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Determination of the crystallinity of methyl methacrylate-phenyldichlorophosphine copolymers
DETERMINATION OF THE CRYSTALLINITY OF METHYL METHACRYLATE-PHENYLDICHLOROPHOSPHINE COPOLYMERS* B. LASZKIEWICZ
and A.
WLOCHOWICZ
L6d£ P o l y t e c h n i c I n s t i t u t e , P o l a n d
(Received 19 Febr~ary 1964) ORGANOPHOSPHOROUS polymers have recently attracted the attention of a number of chemists [1-5]. This is because of their physicochemieal properties, particularly their high resistance to various chemical media, their noninflaminability [6], transparency [7, 8] and thermal stability. The object of our researches was the eopolymer of methyl methaerylate (MMA) with phenyldiehlorophosphine (PDCP):
//--C--CH~--/
--P--
l\
CsHs
,~
Copolymerization of MMA with P D C P was carried out in the presence of azobisisobutyronitrile [9] using the bulk method at 60 ° for 10 hours. The copolymer was purified b y precipitation b y petroleum ether from solution in chloroform. In studying the process of copolymerization particular attention was paid to the fact that the molecular weight of the eopolymer at first rises to a maximum and then falls markedly. TABLE 1. CHARACTERISTICS OF SPEC,IMENS
Specimen, No.
l
2 3 4 5
Molar r a t i o MMA : P D C P
1 : 0"00 1 : 0'08 1 : 0-12
1 : 0"28 1:0'34
Phosphorus content of c o p o l y m e r , o/ /O
0"0 2"5 3'9 8'8 10"8
* V y s o k o m o l . soyed. 6::No. 9, 1722-1724, 1964. 1907
i M.p., °C
, ! temperature I . ot copolymers, °C
215-227 214-223 216-220 203-208 168-175
308 294 280 287 247
B. LASZKIEWICZ and A. WLOCHOWICZ
1908
The solubility of the organophosphorous copolymers produced in acetone and chloroform depends on the time of eopolymerizatioll and the phosphorus content of the copolymer, usually falling as this rises. To find out the variations in the properties of the copolymers formed during copolymerization of MMA with PDCP, the crystallinity of the products was studied as dependent on the phosphorus content of the macromolecule. Table 1 sets out the physicochemical properties and phosphorus concentration of the specimens studied. EXPERIMENTAL The crystallinity index was d e t e r m i n e d b y t h e H e r m a n s - W e i d i n g e r m e t h o d [10, 11]. X - r a y diffraction p a t t e r n s were recorded b y a Goppel micro c a m e r a [12] using a p o l y e t h y l e n e film as t h e standard, and C u K a radiation. The exposure t i m e was 5½ hours w i t h 30 k v and anode current of 17 MA. The specimen was 1.2 m m in diam, and t h e collimator was also 1.2 m m in diam. The distance b e t w e e n t h e n e g a t i v e and specimen was 82 m m . Three photographs were m a d e for each specimen (see Fig.). T h e y were p h o t o m e t r e d radially on a Zeiss M-2 m i c r o p h o t o m e t e r w i t h graduations of 0.1 ram. T h e darkening of the n e g a t i v e (D) was p l o t t e d f r o m the results as a function of the dist a n c e f r o m the centre of t h e diffraction p a t t e r n , r(O). The b a c k g r o u n d of the n e g a t i v e was s e p a r a t e d f r o m t h e X - r a y dispersion b y atmospheric molecules and the incoherent r a d i a t i o n b y t h e t a n g e n t to t h e m i n i m u m on the graph. The c r y s t a l l i n i t y index, K , was d e t e r m i n e d from: Y K ~ - - .10 s, Rp where F is the surface u n d e r t h e darkening c u r v e of the negative, Rp is the m a x i m u m darkening of t h e c o m p a r i s o n reflection (polyethylene film).
