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Preparation of graft copolymers—V. Grafting of vinyl monomers on polyethylene terephthalate (Lavsan)
PREPARATION OF GRAFT COPOLYMERS--V. GRAFTING OF VINYL MONOMERS ON POLYETHYLENE TEREPHTHALATE (LAVSAN)* V.V. KORSHAK, K. K. MOZGOVA and M. A. SHKOLINA Institute of Organo.elemental Compounds, U.S.S.R. Academy of Sciences
(Received 18 June 1959) IN the present investigation the conditions for the synthesis of graft copolymers, from industrial materials was studied, using ozone as an activator for the polymerization. As the subject of our study we used a polyester--polyethylene terephthalate ("lavsan"), used in the form of thin films and fibres. As with polyamides, the initial samples of polyesters were treated with ozone and then heated in a stream of nitrogen, with styrene, acrylonitrile, vinylyd e n e chloride and vinyl acetate. The method used has been described previously [1-3]. DISCUSSION OF RESULTS
The investigation showed a distinct possibility of applying the given method of grafting not only to the series of polyamides, but also to a series of polyesters. I t was found that styrene easily grafts on to the polymer giving a graft eopolymer with a conversion of up to 60 per cent. Moreover, films and fibres of lavsan, even without activation with ozone, react with styrene giving a graft eopolymer but with a lower conversion. A similar phenomenon, was observed earlier with a series of polyamides when samples reacted with vinyl monomers without being ozonised [3]. As we have shown in the study of polyamides, this reaction takes place with samples of industrial products in which active centres occur. The formation of the latter is caused by various factors--destructive oxidation, presence of impurities, ete--as a result of which peroxide and hydroperoxide groups are formed in the polymer. Table 1 shows the change in weight of sample films of lavsan after copolymerization with styrene; Table 2 - - t h e same data shown for fibre samples of "lavsan". Examination of these Tables shows that the yield of graft copolymers varies little with different samples of films. * Vysokomol. soedin. 1: No. 11, 1604-1609, 1959. 70
Grafting of vinyl monomers on polyethylene terephthalate
TABLE 2. GRAFTING OF STYRENE ON TO LAYSAN FIBRES (5 IIR AT 80cC IN A STREAM OF NITROGEN)
TABLE 1. GRAFTING OF STYRENE ON TO LAVSAN FILMS (5 HR AT 80°C IN A STREAM OF NITROGEN)
Ozonization Time (rain)
Increase in weight (%)
0 5 10 6o
1.04 0.78
71
Ozonization
I n c r e a s e in weight after
. . . . . . . .
]
Time (rain)
grafting (0/0) 46"79 43"76 52"61 52"84
I n c r e a s e in
weight (°o)
0 5 10
-
[ncrease in weight after grafting (q~,) 17'01
-
0-39 0"25
23"38 39"81
C o m p a r i n g these results with the d a t a found for the fibres, it can be seen t h a t for t h e l a t t e r the yield of the c o p o l y m e r is lower t h a n t h a t for the films. These facts agree with the observations m a d e b y us on a series of polyamides, a n d t h e y are a p p a r e n t l y explained b y the different degree of o r i e n t a t i o n of films and fibres a n d t h e r e s u l t a n t o p p o r t u n i t y for the materials to absorb the monomer. W e suggest t h a t the i n t e r a c t i o n of the ozonised polyester with the vinyl m o n o m e r occurs as the result of the f o r m a t i o n of a h y d r o p e r o x i d e , w h i c h decomposes to give a free radical, which t h e n initiates the polymerization. W e t h i n k t h a t the graft p o l y m e r based oll lavsan and s t y r e n e is formed by the following mechanism: ....
OCH2CH~OOCCeH4CO--...-~ ()~ ~ . . .
--OCH 2--CH--()OC--C6 H~--CO-- . . . ---,
I
t --4 . .. OCH,CHOOCC6H4CO-- . . . CH~:- CHR ]
O"
~ . .
