Ammonium Salt Catalyzed Crosslinking Mechanism of Acrylic Rubbers

Abstract

Abstract Crosslinking mechanisms of acrylic rubber containing both carboxylic and epoxy curing active sites were studied on low molecular weight polymers using different recipes. High cure rates were obtained with quaternary ammonium salts and/or triaryl nucleophiles of Group Va elements. A reaction mechanism based on carboxylate onium salt activity was suggested. Very high reaction rates were obtained with catalysts having low basicity and high steric hindrance, whereas polyamines like o-tolylbiguanidine were less effective. A very simple method for scorch time regulation was devised.