DISCUSSION It is evident from the diffraction patterns (see Fig.) and the figures shown in Table 2, that the organophosphorus copolymers studied have low molecular TABLE 2. CRYSTALLINITY INDICES
Specimen No.
Specimen
Homopolymer MMA Copolymer w i t h
2-5% Ditto
3.9%
,,
8.8%
,,
10.8%
Mean value of surface of reflex studied
Mean darkening of relative reflection
Crystallinity index
353'3
73'2
482.8
335'0 344'3 206'3 174"3
56'6 72'0 71"8 58"1
591.9 478.2 287"3 300.0
The erystallinity of MMA with I'DCI'
1909
Diffract, ion patterns of the copolymers studied: / - - t h e homopolymer MMA; 2 - - e o p o l y m e r containing 2.5(}~) phosphorus; 3--ditto 3.9o~'); 4--ditto 8.8°o; ,i--(titt.o 10.8°~,.
1910
B. LASZKIEWICZ
and A. WLOCHOWICZ
ordering. I t is confirmed t h a t K of these p o l y m e r s falls as the p h o s p h o r u s c o n t e n t of t h e maeromoleeules rises; this is iu good a g r e e m e n t w i t h the findings shown in Table 1. T h e r e l a t i v e l y low crystallinity indices are due to t h e lack o f s y m m e t r y in t h e s t r u c t u r e o f t h e o r g a n o p h o s p h o r u s c o p o l y m e r m a c r o m o l e c u l a r chains. Besides h a v i n g no geometrical s y m m e t r y , due to t h e changed structure, these copolymers also lack r e p e t i t i o n s y m m e t r y , due to the different reactive c a p a c i t y of MMA a n d P D C P , r 1 ~ 6 . 7 a n d r2----0.1 r e s p e c t i v e l y [9]. Due to this big difference in the r e a c t i v i t y of the m o n o m e r s their relative c o n c e n t r a t i o n varies during the reaction, which m e a n s t h a t in the l a t t e r stages of the c o p o l y m e r i z a t i o n process t h e r e is a big increase in the P D C P concentration. P D C P can " c a p t u r e " the free radicals, for which reason t h e r e is a n increase in its c o n c e n t r a t i o n in the reaction m i x t u r e a n d this leads to t h e f o r m a t i o n o f macromolecules with low p o l y m e r i zation coefficients. This k i n d o f m a c r o m c l e c u l e does n o t f o r m large o r d e r e d groups, a n d t h e r e f o r e its crystallinity i n d e x c a n n o t be high. CONCLUSIONS
(1) T h e c r y s t a l l i n i t y i n d e x of copolymers of m e t h y l m e t h a c r y l a t e a n d p h e n y l dichlorophosphine is low. (2) T h e c r y s t a l l i n i t y i n d e x falls as the p h o s p h o r u s c o n t e n t o f the macromolecule rises. Translated by V. ALFOttD REFERENCES
1. F. PATET and P. DERST, Angew. Chem. 71: 105, 1959 2. E. L. GEFTER, Fosfororgan. monomery i polimery. (Organophosphorus Monomers and Polymers.) Izd. Akad. /qauk. SSSR, Moscow, 1960 3. C. It. BAMFORD et al., The Kinetics of Vinyl Polymerization by Radical Mechanisms, Butterworth Scientific Publications, London, 1958 4. J. PELLON, J. Polymer Sci. 43: 577, 1960 5. Ao D. F. TOY, Mod. Plast. 24: 226, 1947 6. A. BORYNIEC and B. I~ASZKIEWICZ, Roczn. Chem. 36: 362, 1962 7. A. D. T. TOY and R. S. COOPER, J. Amer. Chem. Soc. 76: 2191, 1954 8. J. KENNEDY, J. Amer. Chem. Soc. 80: 465, 1958 9. B. LASZKIEWICZ, Dissertation, LSdl Polytechnic Inst., LSdi, 1964 10. P. H. HERMANS and A. WEIDINGER, J. Appl. Phys. 19: 491, 1948 11. P. H. HERMANS and A. WEIDINGER, Kolloid-Z. 115: 103, 1949 12. J. M. GOPPEL, Appl. Sci. Res. 1: 18, 1947
and A.
