Solid epoxy resins are produced by catalyzed reactions of a low-mol.-wt. liq. resin (RBL) with bisphenol A (BPA). These reactions lead to solid epoxy resins that have many uses. The chain lengthening step (advancement reaction) is based on the reaction of the epoxy functional group with the phenolic hydroxyl group and leads to the formation of a secondary hydroxyl group. These secondary hydroxyl groups can react with epoxy groups to form branched mols. The aim of the present study is to develop a kinetic model describing the transformation of BPA with a RBL up to complete conversion of BPA. [on SciFinder (R)]