OOH . --()CH~CH OOC(~sH4CO-- . . . ---, I ()CH~--CH--
J
R
I t is obvious t h a t this process of f o r m a t i o n of a graft polylner m a y not de* velop in such a simple way as t h a t indicated b y the a b o v e mechaifism. I t is possible t h a t o t h e r parallel reactions occur simultaneously. I n Table 3 are given the changes f o u n d on testing the mechanical properties of the original films of lavsan and films a f t e r grafting on of styrene. Analysis of the above d a t a leads us to the conclusion t h a t if the sample of polyester is ozonised for a short time (5 min) t h e n its elongation increases as a result of c o p o l y m e r i z a t i o n with styrene, although its stability towards breaking decreases. T h e c o p o l y m e r o b t a i n e d from prolonged ozonisation of the sample, becomes more brittle (elongation decreases), possibly on account of the g r o w t h of a layer o f p o l y s t y r e n e , and the resistance to breaking increases slightly (apparently, as a result of linking of the p o l y m e r chains u n d e r the influence o f ozone).
T2
V.V. KORSHAKet al. TABLE 3. CHANGEIN MECHANICALPROPERTIES OF FILM AND FIBRE SAMPLES OF LAVSAN, AFTER OZONIZATION AND GRAFTING ON OF STYRENES FO/TII
of mate rial
Original sample %
kg/em z
Film Film Fibre
192.7 192.7 16.6
1552 1552 5852
The same sample after Time of ozonization and grafting ozonization of styrene (min) % I kg/em2 5 300 5
280 192.1 31
876.4 1115.0 4018
M e a s u r e m e n t of the film thickness o f the samples before a n d a f t e r grafting showed t h a t it increased from 19-20/~ for the initial samples to 32-38/~ for the final samples. D u r i n g t h e s t u d y o f the t h e r m o - c h e m i c a l properties o f lavsan it was f o u n d t h a t , a f t e r the grafting on o f styrene, it began to melt at a higher t e m p e r a t u r e , a l t h o u g h this increase is not so m a r k e d as in the case of amide G-669 and s t y r e n e (Fig. 1). T h e d a t a in Table 4 show t h a t with an increase in the time of ozonization t h e viscosity o f lavsan solution g r a d u a l l y increased, which is explained b y the
~,~'o 100 ~-
Y
50
gO 30 ¢0 50
100
/ 5 ~ T e m p e r a t u r(°C) e~
J
gO0
~
FIG. 1. Thermo-mechanical curves of samples of lavsan films. (1) Initial sample; (2) After treatment with styrene, cross-linking of chains u n d e r the influence of ozone. After the t r e a t m e n t of t h e ozonised sample w i t h s t y r e n e t h e specific viscosity of its solutions b e c a m e even higher, a p p a r e n t l y as the result of f o r m a t i o n of new chains, p r o b a b l y m u c h longer, p a r t i a l l y b r a n c h e d and even cross-linked.
.73
Grafting of vinyl monomers on polyethylene terephthalato
TABLE 4. CHANGE IN VISCOSITYOF 0"50/0 SOLUTIONOF SAMPLEIN CRESOL AFTER OZONIZING AND GRAFTING ON OF STYRENE (5 HR AT 80~C IN A STREAM OF NITROGEN) Time ofozonizing: 5 rain rhp before tl~p after copoly- - - .~ • .. / merization with- II " after ! tlsp alter o z o n l z f l ~ [ IOYI I out ozonizing I ozonizing eopo~ymerl, !, I zation qsp
0.248* 0-272t
]
I ,
- -
0-705
"
•
0"273 --
0"464 0.742
•
Times of ozonizing: 5 hr ...... , ............. q~p after i tlsp after ozonizing iI copolymerization i! i
0-305 --
0.610 --
• viscosity measured in 1957; solvcnt-m--cresol, t Viscositymeasured in 1959; solvent tri-crcsol.
