Determination of a Kinetic Model for the Polyaddition of Bisphenol A with an Epoxide Liquid Resin

Abstract

Solid epoxy resins are produced at Vantico SA by catalyzed reactions of a low-molecular weight liquid resin (RBL) with bisphenol A (BPA). These reactions lead to solid epoxy resins, which are used in surface coatings or adhesives. The chain lengthening step (advancement reaction) is based on the reaction of the epoxy functional group with the phenolic hydroxyl group leading to the formation of a secondary hydroxyl group. These secondary hydroxyl groups can also react with epoxy groups to form branched molecules. This paper presents a kinetic model describing the transformation of BPA with a RBL up to complete conversion of BPA. The polymerization kinetics is investigated by isothermal measurements for temperatures between 180 and 210°C and for different initial concentrations of BPA. A reaction scheme describing both the advancement and the branching reactions has been developed. For modeling the branching rate, a detailed diffusional and semiempirical model has been adapted and modified in order to fit the experimental results.