Crosslinking ofXNBRlatex with multifunctional epoxides: An energy‐efficient curing strategy for the fabrication of accelerator‐free rubber gloves

Abstract

AbstractHerein, we pursue an efficient curing strategy using multifunctional epoxides, which undergo a nucleophilic ring opening reaction across the free COOH groups of a carboxylated nitrile butadiene rubber (XNBR). Following a prevulcanization protocol, we cure the rubber in the latex phase at 60°C. Thin films are then prepared by using a conventional coagulant dipping process, in which the final cure degree of the elastomer is reached during drying (postvulcanization). In a comprehensive approach, cure kinetics, tensile properties, and crosslink density of the thin elastomer films are studied as a function of the functionality and concentration of the applied crosslinker. The results clearly show that films with high tensile strength (39 MPa) are obtained without prevulcanization. Stability tests reveal that the shelf life of the latex formulations is limited to less than 1 day due to hydrolysis reactions of the epoxy groups of the water‐soluble crosslinker. However, the storage stability can be extended to several days if nonwater‐soluble epoxy crosslinkers are applied. The decent shelf life together with the fast cure rates and excellent mechanical properties make epoxy crosslinking a promising curing strategy for preparing dipped rubber gloves without hyperallergenic accelerators used in classical sulfur vulcanization.