Accession Number : AD0669497

Title :   LABILE CROSSLINKS IN LOW UNSATURATION ELASTOMERS, II. EFFECT OF CHAIN AND CROSSLINK STRUCTURE ON THERMAL AND OXIDATIVE STABILITY,

Corporate Author : PRINCETON UNIV N J FRICK CHEMICAL LAB

Personal Author(s) : Lyons,Peter F. ; Lee,Timothy C. P. ; Tobolsky,Arthur V.

Report Date : APR 1968

Pagination or Media Count : 35

Abstract : The thermal and oxidative stability of low unsaturation elastomers was studied as a function of chain and crosslink structure by stress relaxation and oxygen absorption techniques. An ethylene-propylene-terpolymer, a propylene oxide copolymer, and an ethylene sulfide-propylene sulfide-terpolymer were used. The thermally labile polysulfide crosslink that results from sulfur cures is a potent antioxidant. The thermal lability is ascribed to an interchange mechanism, with an activation energy of 24 kcal/mole between 100 and 150C. The presence of an atom of oxygen in the chain results in an increased susceptibility to oxidative degradation compared with a hydrocarbon chain. The presence of a sulfur atom in the polymer chain confers a sensitivity to a destructive attack by the active ingredients and products of an accelerated sulfur curing recipe. (Author)

Descriptors :   (*ELASTOMERS, *CROSSLINKING(CHEMISTRY)), POLYETHYLENE PLASTICS, EPOXY RESINS, SULFIDES, POLYMERS, COPOLYMERIZATION, OXIDATION, THERMAL STABILITY, HEAT OF ACTIVATION, VULCANIZATION

Subject Categories : Polymer Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE