QUEST FOR SUSTAINABLE CURATIVES FOR CHLOROPRENE RUBBER: A COMPREHENSIVE REVIEW

Chloroprene rubber (CR) is one of the most versatile synthetic rubbers suitable for numerous industrial applications. For years, zinc oxide (ZnO) has been satisfactorily used as the vulcanization activator for CR, typically with organic accelerator(s). Ethylene thiourea (ETU) is the most widely used accelerator, offering the best balance between cost and performance in CR vulcanizates. Recently, the ZnO level in rubber compounds has become a pressing issue because of its harmful environmental impacts. ETU is classified as a substance of potentially serious health risks. It is therefore imperative to identify sustainable crosslinking additives for CR from both technical and commercial standpoints. The key purpose of this review is to collate the significant lines of technological advances made to identify proecological curative options for CR and update the information up to the current year. In preparation for this review, pertinent scholarly articles on the curing of CR, published in scientific journals mainly in the past two decades, were assessed. Since the scope of this review is to capture the significant technical efforts available in the public domain, the reference list is therefore not necessarily an exhaustive one. Reports dealing with proprietary chemicals or undisclosed technical strategies are beyond the purview of this review.