Lipase-catalyzed liquid solid synthesis of poly(butylene succinate)

Poly(butylene succinate) (PBS) was successfully synthesized by the polycondensation reaction from 1, 4-butanediol and succinic acid in a liquid solid reaction system catalyzed by Novozyme435 which is a kind of immobilized lipase. The influences of reaction conditions were investigated. The weight-average molecular weight M̄_w and the polydispersity M̄_w/M̄_n of PBS were measured by GPC, and the molecular structure of product was analyzed by ¹H-NMR spectroscopy. The optimum reaction conditions found are as follows: the molecular ratio of succinic acid to 1, 4-butanediol is 17/23, the mass dosage of Novozyme435 used is 7%(wt, vs. total substrate), the suitable solvent is diphenyl ether (200%(wt), vs. total substrate), the reaction temperature, pressure and time are 65°C, -0.01 MPa (under vacuum) and 48 h, respectively. Under above optimum reaction conditions, the PBS with the maximum M̄_w of 50800 (M̄_w/M̄_n=1.36) was produced. The experimental results show that the extent of PBS dissolution in reaction medium and the exclusion of by-product water are the most important factors for the polycondensation of PBS.