SYNERGIZED THERMAL STABILIZATION EFFECT OF ACID ACCEPTORS ON PEROXIDE CROSSLINKED CHLOROPRENE RUBBER

Abstract

Chloroprene rubber (CR) vulcanizates have been widely used in various industrial applications due to their excellent mechanical properties such as elasticity, elongation at break, and superior resistance to chemicals, flame, etc. Because of the specific microstructures of CR, it is mainly vulcanized by metal oxide vulcanizing systems. However, CR undergoes rapid thermal degradation when it is crosslinked by peroxide curing systems at high temperatures. Although peroxide curing systems such as dicumyl peroxide (DCP) have attracted tremendous attention in the vulcanization of various saturated and unsaturated elastomers to achieve high-performance engineering properties, it is avoided for CR due to the occurrence of thermal decomposition, which is catalyzed by hydrochloric acid (HCl) vapors released during crosslinking. In the present work, by exploiting different acid acceptors, attempts have been made to design a vulcanizing system composed of inorganic–organic materials as acid acceptors to increase the potential of hindering the thermal decomposition in the CR phase. The designed system provides an accelerated system with a high crosslink density and mechanical properties comparable to metal oxide cured CR with elongation at break of ∼1000% and tensile strength of 10.3 MPa. The extent of thermal stabilization in the CR phase provided by the designed acid acceptor system was studied with thermogravimetric analysis.