Synthesis, Structure and Properties of Isobutylene Oxide-CO₂ Copolymer

Isobutene oxide (IBO) is a derivative of isobutene that is an important C4 product in petrochemical industry. The preparation of aliphatic polycarbonates by the copolymerization of IBO with carbon dioxide (CO2) is a feasible way to utilize isobutene and CO2 with high added value, but only few studies have been reported so far. In this paper, heterogeneous Zn-Co bimetal cyanidation complex (Zn-Co DMCC) was used to catalyze the copolymerization of IBO with CO2 at 40 degrees C, and the catalytic efficiency was up to 1.6 kg copolymer/g DMCC. The product of poly(butyl carbonate) (PIBC) had a fully alternating structure and a regional regularity of 95%. The number-average molecular weight was up to 18.6 kDa, and the lowest content of cyclic by-product was 7 mol%. PIBC is a crystalline polymer with a melting point of 93.7 degrees C, but the crystallization rate of PIBC is slow. The initial thermal decomposition temperature of PIBC is only 145 degrees C. The tensile strength of PIBC is 4.4 MPa and the elongation at break is 350%. Therefore, PIBC may be used in sacrificial adhesives. DMCC also catalyzed the copolymerization of CO2, IBO and maleic anhydride (MA) to obtain a fully alternating terpolymer. The results provide a new sustainable development path for the application of isobutene. [GRAPHICS]