Preparation and adhesive properties of azoester-modified SBS triblock copolymers

Abstract

Styrene-butadiene-styrene triblock copolymer (SBS) has been modified by reaction with isopropyl azodicarboxylate (IAD). Tg of the butadiene block, tensile strength and stiffness of the block copolymer increase with modification level, which is attributed to increased polar interactions between the chains. Peel strength of Al laminiate and Nylon-6 laminate bonded with modified SBS was investigated. The incorporation of adequate amount of the IAD onto the block copolymer improves its adhesive strength over metal and nylon-6 substrate substantially. In the case of nylon-6/modified SBS joints, their bond strength increased with increasing contact time at a particular temperature range. It is suggested that in the temperature range of 160similar to200degreesC, there is a reaction between the carboxyl group of modified SBS and the amino group of nylon-6 to form interfacial chemical bonds, which controls the adhesion behavior of SEB-g-IAD/nylon-6 joints.