Abstract

Polychloroprene has been in commercial use for over 65 years, but continues to be the elastomer of choice for dynamic applications requiring moderate heat and oil resistance, or where long-term environmental resistance is required. The material is manufactured by emulsion polymerization of 2-chloro-1,3-butadiene. The properties of the product can be optimized for specific end uses by selection of polymerization conditions, by use of comonomers such as 2,3-dichlorobutadiene and methacrylic acid, and by choice of the method used to control molecular weight. The kinetics of the polymerization process and the structure of the polymer have been studied in detail and related to polymer properties. Commercial products vary widely in properties depending on the intended end use and the details of the manufacturing process. Tough crystalline or ionomeric polymers are preferred for adhesive applications, whereas softer, more flexible polymers are preferred for mechanical goods applications. The latter polymers may be compounded and fabricated by substantially all the techniques used for manufacture of rubber goods by molding, extrusion, or calendering operations. Latexes are used for various bonding and adhesive applications as well as for dipped goods requiring toughness in the unreinforced film. Monomers can undergo runaway reactions so strict handling procedures must be followed.