Synthesis of High-Molecular-Weight Maleic Anhydride-Based Copolymer Esters by Intermolecular Double-End Esterification with Diols

Maleic anhydride (MAH) copolymers have a wide range of applications in various fields. However, the difficulty in obtaining high-molecular-weight (Mw) copolymers through polymerization often limits their potential for application expansion. In this paper, diols were chosen as chain extenders to increase the Mw of MAH copolymers through esterification reactions between anhydride and alcohol, achieving the goal of “chain extension”. As the reaction progressed, the double-end esterification content (DEC) increased and the Mw showed exponential growth accompanied by an increase in gel content. The effects of various reaction parameters, including the temperature, reaction time, types and amounts of diols, polymer concentration, and Mw of raw polymer, on the Mw and gel content of the product were investigated systematically. Furthermore, this method can effectively increase the Mw of various mixed olefin–MAH copolymers. The experimental results demonstrated that the Mw of raw polymers could be increased by up to 70 times (from 18.0 to 1270.8 kg/mol), thereby broadening the polymers’ potential applications.