Grafting of polystyrene on to samples of lavsan which occurred with a noticeable absorption, was found to change the elementary structure of the original polyester. T a b l e 5 s h o w s t h e c h a n g e in t h e e l e m e n t a r y s t r u c t u r e o f t h e g r a f t e d s a m p l e s compared with the original: after grafting of styrene a noticeable increase of t h e c a r b o n c o n t e n t ( u p t o 10 p e r c e n t ) a n d h y d r o g e n c o n t e n t is o b s e r v e d in t h e samples. Growth of a surface layer of polystyrene on the polyester not surprisingly altered the ease with which the grafted polymers are wetted by various solvents. A n o t i c e a b l e d e c r e a s e in w e t t i n g o f t h e s a m p l e s b y s o l v e n t s s u c h a s b e n z e n e , chloroform and dioxane was discovered. TABLE 5. CHANGE IN '[tie ELEMENTAL ANALYSISOF FILM AND FIBRES OF LAVSAN BEFORE AND AFTER OZONIZING AND TREATMENT WITH STYRENE F o r m of material
Fibre Fibre Fihn
Composition of original sample (%) C
H
62-13 61'95 61"95
4"18 4"19 4-19
62.52 62.53
4.30 4.48
Time of ozonizing I (rain) 5 l0 60
Composition of grafting Copolymer ( ° / o )
!---C-i---H 68.29 68.30 71.47 71.72 73" 11 72-87
Calculated for (CIoHsO4) (%)
.... l - - c 5.01 4-99 5.40 5.43 5.45 5.47
...... i - - H - - - -
62.50
4.19
T h e s t u d y o f t h e o p t i c a l p r o p e r t i e s o f film s a m p l e s s h o w e d t h a t t h e i n f r a - r e d s p e c t r a o f g r a f t p o l y m e r s differ f r o m t h e s p e c t r a o f t h e o r i g i n a l s a m p l e s b y c h a n g e s i n t h e r e g i o n o f 705 a n d 765 c m -1. A p p e a r a n c e o f n e w a b s o r p t i o n m a x i m a a t t h e s e w a v e l e n g t h s is e v i d e n c e that the polyester acquires frequencies which are characteristic of the monos u b s t i t u t e d b e n z e n e d e r i v a t i v e s . F r o m t h e d a t a o f B e l l a m y [4], t h e s e f r e q u e n c i e s
74
V.V. KOI~SHAKet aL
represent the non-planar deformation vibrations of the C - - H bonds. The I.R. absorption spectra are shown on Fig. 2a, b and e. Study of the same samples in the U.V. region of spectrum shows a certain difference caused by the grafting of polystyrene; the absorption curve for ]avsan
t
.)
J j.-.~
76C
,/
780 800
\ f
7 \
8tO
)
s"
('
i"
g2g
r"-
5"
960 r."
,
)
7 ~"
z..~i
~.'f
~
j f.-
-
3
C
~
o zc,ogo80100
Absorption % a
g 20 c g # o s o l g o
Absorption% b
60 60 80 100
Absorption % c
FIG. 2. Infra,red absorption spectra. (a) Initial sample of lavsan film; (b) The same sample after treatment with styrene, without ozonisation; (c) After treatment with styrene with preliminary ozonisatiorl for 10 min.
is however very indistinct and therefore these changes are illsufficiently characteristic. Changes in U.V. absorption of the samples is shown in Fig. 3a and 3b. The ease of grafting of other monomers on to ozonised samples of lavsan was studied for the fibres of this polyester and such monomers as vinyl acetate
Grafting of vinyl monomers on polyethylene terephthalate
75
a n d vinylidene chloride. I t was f o u n d t h a t b o t h m o n o m e r s g r a f t on to the fibres v e r y weakly; this is in a g r e e m e n t w i t h our observations on t h e i n t e r a c t i o n o f
T .... ~_ -
xg
I ,I I I
•
I
tl
inIT[[IIl
I I
-c9 t11tll
t
oz
-
o.!
3b ~,raa!xd3 0)' ~ "
Z5
' 'Z'5'
a
Sg~.oY~.lg3
5
FIG. 3. Ultra-violet absorption spectrum. (a) Initial sample of lavsan fihn; (b) The saxne sample after treatment with styrene: (1) without ozonising; (2) sample previously ozonised for 10 rain. TABLE 6. TREATI~IENT OF LAVSAN FIBRES WITH V1NYLIDENE CHLORIDE (5HR AT 30°C IN A STREA~I OF N2)
Ozonization
TABLE 7. TREATMENT OF LAVSANFIBRE WITH VINYL ACETATE (5HR AT 75°C IN A STREAM OF N2)
Ozonization
Increase in
Time (rain)
I n c r e a s e in w e i g h t (%)
weight after g r a f t i n g (%)
0 5 300
-()'39 2.09
1-78 0.93 None
Time (rain)
Increase in
I n c r e a s e in w e i g h t (%)
weight after grafting(%)
0 5 30
-0.18 --
1"94 1.31 3'00
300
2.05
None
these m o n o m e r s with p o l y a m i d e s [31. The e x p e r i m e n t a l results obtained are given in Tables 6 and 7. On s t u d y i n g the same reaction with acrylonitrile it was found t h a t the l a t t e r can g r a f t on to the fibre, giving a weight increase of up to 84 per cent. This increase in weight was o b t a i n e d with samples ozonised for not less t h a n an hour, and this indicates t h a t this m o n o m e r needs a larger n u m b e r of " a c t i v e " centres for effective c o p o l y m e r i z a t i o n t h a n was f o u n d earlier when its grafting on to c a p r o l a c t a m fibre was examined. EXPERIMENTAL SECTION *
F o r the purpose of the investigation, m a n u f a c t u r e d fibres and fihns of lavsan were used. T h e l a t t e r h a d a thickness of 0-20 to 0.40 /1. T h e m e t h o d of work was t h e same as t h a t used earlier. T h e final samples were boiled in benzene, washed in t h e same solvent and dried to c o n s t a n t weight at 55-60°C.
