木质素接枝右旋聚乳酸的结晶行为及对左旋聚乳酸的结晶促进作用

木质素（lignin）作为仅次于纤维素的第二大可再生生物质资源，近年来受到广泛关注并已被应用于高分子材料的改性。本文在对碱木质素烷基化修饰的基础上，利用其丰富的羟基对右旋丙交酯进行开环聚合，制备了一系列不同分子量的烷基化木质素接枝右旋聚乳酸（LGPD）。通过对LGPD自身结晶行为的研究表明，木质素的存在能够促进右旋聚乳酸（PDLA）的结晶，提高其吸收紫外线的能力。相对于4臂右旋聚乳酸（4a-PDLA），将LGPD作为添加剂加入到左旋聚乳酸（PLLA）后更有利于立构复合晶的形成，从而进一步提高了共混材料的结晶能力。

Crystallization behavior of lignin-grafted-poly(D-lactide)and its promotion effect on poly(L-lactide)crystallization

As the second most plentiful renewable biomass resource after cellulose, lignin has received extensive recent attention and has been used in the modification of polymer materials. In this work, lignin-grafted-poly(D-lactide) (LGPD) materials with different molecular weights have been synthesized by D-lactide ring-opening polymerization using a modified alkaline lignin alkylation process. The crystallization behavior of the products was studied by differential scanning calorimetry (DSC). The results showed that the presence of lignin accelerated the crystallization of PDLA and enhanced its UV-absorbing ability. Compared with a four-arm poly(D-lactide) (4a-PDLA), LGPD was better able to promote the formation of stereocomplex crystallites (SC) with poly(L-lactide) (PLLA) and thus improved the crystallizing ability of the material.