选用辛酸亚锡[ Sn（ Oct）2]和钛酸四丁酯（ TBT）作为聚乳酸（ PLA）／聚碳酸亚丙酯（ PPC）的酯交换反应催化剂，研究了溶液条件下单一催化剂及复合催化剂对PLA／PPC酯交换反应的催化作用。通过对反应产物的分子结构、热力学及流变学行为进行分析，结果发现，无论在单一催化剂还是复合催化剂作用下， PLA与PPC分子间均发生了酯交换反应，同时伴随着断链反应。其中，当Sn（Oct）2作为单一催化剂或Sn（Oct）2／TBT作为复合催化剂时，样品更倾向发生断链反应而非显著的酯交换反应。进一步分析纯样品在催化剂Sn（ Oct）2或TBT作用下的反应情况，结果发现， PPC在反应最初阶段以高分子量的分子链断链为主，且会发生明显的解拉链降解，从而导致PLA／PPC在等质量比时酯交换反应程度不高，这为今后更好地研究PLA／PPC酯交换反应提供了思路。%Stannous octoate [ Sn ( Oct ) 2 ] and tetrabutyl titanate ( TBT ) were selected as transesterification catalysts to investigate the transesterification of poly( lactic acid) ( PLA)/ poly( propylene carbonate) ( PPC) blends. From the gel permeation chromatography(GPC) and 1H nuclear magnetic resonance(1H NMR) results of pure PLA, PPC under the catalysis of Sn( Oct) 2 or TBT, it was found that PLA mainly had chain scission under Sn( Oct) 2 catalyzing while intramolecular transesterification under TBT catalyzing. PPC mainly showed chain scission, mostly in high molecular weight molecule chains, under two kinds of catalysts, and the catalysis activity of TBT was more effective than that of Sn(Oct)2. Considering the transesterification of PLA/PPC catalyzed by Sn(Oct)2, TBT or composite catalyst[Sn(Oct)2/TBT], respectively, a certain extent of transesterification under any catalyst would be realized, accompanied by chain scission. PLA/PPC with Sn (Oct)2 or Sn(Oct)2/TBT was given priority to chain scission rather than transesterification, but TBT could promote the transesterification mainly. Due to the chain scission of neat PPC under any single catalyst mostly happened in high molecular weight molecules chain, a lower transesterification degree could be obtained when the mass ratio of PLA/PPC was 1∶1, which would be a good guidance to further improve the degree of transes-terification between PLA and PPC.
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