不同分子质量聚乳酸立体复合物的结晶性能及球晶形貌  

Crystallization behavior and spherulites morphology of stereocomplexed poly(lactic acid) s with different molecular weights

作　　者：戈欢 朱志国[1] 王锐[1,2] 尹会会[2] 王睿[1] 张秀芹[1] 

机构地区：[1]北京服装学院材料科学与工程学院,北京100029 [2]四川大学高分子材料科学与工程国家重点实验室,四川成都610065

出　　处：《纺织学报》2016年第2期27-34,共8页Journal of Textile Research

基　　金：北京市属高等学校创新团队建设与教师职业发展计划项目(20140502);北京服装学院校内科研重点资助项目(2012A-02);北京市教委-北京服装学院研究生科研创新项目(X2014-089)

摘　　要：同等质量的L-乳酸（PLLA）和D-乳酸（PDLA）共混后,能够形成立体复合聚乳酸（PLA）。研究了5种不同相对分子质量（0.6×10~4~1.2×10~5）的PLLA和PDLA共混物的热性能、结晶动力学以及球晶的形态结构。聚合物均是通过L-LA或D-LA熔融-固相聚合相结合的方法获得。与相应的均聚物比较,PLLA和PDLA溶液共混后形成的立体复合PLA具有更好的结晶性能和更高的熔点。分别以5、10、20、30℃/min为降温速率进行结晶动力学研究,发现较高分子质量样品具有更好的结晶速率,可能是因为样品中分子链在结晶发生之前具有更快的链复合能力。最后,通过偏光显微镜成功地在较低分子质量sc-PLA球晶结构中观察到了可逆的裂纹现象,证明裂纹的出现与结晶过程中形成的晶体间内应力有关。Stereocomplex poly（lactic acid） （sc-PLA） could form in the mixture of poly（L-lactide） （PLLA） and poly（D-lactiole） （PDLA） at a mass ratio of 1：1. In this paper, the thermal properties, crystallization kinetics and spherulites morphologies of the mixtures with different molecular weights （0. 6 × 4 - 1.2 × 105, homopolymers） were studied. All the homopolymers were prepared from L-LA or D-LA by melt condensation. Compared to corresponding homopolymers, sc-PLA formed by solution blending of PLLA and PDLA show much better crystallinity and higher melt temperature. The crystallization kinetics of the mixtures were investigated by DSC cooling scan at the rates of 5, 10, 20, and 30 ℃/min. The results showed that the samples with higher molecular weight, possess faster rates of crystallization, which should be ascribed to the better ability of stereocomplexation between the enantiometric chain segments prior to occurrence of crystallization. Finally in the study, the spherulites morphologies of mixtures were investigated on polarizing microscope. Cracks formed in the samples with lower molecular weight. The temperature-dependant reversibility of cracks might be resulted from the inner stress due to too fast cooling rates.

关 键 词：聚乳酸立体复合物 热性能 结晶动力学 裂纹球晶 

分 类 号：O631.2[理学—高分子化学]