76
V.V. KORSHAKet al.
Samples (0.2000-0.3000 g) were treated with ozone, heated with styrene in a stream of purified nitrogen at 80°C, then boiled in benzene and dried to constant weight. The change of properties was established by measuring the increase in weight, change in mechanical, thermochemical and optical properties, viscosity, elemental analysis etc. The authors express their gratitude to [.V. Obreimov, G.L. Slonimskii and L.Z. Rogovina for help in carrying out mechanical and optical studies on the samples. CONCLUSIONS ([) In the case of polyethyleneterephthalate (lavsan) and vinyl monomers the possibility of obtaining graft copolymers from polyesters was observed, using ozone to initiate the polymerization. (2) A mechanism for the reaction of graftiug vinyl monomers on to polye t h y l e n e t e r e p h t h a l a t e has been proposed. (3) The data, obtained earlier on polyamides, has confirmed t h a t the yield of graft copolymer depends on the degree of orientation in the material under consideration. (4) I t was found t h a t of the vinyl monomers studied, styrene gives the highest yields of the graft copolymer. Translated by Z. K0WSZUN REFERENCES
1. V.V. KORSHAK and K. K. MOZGOVA, Izv. Akad. Nauk SSSR Otd. khim. nauk 651, 1958
2. V.V. KORSHAK, K. K. MOZGOVAand M. A. SHKOLINA, Dokl. Akad. Nauk SSSR 122: 609,
1958
3. V. V. KORSHAK, K. K. MOZGOVA and M. A. SHKOLINA, Vysokomol. soedin. 1: 1364, 1959 4. L. BELLAMY, Infrakrasnye spektry molekul. (Infra-red Spectra of Molecules.) Izd. in lit. 53, Moscow, 1957 * Zazechkina and Volkova participated in the experimental work.
(Received 18 June 1959) IN the present investigation the conditions for the synthesis of graft copolymers, from industrial materials was studied, using ozone as an activator for the polymerization. As the subject of our study we used a polyester--polyethylene terephthalate ("lavsan"), used in the form of thin films and fibres. As with polyamides, the initial samples of polyesters were treated with ozone and then heated in a stream of nitrogen, with styrene, acrylonitrile, vinylyd e n e chloride and vinyl acetate. The method used has been described previously [1-3]. DISCUSSION OF RESULTS
The investigation showed a distinct possibility of applying the given method of grafting not only to the series of polyamides, but also to a series of polyesters. I t was found that styrene easily grafts on to the polymer giving a graft eopolymer with a conversion of up to 60 per cent. Moreover, films and fibres of lavsan, even without activation with ozone, react with styrene giving a graft eopolymer but with a lower conversion. A similar phenomenon, was observed earlier with a series of polyamides when samples reacted with vinyl monomers without being ozonised [3]. As we have shown in the study of polyamides, this reaction takes place with samples of industrial products in which active centres occur. The formation of the latter is caused by various factors--destructive oxidation, presence of impurities, ete--as a result of which peroxide and hydroperoxide groups are formed in the polymer. Table 1 shows the change in weight of sample films of lavsan after copolymerization with styrene; Table 2 - - t h e same data shown for fibre samples of "lavsan". Examination of these Tables shows that the yield of graft copolymers varies little with different samples of films. * Vysokomol. soedin. 1: No. 11, 1604-1609, 1959. 70
Grafting of vinyl monomers on polyethylene terephthalate
TABLE 2. GRAFTING OF STYRENE ON TO LAYSAN FIBRES (5 IIR AT 80cC IN A STREAM OF NITROGEN)
TABLE 1. GRAFTING OF STYRENE ON TO LAVSAN FILMS (5 HR AT 80°C IN A STREAM OF NITROGEN)
Ozonization Time (rain)
Increase in weight (%)
0 5 10 6o
1.04 0.78
71
Ozonization
I n c r e a s e in weight after
. . . . . . . .
