Abstract
This paper deals with some of the applications and more or less unusual physical properties of several of the commercial rubber-like synthetic materials on the market or in advanced stages of development at the present time. The materials which are considered as “synthetic rubbers” fall into four classes: (a) Buna S types or copolymers of butadiene and styrene; (b) Buna N types, or copolymers of butadiene and acrylonitrile; (c) Neoprenes, or polychloroprenes, or copolymers of chloroprene with other materials; and (d) Butyl rubber, a copolymer of isobutylene and butadiene. The Thiokols or organic polysulphide polymers might be included among the “synthetic rubbers” by some, but, although they appear to be vulcanizable, their thermoplasticity makes them useful only to a limited degree in places where elasticity and other rubber-like properties at higher temperatures are desired. Details concerning Buna S type polymer, adopted by the Rubber Reserve Company for use in tires and as a general-purpose rubber, are discussed. Some interesting data on the efficiencies of various synthetic rubber compounds as compared to those of natural rubber compounds at high and low temperatures are shown. Data are also given which indicate that the proper choice of plasticizer is important for compounds to be used for oil-resistant gaskets, sealing rings, and the like.