WLOCHOWICZ
L6d£ P o l y t e c h n i c I n s t i t u t e , P o l a n d
(Received 19 Febr~ary 1964) ORGANOPHOSPHOROUS polymers have recently attracted the attention of a number of chemists [1-5]. This is because of their physicochemieal properties, particularly their high resistance to various chemical media, their noninflaminability [6], transparency [7, 8] and thermal stability. The object of our researches was the eopolymer of methyl methaerylate (MMA) with phenyldiehlorophosphine (PDCP):
//--C--CH~--/
--P--
l\
CsHs
,~
Copolymerization of MMA with P D C P was carried out in the presence of azobisisobutyronitrile [9] using the bulk method at 60 ° for 10 hours. The copolymer was purified b y precipitation b y petroleum ether from solution in chloroform. In studying the process of copolymerization particular attention was paid to the fact that the molecular weight of the eopolymer at first rises to a maximum and then falls markedly. TABLE 1. CHARACTERISTICS OF SPEC,IMENS
Specimen, No.
l
2 3 4 5
Molar r a t i o MMA : P D C P
1 : 0"00 1 : 0'08 1 : 0-12
1 : 0"28 1:0'34
Phosphorus content of c o p o l y m e r , o/ /O
0"0 2"5 3'9 8'8 10"8
* V y s o k o m o l . soyed. 6::No. 9, 1722-1724, 1964. 1907
i M.p., °C
, ! temperature I . ot copolymers, °C
215-227 214-223 216-220 203-208 168-175
308 294 280 287 247
B. LASZKIEWICZ and A. WLOCHOWICZ
1908
The solubility of the organophosphorous copolymers produced in acetone and chloroform depends on the time of eopolymerizatioll and the phosphorus content of the copolymer, usually falling as this rises. To find out the variations in the properties of the copolymers formed during copolymerization of MMA with PDCP, the crystallinity of the products was studied as dependent on the phosphorus content of the macromolecule. Table 1 sets out the physicochemical properties and phosphorus concentration of the specimens studied. EXPERIMENTAL The crystallinity index was d e t e r m i n e d b y t h e H e r m a n s - W e i d i n g e r m e t h o d [10, 11]. X - r a y diffraction p a t t e r n s were recorded b y a Goppel micro c a m e r a [12] using a p o l y e t h y l e n e film as t h e standard, and C u K a radiation. The exposure t i m e was 5½ hours w i t h 30 k v and anode current of 17 MA. The specimen was 1.2 m m in diam, and t h e collimator was also 1.2 m m in diam. The distance b e t w e e n t h e n e g a t i v e and specimen was 82 m m . Three photographs were m a d e for each specimen (see Fig.). T h e y were p h o t o m e t r e d radially on a Zeiss M-2 m i c r o p h o t o m e t e r w i t h graduations of 0.1 ram. T h e darkening of the n e g a t i v e (D) was p l o t t e d f r o m the results as a function of the dist a n c e f r o m the centre of t h e diffraction p a t t e r n , r(O). The b a c k g r o u n d of the n e g a t i v e was s e p a r a t e d f r o m t h e X - r a y dispersion b y atmospheric molecules and the incoherent r a d i a t i o n b y t h e t a n g e n t to t h e m i n i m u m on the graph. The c r y s t a l l i n i t y index, K , was d e t e r m i n e d from: Y K ~ - - .10 s, Rp where F is the surface u n d e r t h e darkening c u r v e of the negative, Rp is the m a x i m u m darkening of t h e c o m p a r i s o n reflection (polyethylene film).
DISCUSSION It is evident from the diffraction patterns (see Fig.) and the figures shown in Table 2, that the organophosphorus copolymers studied have low molecular TABLE 2. CRYSTALLINITY INDICES
Specimen No.