]
Time (rain)
grafting (0/0) 46"79 43"76 52"61 52"84
I n c r e a s e in
weight (°o)
0 5 10
-
[ncrease in weight after grafting (q~,) 17'01
-
0-39 0"25
23"38 39"81
C o m p a r i n g these results with the d a t a found for the fibres, it can be seen t h a t for t h e l a t t e r the yield of the c o p o l y m e r is lower t h a n t h a t for the films. These facts agree with the observations m a d e b y us on a series of polyamides, a n d t h e y are a p p a r e n t l y explained b y the different degree of o r i e n t a t i o n of films and fibres a n d t h e r e s u l t a n t o p p o r t u n i t y for the materials to absorb the monomer. W e suggest t h a t the i n t e r a c t i o n of the ozonised polyester with the vinyl m o n o m e r occurs as the result of the f o r m a t i o n of a h y d r o p e r o x i d e , w h i c h decomposes to give a free radical, which t h e n initiates the polymerization. W e t h i n k t h a t the graft p o l y m e r based oll lavsan and s t y r e n e is formed by the following mechanism: ....
OCH2CH~OOCCeH4CO--...-~ ()~ ~ . . .
--OCH 2--CH--()OC--C6 H~--CO-- . . . ---,
I
t --4 . .. OCH,CHOOCC6H4CO-- . . . CH~:- CHR ]
O"
~ . .
OOH . --()CH~CH OOC(~sH4CO-- . . . ---, I ()CH~--CH--
J
R
I t is obvious t h a t this process of f o r m a t i o n of a graft polylner m a y not de* velop in such a simple way as t h a t indicated b y the a b o v e mechaifism. I t is possible t h a t o t h e r parallel reactions occur simultaneously. I n Table 3 are given the changes f o u n d on testing the mechanical properties of the original films of lavsan and films a f t e r grafting on of styrene. Analysis of the above d a t a leads us to the conclusion t h a t if the sample of polyester is ozonised for a short time (5 min) t h e n its elongation increases as a result of c o p o l y m e r i z a t i o n with styrene, although its stability towards breaking decreases. T h e c o p o l y m e r o b t a i n e d from prolonged ozonisation of the sample, becomes more brittle (elongation decreases), possibly on account of the g r o w t h of a layer o f p o l y s t y r e n e , and the resistance to breaking increases slightly (apparently, as a result of linking of the p o l y m e r chains u n d e r the influence o f ozone).
T2
V.V. KORSHAKet al. TABLE 3. CHANGEIN MECHANICALPROPERTIES OF FILM AND FIBRE SAMPLES OF LAVSAN, AFTER OZONIZATION AND GRAFTING ON OF STYRENES FO/TII
of mate rial
Original sample %
kg/em z
Film Film Fibre
192.7 192.7 16.6
1552 1552 5852
The same sample after Time of ozonization and grafting ozonization of styrene (min) % I kg/em2 5 300 5
280 192.1 31
876.4 1115.0 4018
M e a s u r e m e n t of the film thickness o f the samples before a n d a f t e r grafting showed t h a t it increased from 19-20/~ for the initial samples to 32-38/~ for the final samples. D u r i n g t h e s t u d y o f the t h e r m o - c h e m i c a l properties o f lavsan it was f o u n d t h a t , a f t e r the grafting on o f styrene, it began to melt at a higher t e m p e r a t u r e , a l t h o u g h this increase is not so m a r k e d as in the case of amide G-669 and s t y r e n e (Fig. 1). T h e d a t a in Table 4 show t h a t with an increase in the time of ozonization t h e viscosity o f lavsan solution g r a d u a l l y increased, which is explained b y the
~,~'o 100 ~-
Y
50
gO 30 ¢0 50
100
/ 5 ~ T e m p e r a t u r(°C) e~
J
gO0
~
FIG. 1. Thermo-mechanical curves of samples of lavsan films. (1) Initial sample; (2) After treatment with styrene, cross-linking of chains u n d e r the influence of ozone. After the t r e a t m e n t of t h e ozonised sample w i t h s t y r e n e t h e specific viscosity of its solutions b e c a m e even higher, a p p a r e n t l y as the result of f o r m a t i o n of new chains, p r o b a b l y m u c h longer, p a r t i a l l y b r a n c h e d and even cross-linked.
