Polymerization of methyl acrylate, methacrylonitrile and acrylonitrile, initiated by KNH2 in solution, suspensions of LiNH2 and Ba (NH2)2 in liquid NH3, and by solid KNH2

470

YE. •. ZVYAGINTSEVAand A. I. SHATENSHTEIN CONCLUSIONS

(1) A study has been made of structure formation in a polyamide copolymer (l~ylons 6; 6,6 and 6,10) from various solvents. (2) At all temperatures of preparation of the specimens only fibrillar formations arise and the crystals also have a fibrillar structure. (3) By etching of specimens with formic acid it was possible to distinguish elementary components of the fibrillar formations, of width ~ 100 A. Tran,slate,d by E. O. PHILLIPS REFERENCES 1. 2. 3. 4.

D. V. BADJLNH and P. H. HARRIS, J. Polymer Sei. 41: 540, 1959 F. gHOUl{Y, J. Polymer Sci. 26: 375, 1957 A. KELLER, J. Polymer Sci. 17: 392, 1955 M. B. KONSTANTINOPOL'SKAYA, Z. Y&. BERESTNEVA and V. A. KARGIN, Dokl. Akad. Nauk SSSR 151: 1108, 1963 5. V. V. KORSHAK and S. A. PAVLOVA, Izv. Akad. Nauk, Otd. khim. nauk, 1107, 1955

POLYMERIZATION OF METHYL ACRYLATE, METHACRYLONITRILE AND ACRYLONITRILE, INITIATED BY KNH2 IN SOLUTION, SUSPENSIONS OF LiNH2 AND Ba (NH~)2 IN LIQUID NHs, AND BY SOLID KNH~* Y E . N. ZVYAGINTSEVA a n d A. I . SHATENSHTEII~ L. Ya. Karpov Physicochemical Institute

(Received 7 May 1964)

IN A PREVIOUS communication [1] we showed that the molecular weight (MW) of polymethylmethacrylate (PMMA) obtained by polymerization initiated by amides of alkali and alkaline-earth metals is dependent on the phase state of the amide (solution or suspension in liquid NHs, or solid amide without solvent). The presence of a solid phase (even in the presence of a large quantity of liquid l~rHs) caused a considerable increase in the MW of the polymer. The question arises whether this is true for monomers other thall MMA. We have carried out experiments on the polymerization of methyl acrylate (MA), methacrylonitrile (1VIAl) and acrylonitrile (AN) in a solution of KNH~, in suspensions of Li_N~2 and Ba(NH2) ~ in liquid NH s and on solid KNH~. Control experiments were carried out on MMA, confirming the previous results. * Vysokomol. soyed. 7: :No. 3, 423-426, 1965.

Polymerization of methyl acrylate

471

Great attention was paid to the purity of the monomers, some of which were specially prepared. Experiments were usually carried out with several preparations of each monomer. The experimental method [1] was improved to give more standardized conditions of polymerization. Care was taken to eliminate traces of oxygen and moisture. Polymerization of MAN and AN gave coloured products, and the colour depended on the experimental .conditions. The yield of the polymers in solution was normally 70-100 ~ and in the suspensions 50-80 ~ , but with solid KNH~ it was strongly dependent on the quantity of initiator even for a given visible surface area of the latter. For brevity we shall omit the experimental details and observations. The molecular weights were calculated by means of the following formulae P1K1K/k: [t/]c~c~'----4.S5x10-5 M°'8°;

PMA: [t/]c~.H':l'28x 10-~ M°'714;

P1KA~: [t/]DoM.®~3"06 x 10 -3 M°'6°3;

PAN: [t/]v~e~- 2"43 x 10-4 M °'Ts.

The polymers of MAN and AN obtained in 0.06 1~ KNH2 solution and the PAN formed on the suspension of LiNH~ were not completely soluble in dimethylformamide (DM'F) even at 60 °. The residue, consisting of 30-50~ of the total weight of polymer, was filtered off, and for the calculation of [~] a correction was made for the weight of insoluble material. In all other cases these polymers were completely soluble in DMF. The molecular weight of the PMA~ prepared by Overberger [2] in KNH2 solution had a considerably lower MW ((7-18) × 10-3) t~lan in our work. Sample I I I (less pure) gave a polymer of MW close to those of reference [2]. RESULTS AND DiSCUSSiON

