV, S. V. VII~OGRADOVA, V. V. KORSHAK a n d Z. YA. FOMIlVA Institute for Elementary Organic Compounds, U.S.S.R. Academy of Sciences
(Received 15 September 1965)
IT ~AS been shown previously [1] that the introduction of sulphur into polyarylates increases their resistance to light both in solution in chloroform and also in the form of films. With the aim of further clarifying the possibility of creating polyarylates self-resistant to light-ageing, the effect of introducing phosphorus atoms into the polyarylate structure has been investigated in the present work. In the literature there is information about phosphorus-containing polyarylates based on resorcinol, 2,2,-di-(4-hydroxyphenyl)propane(diane), hydroquinone, and such acidic components as the acid chlorides of methylphosphinic and phenylphosphinic acid [2]. The polyarylate of diane with the hydroxide of bis-(p-carboxyphenyl) methylphosphine has been described [3]. Certain polyarylates based on phenolphthalein (PP), and on the acid chlorides of methylphosphonic acid (CMPA) and of the hydroxide of bis-(p-carboxyphenyl) methylophosphine (COCMP) have been synthesized and investigated in the present work. EXPERIMENTAL Initial substances. COCMP was obtained by the method described previously, and had constants in good agreement with the literature data [3]. CMPA was purified by distillation and had a melting point of 32-33°C (melting point according to the literature data, 33°C [4]). The melting point of the PP used was 261°C. * Vysokomol. soyed. A9: :No. 1, 98-102, 1967. ~f 94th Communication in the series "Heteroehain polyesters".
108
S . R . RAFIEOV et
al.
The synthesis of the hcmogeneons and of the mixed polyarylates containing phosphorus, based on PP and CMPA, COCMP and terephthalyl Chloride (TC) was carried out by a high temperature polycondensation in a Sovol medium, at a concentration of 0.6 mole/litre, with the simultaneous introduction of all the initial components into the reaction. The temperature conditions for the polycondensation were as follows: the reaction mass was heated from 100 to 220°C in 3 hr and then held at 220°C for 14 hr. At the end of the reaction, the reaction mass was dissolved in chloroform, precipitated with methanol, the precipitated polymer was filtered off and carefully washed with methanol, hot water, twice with methanol, and dried i n v a c u o at 2-3 mmHg at 60°C for 10 hr. The homogeneous polyarylate based on PP and CMPA was obtained by polycondensation in the melt. Initially, the reaction mass was heated in a current of nitrogen for 10 hr with a gradual increase in the temperature from 10 to 200°C, and then i n v a c u o (1 mmHg) at 220°C for 1 hr and at 250°C for 2 hr. The properties of the homogeneous and of the mixed polyarylates obtained are shown in Table 1. The photochemical degradation of the polyarylates 3 and 4, shown in Table 1, was investigated in 1 and 20% solutions, and in films. Cyclohexanono and chloroform were used as solvents. The solutions were irradiated at 20 4-2°C by a mercury-quartz lamp PRK-2, with a power of 400 watts. The duration of the irradiation was 10 hr. The change in the molecular characteristics of the polyarylates during irradiation was assessed from the viscosity of dilute solutions (1% and less) in the same solvent in which the irradiation had been carried out. In many experiments, the change in the optical properties of the polyarylates during irradiation was studied: in particular, the absorption spectrum in the ultraviolet and in infrared regions was determined. The determination of the end hydroxyl groups in the irradiated and unirradiated polyarylates by Verley's method was also carried out. The molecular weights of the polyarylate~ before and after irradiation was determined by the light-scattering method. Films of the polyarylates with a thickness of 404-5 ~ were irradiated in air by means of the PRK-2 lamp at 404-2°C for 10 hr. The resistance to light of the polyarylate films was assessed from the change in their strength properties during irradiation, as determined on a Polanyi apparatus.
RESULTS AND DISCUSSION As m a y be seen f r o m the d a t a p r e s e n t e d in Table 1, the p o l y a r y l a t e b a s e d on P P a n d COCMP (polyarylate 2) has a high softening point, w h i c h is h a r d l y red u c e d a t all w h e n 0.9 mole of the p h o s p h o r u s - c o n t a i n i n g dicarboxylic acid is replaced b y t e r e p h t h a l i c acid. P o l y a r y l a t e s f r o m P P a n d CMPA are less h e a t resistant a n d in this case s u b s t i t u t i o n o f 0.9 mole m e t h y l phosphinic acid for t e r e p h t h a l a t e causes a conside r a b l y increase in t h e softening t e m p e r a t u r e of the m i x e d polymer. P o l y a r y l a r e s 1, 3 a n d 4 are easily soluble in m a n y organic solvents, chloroform, eyclohexanone, c a r b o n tetrachloride, etc. The h o m o p o l y a r y l a t e 2 (based o n t h e arom a t i c p h o s p h o r u s - c o n t a i n i n g acid) is sparingly soluble in these solvents. T h e polya r y l a t e s 1 a n d 2, containing 8.20 a n d 5.35% p h o s p h o r u s , b u r n w i t h difficulty a n d are self-extinguishing w h e n t h e flame is r e m o v e d . F i g u r e 1 shows the change in the viscosity of solutions of the m i x e d p h o s p h o r u s containing p o l y a r y l a t e s a n d of the p o l y a r y l a t e P - 2 ( P P a n d terephthalie acid) d u r i n g their irradiation in 1 a n d 20% solutions in chloroform a n d cyclohexanone. I t is clear f r o m this Figure, t h a t w h e n 1% solutions of t h e p h o s p h o r u s - c o n t a i n i n g p o l y a r y l a t e s in chloroform are irradiatied, their viscosity falls only slightly (Fig.
