A Novel System for Crosslinking Fluoroelastomers

The use of HBTBP as a crosslinking agent in fluoroelastomers has been reported. HBTBP was found to be especially suitable for FKM-G polymer, and the mechanism of crosslink formation in this fluoroelastomer was investigated. Compounding studies, swelling measurements, solvent extraction, and nitrogen tests have been used to tentatively shed light on the crosslinking mechanism. The results of these tests were used to propose mechanisms of crosslink formation occurring through a combination of: (i) radical abstraction of the methylenic hydrogen in FKM-G and crosslink formation through the interaction of the resulting radicals, (ii) interaction of a reactive intermediate from (i) with the raw FKM-G polymer, and (iii) nucleophilic substitution.