Table 1 shows typical results (No. denotes the monomer sample number and m the molar ratio of monomer to amide). They are semiquantitative in nature mainly because it is impossible to standardize the true surface area of the solid amide (in suspenion or without solvent), and there are no methods for determining it. Nevertheless the average MW values shown in Table 2 give a characteristic picture. We give least weight to the results for PMA because we could not obtain very pure samples of the monomer. Change in the phase state of the system in which polymerizatin occurs does not have the same effect on the molecular weight of polymers of different chemical composition. Thus the value of MW in the polymerization of MMA on suspensions of LiNtIz and Ba(NH2) ~ is close to the MW of the polymer formed on solid KNH~, but this is not true for MA. The molecular weight of PMA~ obtained by polymerization in 0.004 N KNH~ solution differs little from that of the polymer obtained with an LiNH z suspension, but MW is greater for polymerization on a Ba(NHa) 2 suspension and on solid K_NH~. Polymerization on solid KNH 2 without solvent gives polymers of considerably higher molecular weight than are obtained by polymerization in solutions of

472

YE. N. ZVYAOI~TSEVAand A. I. SHATENSHTEIN TABLE 1. RESULTS OF POLYMERIZATIONEXPERIMENTSAT Solution (0.06 :N)

No.

m

I I II

20 17 20

'

t

[r/]

Suspension of amide

x I0 -a amid

I

: :. J=i

-

-

50 o

Solid KNI-I,

-a

] X 10 -3

Methyl acrylate 0.040 0-032 0.040

Ba

Ba Li Li Li

"II II II Ii II

3 3

1010.036 2010.03~

lll0.10C 17 0.088 15 0.052

II 9

II* II* II

20 20 0.8 0.4

II* II* II §

0.6 0.3 0.5

7.3 9.3 10.8

5200 8400 11300

30 20 0.9 1.3

5.9 4.8 5.7 7.1

700 530 670 900

I*

0.076 I 0-0791 0.080 / o.275

8 8 9 46

5

Methacrylonitrile I I 1II lit nt

17 12 12 210 250

2"20 1.98 0"20 1.30

1.80

480 380 4 170 320

Ba

I

Ba Ba Li Li Li

I II II

II II:

20 16 18 20 20 23

3.50 7.30 8.37 2.30 2"35 1'99

1200 5200 6800 520 540 390

Acrylonitrile I I II

20 20 20

0"82 0"75 0.72

50 45 43

Sa

Ba Ba

I I I

21 I 0.28 2010.59 20 0.51

12 33 27

I*

I* I I

* 20°; t C'KN'H,=0.004N; ~ Yield 84%; § Yield 28%. this s o l v e n t . T h e s a m e r e s u l t w a s o b t a i n e d p r e v i o u s l y in e x p e r i m e n t s w i t h s t y r e n e [3, 4]. Since t h e i n i t i a t o r s o f p o l y m e r i z a t i o n in s o l u t i o n a n d o n s u s p e n s i o n s w e r e a m i d e s o f d i f f e r e n t m e t a l s , in o r d e r t o e l i m i n a t e t h e effect o f t h e g e g e n i o n a n d t o s h o w t h a t w i t h t h e s a m e c a t i o n t h e m o l e c u l a r w e i g h t o f P M M A is d e p e n d e n t o n t h e p h a s e s t a t e o f t h e a m i d e w e m ~ d e use o f t h e l o w s o l u b i l i t y o f l~al~H~ in l i q u i d a m m o n i a a t - - 7 0 ° ( ~ 0 . 0 1 mole/1.). F i v e t o s e v e n millilitres o f 0.01 N TABLE 2. MOLECULARWEIGHT(M r X 10-') OF POLYMERS PREPARED AT -- 50 ° Polymer

PMMA* PMA PMAN PAN

K_N-FI, solution

Suspension L i N H s Ba(NH,)s

40

900

3

8

300 50

500

1500 3

4000 20

Solid I~,

1300 5or 10,000 800

Polymerization of methyl acrylate

473

N a N H z solution were taken and the volume was reduced by a factor of 7-10 by evaporation of the solvent. Some of the I~aNH~ precipitated and the MMA was added afterwards. I n parallel experiments MMA was polymerized at --70 ° in 0.01 N I~aNTI~ solution and in these the volumes corresponded to the initial TABLE 3.

POLYM]CRIZATION OF ! ~ ] ~ A IN A SOLUTION AND SUSPENSION OF ~ a N H

NaNtI t solution No.

NaNH 2 suspension

n x CM I Yield V1 CM of pol-[ M v× ~ n× 1/1 x l0~ m ymer, [t/] x l0_ s V~ x104

% I I II

7.0 0-7 5.0 0.5

29 35 20 19

0.4 40 5.0 500 0.4 40 3.8 400

83 86 80 72

2 AT - - 7 0 °

m

I 0.50 0.75J 170 17 0.07 0-30 54

Yield of pol.3Iv x ymer, [t/] x l0_ 3

%

I 28 20

,o 400;57. ;0 40054.

m

82

1._41 380_

85

1.21] 314

* Thefirstnumberexpressesmin relationto the numberofmolesofNaNl~zin solutionand the second in relation to the NaNH~ present in suspension.

