聚乳酸/剑麻复合材料流变性能表征

Characterization of rheological properties of polylactic acid/sisal fiber composites

利用转矩流变仪测量流变特性的方法,表征了不同剑麻纤维含量下,聚乳酸(PLA)/剑麻复合材料的流变性能,并测量实验后纤维的长度和宽度、PLA分子量,分析剑麻纤维含量和转速对复合材料体系中纤维长度的影响,以及PLA降解情况。结果表明,复合材料的非牛顿指数在纤维含量为10%左右出现峰值,并进一步随含量的增加而减小。复合体系中,刚性剑麻纤维受到来自于转子、聚合物和纤维之间的作用力,纤维被剪短,长径比减小;聚乳酸会受到转速和纤维含量的影响发生降解,这些因素都会影响PLA/剑麻复合材料的流变性能。

Rheological properties of polylactic acid/sisal fiber composites with different sisal fiber mass fraction were evaluated by the method of torque rheometer rheological properties testing.The lengths and widths of sisal fibers in the composites and the molecular weights of polylactic acid,including the processed materials and unprocessed PLA were measured.The effect of sisal fiber mass fraction and rotor speed on the length of sisal fiber inthe composites were analysed.The degradation status of polylactic acid was also analyzed.The results showed that the non-Newtonianindex of composites presented a peak at the sisal fiber mass fraction about 10 %,then decreased with further increasing mass fraction.In the composites ,because of the forces that were applied on the rigid sisal fiber by rotor ,polylactic acid melt and interaction among fibers ,the sisal fibers were snipped and the length-diameter ratio decreased.In addition,polyactic acid degraded due to the effect of rotor speed and sisal fiber content.These factors affected the rheological properties of polylactic acid/sisal fiber composites .