Photochemical degradation of polyarylates containing phosphorus
109
la, curves 3, 4), whereas the viscosity of the solutions of polyarylate P-2 falls from 0.65 to 0-19 t h a t is, by 70% (Fig. la, curve 5). Different behaviour is observed when 1% solutions of the polyarylates in cyclohexanone are irradiated. As m a y be seen from Fig. la (curves 3', 6', 5'), b
~sp
oj
f
a 0.6
o
o~, ~r
o
o3r
0.*
0"2 0
Z~' 0.2 $
T/me,hi,
/0
~ne, hp
FIG. 1. Change in the specific viscosity during irradiation of (a) 1%, and (b) 20%, solutions of polyarylates in chloroform and cyclohexanone. The numbers on the curves correspond to the numbers of the polymers in Table 1: 3, 4, 5--irradiated in chloroform; 3', g', 5'--irradiated in cyclohexanone. the viscosity of polyarylate solutions markedly falls, especially during the initial period of irradiation, but after about 5 hr, it remains practically unchanged. Data obtained during the irradiation of 20 ~/5 solutions of the polyarylates in chloroform and in cyclohexanone are shown in Fig. lb. I t m a y be seen from them t h a t no reduction in the viscosity of the solutions is observed during irradiation of polyarylates 3 and 4 in chloroform. The molecular weight of the polymer and the hydroxyl group equivalent thus remain practically unchanged (Table 2). When polyarylate P-2 is irradiated under similar conditions an increase in the molecular weight of 40% is observed (although the specific viscosities of the solutions thus undergo a scarcely significant increase). I t m a y be concluded from the data presented that no crossli~king of the polyarylate chains takes place during the irradiation of concentrated solutions of the polyarylates 3 and 4 in chloroform or in cyclohexanone. CO and CO 2 were observed in the gaseous products of the degradation of polyarylates 3 and 4 in solution, as had been the case during the light-ageiag of solutions of polyarylates P-2 and of polyarylates containing sulphur [1]. This forms a basis for proposing t h a t the general course of degradation in solutions, and also in the condensed phase, evidently consists in the rupture of an ester bond, predominantly of the lactone ring, with the formation of free radicals, secondary reactions of the free radicals leading to the release of CO and COm. However, as distinct from the process of light ageing in films, in ~solutions the recombination of radicals and the formation of branched and crosslinked structures is difficult. In cyclohexanone, as in cases previously investigated, there
S. R. R~r~ov et aL
II0
evidently takes place a reaction between the aroxyl radicals formed and the solvent, and this leads to a certain increase in the hydroxyl group concentration and even to free phenols to the mechanism: --Re. +RH->--ROH-t-R. Absorptions bands in the 1630-1640 cm -1 region were observed in the infrared spectra of 1% polyarylates solutions after irradiation on chloroform and eyclohexanone, just as for the irradiation of polyarylates containing sulphur [1]. Similar absorption bands in the polyarylates being studied m a y be related to the Fries rearrangement, which takes place in the polyarylate under the action of ultraviolet radiation. As has been noted above, we also investigated the action of ultraviolet radiation on films of the polyarylates 3, 4 and 5 (Table 1). The change in the mechanical properties of the films and in the viscosity of the polyarylate solutions during TABLE 1.
P R O P E R T I E S OF HOMOGENEOUS AND M I X E D P O L Y R N Y I ~ T E S BASED ON"
PP, TC,
OCMPC A~D MPAC I
Solubility t in
J0 Starting substances (molar ratio)
0 0
0
t ~'~
0
0
o
Q~
~9
PP : MPAC
92 0.20
180
S
(I : I) PP : OCMPC (I : i)
88 0.355 320
S~
PP : TC : MPAC 80 0.37
S
S
SS
SS
S
S
S
SS
270
-
320
1330
15
S
S
S
320
1430
10
S
S
S
(1 : 0"9 : 0"1)
PP : TC : OCMPC 89 0.57 (I : 0"9 : I)
PP : TC (I : I)
90 0.65
* The temperature, corresponding to the point of intersection of the tangents to the slopes of the thermomechanical curve in the region, where the polyarylate starts to flow, was taken as the softening point. i" S - e a s i l y soluble, SS-sparingly soluble. 5 Ytscosity of the soluble part.
irradiation are shown in Fig. 2 and 3. As m a y be seen from the Figures, the film of polyarylate 4 is considerably more stable t h a n t h a t of polyarylate 5. Thus, whereas the film of polyarylate 5 loses 54~/o of its rupture strength as a result of a 10 hr irradiation at 40-2°C, the film ofpolyarylate 4 loses in all only 22~/o Fig. (3).
