"Effect of regulating crosslinking degree of acrylic rubber on properties of acrylic rubber/polyoxymethylene thermoplastic vulcanizates"

Acrylate rubber (ACM)/polyoxymethylene (POM) thermoplastic vulcanizates (TPV) were prepared by dynamic full-vulcanization process with ACM, POM and thermoplastic polyurethane elastomer as raw materials, and hexamethylene diamine carbamate (HMDC) as vulcanizing agent, and the effects of the crosslinking degree of ACM on its curing characteristics and the physical and mechanical properties, dynamic mechanical properties, aging resistance, oil resistance and mechanical relaxation characteristics of ACM/POM TPV were investigated by regulating the HMDC amount. The results showed that with the increase in the HMDC amount, the torque during ACM vulcanization increased and the crosslin-king degree of ACM increased. When the HMDC amount was 1.8 phr (mass, similarly hereinafter), tensile strength of ACM/POM TPV reached the peak value, storage modulus increased and loss modulus decreased, non-relaxable modulus of tensile stress relaxation increased significantly, and relaxation rate decreased. When the HMDC amount was 2.1 phr, the aging resistance of ACM/POM TPV was the best, and the change rates of tensile strength and elongation at break after thermo-oxidative aging were 2.87% and-4.05%, respectively, while the change rates of tensile strength and elongation at break after hot-oil aging were -6.89% and -3.38%, respectively.