甲壳素纳米纤维/聚乳酸复合材料的制备及性能

Preparation and Properties of Chitin Nanofibers/Polylactic Acid Composite

利用甲壳素纳米纤维(CHNFs)对聚乳酸(PLA)进行增强改性,分别采用湿混法和聚乙二醇(PEG)分散剂法制备了挤出成型的CHNFs/PLA复合材料,并对复合材料的力学性能、热性能及微观形貌进行表征。结果表明,制备的α-甲壳素纳米纤维直径小于100 nm,长度为几百微米,具有三维网状结构;湿混法和PEG分散剂法对制备的CHNFs/PLA复合材料都有较好的增强作用,当CHNFs的添加量高于30%时,湿混法制备的复合材料的力学性能明显优于PEG分散剂法制备的复合材料;对复合材料的扫描电镜图分析表明,湿混法制备的复合材料中有大量的网状细丝均匀致密地分散在PLA的断面,达到了对CHNFs预期的分散效果,而PEG分散剂法制备的复合材料中,CHNFs以短小纤维的聚集体形态分布于复合材料的断面,说明聚乙二醇对于CHNFs与PLA体系是良好的界面相容剂,但是该方法降低了CHNFs的长径比。因此湿混法是一种更有效的纤维预处理方式。

Chitin nanofibers （CHNFs） reinforced polylactic acid （PLA） composites were prepared by the wet blending method and the polyethylene glycol（PEG） dispersion agent method. The properties of mechanical, thermal and microscopic for CHNFs/PLA composites were investigated. The results demonstrate that the diameter of obtained a-chitin nanofibers is less than 100 nm and the length is about several hundreds of micrometer with three- dimensional network structure. An ideal reinforcing effect can be achieved for CHNFs/PLA samples prepared by these two methods. When the content of CHNFs is higher than 30 %, the mechanical performance of the composite prepared by the wet blending method is better than that of the composite prepared by the PEG method. From the FE-SEM images, it is found that a large number of fibers are distributed on the fracture surface of PLA uniformly and compactly for the samples prepared by the wet blending method. For the samples prepared by the PEG method, some short fiber clusters are entangled with PLA matrix with no obvious phase separation between CHNFs and PLA. This observation reveals that PEG is a good interracial compatibilizer for CHNFs and PLA. However, the reinforcing effect is weaken due to decrement of the CHNFs aspect ratio for the PEG method, and the wet blending method is an effective pretreatment method for nanofibers.