Specimen
Homopolymer MMA Copolymer w i t h
2-5% Ditto
3.9%
,,
8.8%
,,
10.8%
Mean value of surface of reflex studied
Mean darkening of relative reflection
Crystallinity index
353'3
73'2
482.8
335'0 344'3 206'3 174"3
56'6 72'0 71"8 58"1
591.9 478.2 287"3 300.0
The erystallinity of MMA with I'DCI'
1909
Diffract, ion patterns of the copolymers studied: / - - t h e homopolymer MMA; 2 - - e o p o l y m e r containing 2.5(}~) phosphorus; 3--ditto 3.9o~'); 4--ditto 8.8°o; ,i--(titt.o 10.8°~,.
1910
B. LASZKIEWICZ
and A. WLOCHOWICZ
ordering. I t is confirmed t h a t K of these p o l y m e r s falls as the p h o s p h o r u s c o n t e n t of t h e maeromoleeules rises; this is iu good a g r e e m e n t w i t h the findings shown in Table 1. T h e r e l a t i v e l y low crystallinity indices are due to t h e lack o f s y m m e t r y in t h e s t r u c t u r e o f t h e o r g a n o p h o s p h o r u s c o p o l y m e r m a c r o m o l e c u l a r chains. Besides h a v i n g no geometrical s y m m e t r y , due to t h e changed structure, these copolymers also lack r e p e t i t i o n s y m m e t r y , due to the different reactive c a p a c i t y of MMA a n d P D C P , r 1 ~ 6 . 7 a n d r2----0.1 r e s p e c t i v e l y [9]. Due to this big difference in the r e a c t i v i t y of the m o n o m e r s their relative c o n c e n t r a t i o n varies during the reaction, which m e a n s t h a t in the l a t t e r stages of the c o p o l y m e r i z a t i o n process t h e r e is a big increase in the P D C P concentration. P D C P can " c a p t u r e " the free radicals, for which reason t h e r e is a n increase in its c o n c e n t r a t i o n in the reaction m i x t u r e a n d this leads to t h e f o r m a t i o n o f macromolecules with low p o l y m e r i zation coefficients. This k i n d o f m a c r o m c l e c u l e does n o t f o r m large o r d e r e d groups, a n d t h e r e f o r e its crystallinity i n d e x c a n n o t be high. CONCLUSIONS
(1) T h e c r y s t a l l i n i t y i n d e x of copolymers of m e t h y l m e t h a c r y l a t e a n d p h e n y l dichlorophosphine is low. (2) T h e c r y s t a l l i n i t y i n d e x falls as the p h o s p h o r u s c o n t e n t o f the macromolecule rises. Translated by V. ALFOttD REFERENCES
1. F. PATET and P. DERST, Angew. Chem. 71: 105, 1959 2. E. L. GEFTER, Fosfororgan. monomery i polimery. (Organophosphorus Monomers and Polymers.) Izd. Akad. /qauk. SSSR, Moscow, 1960 3. C. It. BAMFORD et al., The Kinetics of Vinyl Polymerization by Radical Mechanisms, Butterworth Scientific Publications, London, 1958 4. J. PELLON, J. Polymer Sci. 43: 577, 1960 5. Ao D. F. TOY, Mod. Plast. 24: 226, 1947 6. A. BORYNIEC and B. I~ASZKIEWICZ, Roczn. Chem. 36: 362, 1962 7. A. D. T. TOY and R. S. COOPER, J. Amer. Chem. Soc. 76: 2191, 1954 8. J. KENNEDY, J. Amer. Chem. Soc. 80: 465, 1958 9. B. LASZKIEWICZ, Dissertation, LSdl Polytechnic Inst., LSdi, 1964 10. P. H. HERMANS and A. WEIDINGER, J. Appl. Phys. 19: 491, 1948 11. P. H. HERMANS and A. WEIDINGER, Kolloid-Z. 115: 103, 1949 12. J. M. GOPPEL, Appl. Sci. Res. 1: 18, 1947