细菌纤维素/聚乳酸互穿网络复合材料的结晶与熔融

为了研究细菌纤维素(BC)网络结构对聚乳酸(PLA)结晶与熔融过程的影响,以PLA为基体,BC为增强体,通过PLA-三氯甲烷溶液与BC-无水乙醇分散液的共混扩散制备了具有互穿网络结构的BC/PLA生物复合材料。采用SEM、偏光显微镜(POM)、DSC和莫志深(MO)模型研究了复合材料的微观形态、球晶形貌、非等温结晶动力学和熔融行为。结果表明:采用溶液共混扩散法可得到以BC为骨架、PLA缠绕其表面的互穿网络结构的复合材料。随降温速率增加,BC/PLA复合材料的结晶温度、熔融温度和相对结晶度均下降。BC可作为异相成核剂,适量添加可同时提高BC/PLA复合材料的结晶速率和相对结晶度,细化球晶尺寸。MO模型可较好地描述BC/PLA复合材料的非等温结晶动力学行为。

Crystallization and melting of bacterial cellulose/polylactic acid composites with interpenetrating network

In order to research the influence of bacterial cellulose (BC) network structure on crystal and melting process of polylactic acid (PLA), PLA and BC were selected as the matrix and the reinforcement to prepare BC/PLA biological composites with interpenetrating network structure via blending diffusion of PLA-chloroform solution and BC-anhydrous ethanol dispersion. The micro-morphology, spherulite morphology, non-isothermal crystallization kinetics and melting behavior of the composites were investigated by SEM, polarized optical microscopy (POM), DSC and MO's model. The results show that the solution blending diffusion method is available for the preparation of composites with interpenetrating network structure of PLA wound on the surface of BC skeleton. The crystallization temperature, melting temperature and relative crystallinity of BC/PLA composites decrease with the increasing of cooling rate. As a heterogeneous nucleating agent, proper amount BC can improve the crystallization rate and relative crystallinity and refine the spherulite simultaneously. MO's model can describe the non-isothermal crystallization kinetics behavior of BC/PLA composites very well.