(V1) and final (V~) volumes of liquid in the experiments with NaNH~ suspensions (Table 3). I n Table 3 n is the number of moles of monomer, C M the monomer concentrations in mole/1, and the symbol ~ denotes the yield of polymer expressed as a percentage. I n these experiments two samples of MMA were used. These differed only in so far as the second had been in contact with air for some time. I n the solution experiments this resulted in considerable reduction in the MW of the polymer but had little effect on the molecular weight of the polymer obtained in the presence of the solid amide. Evidently the amide assists in removal of some chain terminating impurity. The same effect was observed previously in our laboratory in the polymerization of styrene [4]. Table 3 shows t h a t in the presence of the solid phase the molecular weight is increased considerably, particularly in the case of sample II. Polymerization can occur simultaneously on the surface of solid Nal~i-I 2 and in solution. Therefore the average molecular weight must be lower than would be obtained if the IqaXH~ were suspended in pure ammonia. Consequently it m a y be considered t h a t it has been proved t h a t if the initiator is in the form of a solid phase then regardless of the gegenion the molecular weight of some polymers is increased even in an excess of ammonia. A more detailed study of this effect would be of interest. We express our gratitude to Ye. A. Izraelevich who made improvements in the experimental method, to Z. 1~. Ovchinnikova who assisted in the experimental work, and to P. P. Alikhanov, L. Ya. Mashkova and G. G. Shcheglova for determining the purity of the monomers by the chromatographic method. CONCLUSIONS

(1) The polymerization of methyl acrylate, methacrylonitrile and acrylonitrile, initiated by a solution of K _ N ~ and suspensions of Li~H~ and Ba(N~z) ~ in

474

L . K . Ltr~V.¢ etag.

liquid I~H s , and by solid KI~H~ without a solvent, has been carried out at --50 °. Methyl methacrylate has been polymerized a t - - 7 0 ° in a solution of l~al~H2 in ammonia and on a suspension of ~ a ~ H 2 in this solution. (3) The extent to which the molecular weight of polymers obtained on suspensions of amides is greater than t h a t of polymers prepared in a solution of an amide differs for different monomers and rn~y be dependent on the cation of the initiator. (3) As a rule polymers of considerably higher molecular weight are formed on the surface of the solid amide than when polymerization is initiated by a solution of the amide in liquid ammonia. Translated by E. O. PHILLIPS REFERENCES 1. A. I. SHATENSHTEIN, Ire. N. ZVYAGINTSEVA and Z. N. OVCHINNIKOVA, Sb. Karbotsepnye vysokomolekulyarnye soyedineniya. (Collected Papers. Carbon-chain Macromolecular Compounds.) p. 189, Izd. Akad. Nauk SSSR, 1963 2. g. G. OVERBERGER, H. YUKI and N. URAKAWA, J. Polymer Sci. 45: 127, 1960 3. A. I. SHATENSHTEIN, Ye. A. YAKOVLEVA, Ye. A. KOVRIZHNYKH, P. N. MANOCH~INA and N. A. PRAVIKOVA, Vysokomol. soyed. 4: 42, 1962 4. A.I. SHATENSHTEIN, Ye. A. YAKOVLEVA and E. S. PETROV, Dokl. Akad. Nauk SSSR, 156: 882, 1961

SYNTHESIS AND PROPERTIES OF HETERO-ORGANIC POLYMERS WITH SILICON, GERMANIUM AND TIN IN THE CHAIN* L. K. LUNEVA, A. M. SLADKOV and V. V. KORSHAK Institute of Hetero-organic Compounds, U.S.S.R. Academy of Sciences

(Received 8 May 1964)

THE preparation of hetero-organic polymers containing double bonds in the chain, alternating with atoms of silicon, germanium or tin has been discussed previously [1-3]. For the preparation of such polymers we have made use of the reaction of addition of the hydrides of silicon, germanium and tin to unsaturated compounds. From the dihydrides of dialky](aryl)silicon, -germanium and -tin with bisacetylenes or bis-ethynyl and bis-propargyl derivatives of silicon, germanium and tin we have prepared polymers according to the general scheme (R----Alk, Ar; EI~Si, Ge, Sn): * Vysokomol. soyed. 7: No. 3, 427-431, 1965.