1532
INDUSTRIAL AND ENGINEERING CHEMISTRY
The effects of variations in the zinc oxide, sulfur, and mercaptobenxothiazole concentration on the sulfur combining rates were determined. It was found that a marked induction period exists, during which the zinc me1 captide of mercaptobenzothiazole, the initial product, reacts readily with sulfur. The ratio of combined sulfur to consumed niercaptobenzothiazole is constant during the vulcanization process. A kinetic expression is given which accounts for the data. When polyisobutylene was substituted for GR-S or Hevea, the zinc mercaptide of mercaptobenaathiazole was found to be the initial product. A mechanism is postulated for the accelerating properties of mercaptobenzothiazole. I t involves the formation of the zinc mercaptide, which reacts with sulfur and rubber t o regenerate mercaptobenzothiazole and form sulfur-rubber compounds. ACKNOWLEDGMENT
The author wishes to el;press his sincere appreciation to earl Parks for experimental assistance and to 8. D. Gehman for Buggestions and encouragement. He also wishes to thank H. J.
Vol. 45, No. 7
Ostcrhof and the Goodyear Tire and Rubber Co. for permission to publish this work. LITERATURE CITED
Adams, H. E., private communication, May 29, 1952. Clark, G. L., Le Tourneau, R. L., and Ball, J. M.,IND.ENG CHEM., 35,198 (1943). Davis, C. D., and Blake, J. T., “Chemistry and Technology of Rubber,” Chap. IX, Kevv York, Reinhold Publishing Corp., 1937.
Dufraisse, C., and Houpillart, J., Rea. g6n. caoutchouc, 19, 207 (1942). Petrov, K. D., J . A p p l . Chem. (U.S.S.R.),16, 214 (1943). Petrov, K. D., Rubber Chem. and Technol., 17, 56 (1944). Wistinghausen, L. V., Kautschuk, 5, 57, 75 (1929). Zeide, 0. A., and Petrov, K. D., Rubber Chem. and Technol., 11, 97 (1938). RECEIVED for review February 26, 1953. ACCEPTED April 3 , 1353. Presented before the Division of Rubber Chemistry. AMERICAN CHEMICAL SOCIETY, Buffalo, N. Y . , October 1352. Work performed as a part of the research project sponsored b y the Reconstruction Finance Corp., Office of Synthetic Rubber, in connection with the synthetic rubber program. Contribution 137, Research Laboratory, Goodyear Tire and Rubber Co.
olymerization of Alpha, BetaUnsaturated Ketones BENZALACETOPHENONE AND OTHER KETONES COPOLYMERIZED WITH BUTADIENE AND OTHER MONOMERS C. S. MARVEL, W. R. PETERSON, H. I
