Surface modification of vulcanized styrene–butadiene rubber with trichloroisocyanuric acid solutions of different active chlorine contents

Abstract

Two solutions in ethyl acetate (EA) containing 3 wt% trichloroisocyanuric acid (TCI) from two different suppliers having different active chlorine contents were used as chemical surface treatment of a vulcanized styrene–butadiene (SBR) rubber. The amount of active chlorine in the TCI solutions was evaluated by iodine titration. The changes produced in the SBR rubber were monitored by using ATR-IR spectroscopy, scanning electron microscopy and contact angle measurements. The adhesive strength variation in SBR rubber/polyurethane adhesive joints was consistent with the variation in surface chemistry, wettability, and topography of the treated SBR rubber. The increase in time between TCI solutions preparation and SBR treatment allowed an increase in adhesive strength, the highest value corresponded to the joint produced with the SBR rubber treated with TCI solution prepared for 60 days. On the other hand, the active chlorine concentration in the TCI solutions was not the only parameter determining the adhesion of SBR rubber, as the highest adhesive strength was not achieved by treating the rubber with the TCI solution with higher active chlorine content. Therefore, the effectiveness of the halogenation treatment of rubber was not always higher by using a halogenating solution with higher active chlorine content. Furthermore, the chlorine concentration in the TCI solutions was not stable in the course of time, 60 days after preparation of solutions was the most efficient chlorinating solution for SBR rubber surface modification.