A Simple Approach for Preparation of High-yield Butadiene-Maleic Anhydride Copolymer Microspheres by Suppressing Diels-Alder Reaction

The burgeoning ethylene production in the Asia-Pacific region has led to a substantial oversupply of butadiene as a byproduct, and it is highly important to develop new butadiene-based materials. Butadiene-maleic anhydride copolymer, characterized by its amphiphilic nature, shows potential applications in adhesives, emulsifiers, etc. However, the Diels-Alder (DA) reaction of butadiene and maleic anhydride competes with the polymerization, limiting the copolymer yield. In this study, the kinetics of the DA reaction and copolymerization between butadiene and maleic anhydride were examined, and the influence of various reaction conditions on the copolymer yield was investigated. We found that the DA reaction in the induction period of the radical polymerization was the critical factor in limiting copolymer yield. Therefore, we proposed the two-step method to suppress the DA reaction and achieve high-yield production (∼85%) of cross-linked microspheres with controllable particle size (175–800 nm) by self-stabilized precipitation polymerization. This work enables an efficient synthesis of conjugated diolefin-maleic anhydride cross-linked microspheres, offering a novel approach to address the issue of butadiene overcapacity.