Chlorosulfonated Polyethylene

Abstract

AbstractChlorosulfonated polyethylene represents a group of chemically modified polyolefins containing pendent chlorine and sulfonyl chloride groups and having useful synthetic elastomer properties. They are derived from the action of a mixture of chlorine and sulfur dioxide, sulfuryl chloride and a weak base, or sulfuryl chloride and chlorine on preformed polyolefin polymers in the presence of an initiator. Although the reaction is normally carried out batchwise in a carbon tetrachloride solution, other solvents and process schemes have been successfully used. The resulting polymer may contain 20–60% chlorine and 1–5% sulfur as sulfonyl chloride groups. The pendent chlorine atoms serve to destroy the parent polymer crystallinity and impart useful chemical properties such as resistance to oil, oxidizing chemicals, ozone, and heat. The sulfonyl chloride groups react with divalent metal oxides, sulfides, or radical traps to form stable cross‐links. The raw polymer and vulcanizate mechanical properties are controlled by the molecular weight, molecular‐weight distribution, and chain branching of the parent polyolefin.The technology has been extended to include copolymers and functionally grafted homopolymers as base resins. These new types, along with extensive studies combining the flexibility of the sulfonyl chloride cure site with specific cross‐linking agents, stabilizers, and reinforcing agents, have produced a broad array of useful products, ie, coatings, adhesives, hose, tubing, automotive belts, etc.