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 (M_w) copolymers through polymerization often limits their potential for application expansion. In this paper, diols were chosen as chain extenders to increase the M_w 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 M_w 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 M_w of raw polymer, on the M_w and gel content of the product were investigated systematically. Furthermore, this method can effectively increase the M_w of various mixed olefin-MAH copolymers. The experimental results demonstrated that the M_w 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.