Effect of Composition on Adhesion and Chemical Resistance in Multilayer Elastomer Laminates

Abstract

The defense against dangerous chemical agents imposes demanding requirements for the development of protective materials, such as elastomers, plastics, and fabrics. While chemical protective clothing is commercially available, its elasticity, flexibility, stretchability, and chemical resistance spectrum may be restrictive and in need of further improvement. In this paper, a multilayer elastomer laminate, consisting of bromobutyl rubber (BIIR), acrylonitrile-butadiene rubber (NBR), and a fluoroelastomer (FKM), was fabricated to meet broad-range protection against chemical agents, while remaining flexible and stretchable. The bonding between the multiple layers was investigated via formulations designed to promote interlayer adhesion. The effects of magnesium oxide (MgO), zinc oxide (ZnO), stearic acid, carbon black, and phosphonium salt on the vulcanization and adhesion of the BIIR–NBR–FKM laminate were systematically studied using cure rheometry and T-peel tests. The optimized formulations of each rubber yielded adhesion strengths of 19 N/2.5 cm and >65 N/2.5 cm for the BIIR–NBR laminate and NBR–FKM laminate, respectively. The chemical resistance of these three elastomer sheets and their strongly bonded laminates was measured according to ASTM F739 and the time-lag method for methyl ethyl ketone, toluene, and butylamine. The laminates showed excellent resistance to the selected chemicals, with detected breakthrough times of longer than 1000 min. Also, some laminates were observed to have longer breakthrough times than the equivalent thickness of the individual elastomers making up the laminate.