Photochemical degradation of polyarylates containing phosphorus
111
T h e investigation o f t h e changes in t h e physical a n d mechanical p r o p e r t i e s o f p o l y a r y l a t e s during irradiation indicates t h a t t h e i n t r o d u c t i o n o f p h o s p h o r u s into the p o l y a r y l a t e s c o n t r i b u t e s t o a n increase in its resistance t o light. This clearly t a k e s place because o f t h e scattering o f p a r t o f t h e a b s o r b e d energy. I n fact, during t h e irradiation in chloroform of p o l y a r y l a t e s containing p h o s p h o r u s in t h e chain, a n intense yellow luminescence is observed. 6,k$ /cm2
t~ -/~0~ t2 -/200 ~sp.
0.7~
~0 -~0gO
0"6
8 -~00
0"5
~5 10
5
0
T/me,hP
~~~
S - 800 O
~"o5
I
b~ . I
5
/g
T[me, hP
:FIG. 2
:FIG" 3
:FIG. 2. Change in specific viscosity during the irradiation of polyarylate films. The numbers on the curves correspond to the numbers in Table 1. FIa. 3. Change in the tensile strength (a) and elongation at rupture (8) of polyarylate fi]rna after irradiation in air. The figures on the curves correspond to the numbers of the polymers in Table 1: g, 5--tensile strength; 5'--elongation.
4",
I n conclusion t h e a u t h o r s wish t o express their t h a n k s t o V. V. R o d e for t h e c h r o m a t o g r a p h i c d e t e r m i n a t i o n o f the gaseous p r o d u c t s of d e g r a d a t i o n . TABLE
2.
MOLECULAR
C H A R A C T E R I S T I C S OF
THE
POLYARYLATES
AND DICARBOX'YLIC ACIDS COl~'TAINING PHOSPHORI)'S B E F O R E
Molecular weight Polyarylate No.
3 4 P-2
before irradiation 20,000 34,000 29,400
PP,
TEREPHTHALIC
Hydroxyl group equivalent*
after irradiation in in cyclochloroform hexanone 19,800 33,000 47,600.
OF
A N D A F T E R l~RRADIATIOl~]"
18,000 32,000 22,200
before irradiation 11,000 17,000 14,300
after irradiation in cycloin chloroform hexanone 9300 15,800 20,000
9100 15,300 10,000
* The h y d r o x y l group e q u i v a l e n t was calculated in a similar manner to t h a t described previously [1].
112
S.S. IvA~ov and L. P. GAVRYUCHENKOVA CONCLUSIONS
(1) The photochemical degradation of polyarylates containing phosphorus has been investigated in solutions of various concentrations in chloroform and in cyclohexanone, and in films. I t has been found t h a t the introduction of small quantities of phosphorus into the polyarylate increases its resistance to light. (2) Degradation of polyarylates containing phosphorus takes place in solution in cyclohexanone more rapidly than in chloroform. Translated by G. F. MODLEN REFERENCES 1. S. R. R A F I K 0 V , S. V. ~INOGRADOVA, V. V. KORSH&K, Z. Ya. F01YIINA, B. V. L O K -
SHIN and V.V. RODE, Vysokomol. soyed. 8: 2189, 1966 (Translated in Polymer Sol. U.S.S.R. 8: 12, 1966) 2. V. V. KORSHAK, I. A. GRIBOVA and M. A. ANDREYEVA, Vysokomol. soyed. 1: 825, 1959 (Not translated in Polymer Sci. U.S.S.R.) 3. V. V. KORSHAK, S. V. VINOGRADOVA and U. BAN-YUAN', Vysokomol. soyed. 5: 969, 1963 (Translated in Polymer Sci. U.S.S.R. 5: 1, 18, 1964) 4. A. M. KINNEAR and E. A. PERREN, J. Chem. Soc. 3437, 1952
CALORIMETRIC INVESTIGATION OF THE FORMATION OF A COBALT-POLY-a-ACETYLDEHYDROALANINE CHELATE* S. S. IvA~ov and L. P. GAVRYUCHE~KOVA Institute for High Molecular Weight Compounds, T.T.S.S.R,Academy of Sciences (Received 16 November 1965)
WE HAVE obtained a number of polychelates with the ions of metals of the first transitional period (Fe, Co, Ni, Cu, Zn) on the basis of poly-~-acetyldehydroalanine [1]. The process of their formation was carried out in an aqueous solution. I t is of interest to assess the heat of the formation reaction for polymer chelate complexes in aqueous solution, and also to determine their heats of formation both in aqueous solution and also in the solid state. The polychelate with CO +~ was selected as the material for the investigation. The formation of the polymer complex takes place according to the equation (CsHTOsN).~0.5 CoC12= (CsHsOsN'O'5 C0)~-t-HCI-t-AH •
(1)
To determine the heat of formation of the polychelate in aqueous solution, • Vysokomol. soyed. A9: No. 1, 103-106, 1967. • The correction for heat exchange was calculated from the Renault-Pfaundler-Usov formula [2].