摘要：

In combination with methyllithium,ring-opening polymerization(ROP) of L-lactide(L-LA) and copolymerization of ε-caprolactone(ε-CL) and L-LA were investigated in the presence or absence of benzyl alcohol by using an air-stable zinc complex bearing(benzimidazolyl) pyridine alcohol ligand. Similar to the polymerization of ε-CL,the monomers were completely converted to polymers in short time in all the cases and high catalytic activities were achieved in the ROP of L-LA. The structural analysis of polymers indicated that in the absence of benzyl alcohol,the polymers obtained were mainly cyclic PLA with relatively broad molecular weight distribution, whereas linear PLA with lower molecular weight and narrower molecular weight distribution predominated in the presence of benzyl alcohol. On the basis of ROP of ε-CL and L-LA,the ring-opening copolymerization of ε-CL and L-LA was studied with the different CL/LA feeding ratios. A series of linear and cyclic block copolymers with different CL/LA molar ratios was synthesized by the sequential feeding strategy according to the presence or absence of benzyl alcohol in the reaction system. The structure and thermal properties of homopolymers and copolymers were characterized by FTIR,1 H NMR,13 C NMR,GPC,DSC and TGA analysis.

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