Adhesion between dissimilar polymers. II. Effects of bonding temperature and crosslinking agent

We study the effects of bonding temperature and crosslinking agent on the adhesion of a crosslinkable BIMS polymer (terpolymer of isobutylene, p‐bromomethylstyrene, and p‐methylstyrene) to a crosslinkable diene polymer, such as polyisoprene rubber (IR) or polybutadiene rubber (BR). The strength of adhesion between these two dissimilar polymers, represented by the work of detachment, Ga, is measured by using the T‐peel geometry at various test temperatures and separation speeds. Surface‐sensitive infrared‐visible sum frequency generation (SFG) spectroscopy is used to characterize the surface of BIMS and ensure the existence of crosslinkable species, the p‐bromomethylstyrene functional group, on this polymer. Time‐of‐flight secondary ion mass spectroscopy (ToF‐SIMS) is utilized to determine the loci of failure of the debonded surfaces and the influence of curative migration, if any, on adhesion. Although a zinc di‐2‐ethylhexanoate crosslinkable BIMS polymer shows interfacial crosslinking or cocure when bonded to a sulfur crosslinkable diene polymer at 140°C, interfacial cocure does not occur when the bonding temperature is raised to 180°C. On the other hand, if the sulfur crosslinking agent in the diene polymer is replaced by another crosslinking agent, a brominated phenolic resin, interfacial cocure occurs between BIMS and the diene polymer when the bonding temperature is 140, 160, or 180°C. Also, this brominated resin cocures the BIMS and diene polymer phases when these immiscible polymers are blended together in the presence of a metal compound (salt) of carboxylic acid, such as zinc di‐2‐ethylhexanoate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 323–335, 2004