Polyester polyol-based polyurethane adhesive; Effect of treatment on rubber surface

Polyester polyols were synthesized using vegetable oil fatty acids having different characteristics (mainly in terms of hydroxyl functionality) and epoxy resin, using triethylamine as a catalyst. Polyols were characterized by the FTIR spectroscopy. Polyurethane adhesives were synthesized from it and used in bonding rubber. Treatment of sulphuric acid on the non-polar styrene butadiene rubber (SBR) surface was studied for the bond strength improvement via an increase in wettability of the rubber surface. Wettability was found by measuring the contact angle using Goniometer. Bond strength was evaluated by a 180degrees T-peel test. The surface modification and mode of bond failure were studied by Scanning Electron Microscopy (SEM). The synthesized polyurethane adhesives were compared with the commercial adhesive.