.73
Grafting of vinyl monomers on polyethylene terephthalato
TABLE 4. CHANGE IN VISCOSITYOF 0"50/0 SOLUTIONOF SAMPLEIN CRESOL AFTER OZONIZING AND GRAFTING ON OF STYRENE (5 HR AT 80~C IN A STREAM OF NITROGEN) Time ofozonizing: 5 rain rhp before tl~p after copoly- - - .~ • .. / merization with- II " after ! tlsp alter o z o n l z f l ~ [ IOYI I out ozonizing I ozonizing eopo~ymerl, !, I zation qsp
0.248* 0-272t
]
I ,
- -
0-705
"
•
0"273 --
0"464 0.742
•
Times of ozonizing: 5 hr ...... , ............. q~p after i tlsp after ozonizing iI copolymerization i! i
0-305 --
0.610 --
• viscosity measured in 1957; solvcnt-m--cresol, t Viscositymeasured in 1959; solvent tri-crcsol.
Grafting of polystyrene on to samples of lavsan which occurred with a noticeable absorption, was found to change the elementary structure of the original polyester. T a b l e 5 s h o w s t h e c h a n g e in t h e e l e m e n t a r y s t r u c t u r e o f t h e g r a f t e d s a m p l e s compared with the original: after grafting of styrene a noticeable increase of t h e c a r b o n c o n t e n t ( u p t o 10 p e r c e n t ) a n d h y d r o g e n c o n t e n t is o b s e r v e d in t h e samples. Growth of a surface layer of polystyrene on the polyester not surprisingly altered the ease with which the grafted polymers are wetted by various solvents. A n o t i c e a b l e d e c r e a s e in w e t t i n g o f t h e s a m p l e s b y s o l v e n t s s u c h a s b e n z e n e , chloroform and dioxane was discovered. TABLE 5. CHANGE IN '[tie ELEMENTAL ANALYSISOF FILM AND FIBRES OF LAVSAN BEFORE AND AFTER OZONIZING AND TREATMENT WITH STYRENE F o r m of material
Fibre Fibre Fihn
Composition of original sample (%) C
H
62-13 61'95 61"95
4"18 4"19 4-19
62.52 62.53
4.30 4.48
Time of ozonizing I (rain) 5 l0 60
Composition of grafting Copolymer ( ° / o )
!---C-i---H 68.29 68.30 71.47 71.72 73" 11 72-87
Calculated for (CIoHsO4) (%)
.... l - - c 5.01 4-99 5.40 5.43 5.45 5.47
...... i - - H - - - -
62.50
4.19
T h e s t u d y o f t h e o p t i c a l p r o p e r t i e s o f film s a m p l e s s h o w e d t h a t t h e i n f r a - r e d s p e c t r a o f g r a f t p o l y m e r s differ f r o m t h e s p e c t r a o f t h e o r i g i n a l s a m p l e s b y c h a n g e s i n t h e r e g i o n o f 705 a n d 765 c m -1. A p p e a r a n c e o f n e w a b s o r p t i o n m a x i m a a t t h e s e w a v e l e n g t h s is e v i d e n c e that the polyester acquires frequencies which are characteristic of the monos u b s t i t u t e d b e n z e n e d e r i v a t i v e s . F r o m t h e d a t a o f B e l l a m y [4], t h e s e f r e q u e n c i e s
74
V.V. KOI~SHAKet aL
represent the non-planar deformation vibrations of the C - - H bonds. The I.R. absorption spectra are shown on Fig. 2a, b and e. Study of the same samples in the U.V. region of spectrum shows a certain difference caused by the grafting of polystyrene; the absorption curve for ]avsan
t
.)
J j.-.~
76C
,/
780 800
\ f
7 \
8tO
)
s"
('
i"
g2g
r"-
5"
960 r."
,
)
7 ~"
z..~i
~.'f
~
j f.-
-
3
C
~
o zc,ogo80100
Absorption % a
g 20 c g # o s o l g o
Absorption% b
60 60 80 100
Absorption % c
FIG. 2. Infra,red absorption spectra. (a) Initial sample of lavsan film; (b) The same sample after treatment with styrene, without ozonisation; (c) After treatment with styrene with preliminary ozonisatiorl for 10 min.
is however very indistinct and therefore these changes are illsufficiently characteristic. Changes in U.V. absorption of the samples is shown in Fig. 3a and 3b. The ease of grafting of other monomers on to ozonised samples of lavsan was studied for the fibres of this polyester and such monomers as vinyl acetate
Grafting of vinyl monomers on polyethylene terephthalate
75
a n d vinylidene chloride. I t was f o u n d t h a t b o t h m o n o m e r s g r a f t on to the fibres v e r y weakly; this is in a g r e e m e n t w i t h our observations on t h e i n t e r a c t i o n o f
T .... ~_ -
xg
I ,I I I
•
I
tl
inIT[[IIl
I I
-c9 t11tll
t
oz
-
o.!
