Lipase-catalyzed synthesis of aliphatic poly(β-thioether ester) with various methylene group contents: thermal properties, crystallization and degradation

A series of novel aliphatic poly(beta-thioether ester)s with various methylene group contents were prepared by direct lipase-catalyzed polycondensation of the monomer with an acid-labile beta-thiopropionate group. The polycondensation reaction using immobilized lipase B from Candida antarctica was carried out in diphenyl ether at 90 degrees C. Poly(beta-thioether ester)s with high molecular weights of 20 500-57 000 Da and narrow polydispersities in the range 1.40-1.48 were obtained. Thermogravimetric analysis, differential scanning calorimetry and wide-angle X-ray diffraction were used to investigate the thermal properties and crystal structures of these polyesters. All the poly(beta-thioether ester)s were semicrystalline polymers and thermally stable up to at least 200 degrees C. In vitro degradation studies showed that they can rapidly degrade under acidic conditions by the hydrolysis of the beta-thiopropionate groups, suggesting their potential as acid-degradable polymeric materials. (c) 2019 Society of Chemical Industry