N e w polymers with properties ranging from elastomers to rigids are suitable for high temperature applications. Blends of chlorinated polyethylenes are also evaluated for compatibility. orinated polyethylene is one of the few examples chemical substitution reaction on the backbone chain of the original polymer. The transformation is even more striking because by starting from one specific linear polyethylene a whole new series of polymers results whose properties depend on the degree and randomness of chlorine substitution. The new polymers range in propertics from elastomers to rigids with high glass transition temperatures suitable for high temperature applications. Furthermore, for the same degree of substitution, the polymers can be made to vary in degree of crystallinity allowing further control over mechanical properties. In the present article the broad range of mechanical properties available in this polymer system and the relationships of the properties to the degree of substitution will be discussed. Structure of Chlorinated Polyethylene