Copolymerization of Butadiene with Vinyl Monomers

Abstract

M o s t copolymers of butadiene (75 parts) with vinyl monomers (25 parts) are rubbery, but the quality of the elastomers varies greatly with the nature of the vinyl monomer. Of four comonomers herein described 2-vinylthiophene and methacrylonitrile form copolymers which compare favorably with GR-S; 2-vinylfuran and vinylidene chIoride do not. The copolymer with Z-vinylfuran is different from GR-S; it is benzene-insoluble, produces high modulus and low elongation stoclcs, and has inferior flexcracking resistance. The copolymer with 2-vinyIthiophene is similar in properties to GR-S. The methacrylonitrile copolymer is also similar, but superior to GK-S in respect to the baIance between hysteresis-temperature rise and flex-cracking resistance. The butadiene-vinylidene chloride copolymer is poorer than GR-S in this respect.HE copolymerization of butadiene with a large variety of vinyl monomers has been of much recent interest in the search for new and useful synthetic rubbers. In the present work are described the copolymers of butadiene with two analogs of styrene, 2-vinylfuran, and 2-vinylthiophene, as well as with methacrylonitrile and vinylidene chloride. STARTING MATERIALS%VINYLFURAN was furnished by E. C. Lathrop of the Northern Regional Laboratories and was distilled directly before use; b.p. ~-VINYLTHIOPHEND was prepared by the catalytic dehydration with potassium hydroxide of 2-(2-hydroxyethyl)-thiophene. The latter compound was furnished us by C. A. Weisgerber of Pennsylvania Strtte College. The apparatus and technique are those described by Frank, Adams, Allen, Gander, and Smith (1). From 258 grams (2.01 moles) of 2-(%hydroxyethyl)-thiophene were obtained, at 165' C. and a pressure of 120 * 5 mm., 200 grams of crude ZvinyIthiophene, This was dissolved in chloroform, the water layer separated, and the chloroform solution dried over anhydrous caIcium chloride. The dried product was distilled through a 6-inch helix-packed column, and 115.5 grams (53%) of Zvinylthiophene were obtained; b.p. 75" C. at 75 mm.; ny 1.5733; di0 1.037; molecular refraction calculated 34.28, found 35.00. Analysis: Calculated for C6H6S, c 65.45, H 5.45; found C 65.28, H 5.36. Microanalyses were carried out by Howard Clark of the Illinois State Geological Survey. Kuhn and Dann

Copolymerization.

“…In connection with the Government-supported research on synthetic rubber, Professor C. S. Marvel and his associates at the University of Illinois (69,117,118) have made a large number of copolymers in emulsion at 50°C. from feeds containing 75 per cent by weight of butadiene and 25 per cent of various substituted styrenes to replace the unsubstituted styrene used in GR-S.…”

Preparation and Polymerization of Vinyl Heterocyclic Compounds

“…The reaction conditions are similar to those of the dehydration of a-hydroxyethyl derivatives, and the reactions are carried out in general at higher temperature under reduced pressure. (42) [2 31 , 1-vinylpyrrole ( 40.5) [24] , 1-vinylindole (23.6) [24], 9-vinylcarbazole (92) [25], 2-vinylthiophene [15,26] (53 [27], 80 [28] 1, 2-vinyl-4-methylthiophene (95) [28], 2-vinyl-5-t-butylthiophene (94) [28], 2-vinylimidazole ( 11.9)[29], 2-vinyl-1-methylimidazole (75)[29], 2-vinylpyridine (81) [30-321, 4-vinylpyridine (56)[19], 2-vinyl-5-ethylpyridine (63)(64)(65)(66)(67)(68)(69)(70)(71) [ 331 , 2-vinyl-4,6-dimethylpyridine (89 1341, 78 [19J), 2-vinylquinoline (49 [21], 57 [32]), 2-vinylpiperidine [31], 2-vinyl-1-methylpiperidine [31,35,36], 2-vinyl-l-ethylpiperidine [37], 4-vinylpyrimidine ( 23.4) [38], vinylpirazine (80) [39], 2-N ,N-dimethylamino-4-vinylpyrimidine (46.7) [38 ] , 2-vinyloxazoline [454] , 2-isopropenyloxazoline [455] . C .…”

“…Preparation of 5-tricyanovinyltetrazole by reacting an inorganic azide with a nitrile was reported [502]. Copolymerization of 2-vinylfuran with butadiene in emulsion gave a rubbery product, which can be easily cross-linked in the presence of oxygen [27]. Copolymerization with chloroprene was studied at 50°C in emulsion, using sodium perborate as an initiator [249].…”

“…A rubbery product was obtained from 2-vinylthiophene and butadiene. The analysis of the copolymers shows that the former enters the copolymer at rates approximately proportional to its concentration in the monomer mixture [271]. 3-Vinylthiophene was also prepared from 3-methylpentane and sulfur dioxide passing over a Ca-Ni phosphate catalyst at 550" C [272].…”