POLYMERIZATION OF (R,S)-BETA-BUTYROLACTONE FROM TETRAISOBUTYLDIALUMINOXANE (TIBAO) CATALYST

Poly-beta-hydroxybutyrate (PHB) was prepared by ring-opening polymeriz ation reactions of racemic beta-butyrolactone ((R,S)-beta-BL) using te traisobutyldialuminoxane (TIBAO). A study was conducted on the effects of catalyst concentration, polymerization time, polymerization temper ature, nature of solvent, modifications of the catalyst by water addit ion and TIBAO purification on the yield and molecular weights of the p olymer obtained. Optimal conditions for the synthesis of highest yield and molecular weights of the polymer were determined. By adding water to TIBAO, molecular weights increased but also polydispersities. Quan titative yields of crude PHB were obtained but reaction times required were long, molecular weights were quite low and molecular weight dist ributions were broad. A study of the TIBAO stereospecificity, the poly mers structure and morphology and their biodegradation will be conside red in future papers. Copyright (C) 1996 Elsevier Science Ltd