3b ~,raa!xd3 0)' ~ "
Z5
' 'Z'5'
a
Sg~.oY~.lg3
5
FIG. 3. Ultra-violet absorption spectrum. (a) Initial sample of lavsan fihn; (b) The saxne sample after treatment with styrene: (1) without ozonising; (2) sample previously ozonised for 10 rain. TABLE 6. TREATI~IENT OF LAVSAN FIBRES WITH V1NYLIDENE CHLORIDE (5HR AT 30°C IN A STREA~I OF N2)
Ozonization
TABLE 7. TREATMENT OF LAVSANFIBRE WITH VINYL ACETATE (5HR AT 75°C IN A STREAM OF N2)
Ozonization
Increase in
Time (rain)
I n c r e a s e in w e i g h t (%)
weight after g r a f t i n g (%)
0 5 300
-()'39 2.09
1-78 0.93 None
Time (rain)
Increase in
I n c r e a s e in w e i g h t (%)
weight after grafting(%)
0 5 30
-0.18 --
1"94 1.31 3'00
300
2.05
None
these m o n o m e r s with p o l y a m i d e s [31. The e x p e r i m e n t a l results obtained are given in Tables 6 and 7. On s t u d y i n g the same reaction with acrylonitrile it was found t h a t the l a t t e r can g r a f t on to the fibre, giving a weight increase of up to 84 per cent. This increase in weight was o b t a i n e d with samples ozonised for not less t h a n an hour, and this indicates t h a t this m o n o m e r needs a larger n u m b e r of " a c t i v e " centres for effective c o p o l y m e r i z a t i o n t h a n was f o u n d earlier when its grafting on to c a p r o l a c t a m fibre was examined. EXPERIMENTAL SECTION *
F o r the purpose of the investigation, m a n u f a c t u r e d fibres and fihns of lavsan were used. T h e l a t t e r h a d a thickness of 0-20 to 0.40 /1. T h e m e t h o d of work was t h e same as t h a t used earlier. T h e final samples were boiled in benzene, washed in t h e same solvent and dried to c o n s t a n t weight at 55-60°C.
76
V.V. KORSHAKet al.
Samples (0.2000-0.3000 g) were treated with ozone, heated with styrene in a stream of purified nitrogen at 80°C, then boiled in benzene and dried to constant weight. The change of properties was established by measuring the increase in weight, change in mechanical, thermochemical and optical properties, viscosity, elemental analysis etc. The authors express their gratitude to [.V. Obreimov, G.L. Slonimskii and L.Z. Rogovina for help in carrying out mechanical and optical studies on the samples. CONCLUSIONS ([) In the case of polyethyleneterephthalate (lavsan) and vinyl monomers the possibility of obtaining graft copolymers from polyesters was observed, using ozone to initiate the polymerization. (2) A mechanism for the reaction of graftiug vinyl monomers on to polye t h y l e n e t e r e p h t h a l a t e has been proposed. (3) The data, obtained earlier on polyamides, has confirmed t h a t the yield of graft copolymer depends on the degree of orientation in the material under consideration. (4) I t was found t h a t of the vinyl monomers studied, styrene gives the highest yields of the graft copolymer. Translated by Z. K0WSZUN REFERENCES
1. V.V. KORSHAK and K. K. MOZGOVA, Izv. Akad. Nauk SSSR Otd. khim. nauk 651, 1958
2. V.V. KORSHAK, K. K. MOZGOVAand M. A. SHKOLINA, Dokl. Akad. Nauk SSSR 122: 609,
1958
3. V. V. KORSHAK, K. K. MOZGOVA and M. A. SHKOLINA, Vysokomol. soedin. 1: 1364, 1959 4. L. BELLAMY, Infrakrasnye spektry molekul. (Infra-red Spectra of Molecules.) Izd. in lit. 53, Moscow, 1957 * Zazechkina and Volkova participated in the experimental work.