本文研究了苎麻纤维含量对苎麻纤维增强聚乳酸复合材料性能的影响规律和增强机理。通过注塑成型制备了10-40 wt% 纤维含量的复合材料试样，并采用多种材料表征方式对其进行表征测试。研究表明：苎麻纤维的添加提高了复合材料的耐热性能；此外，苎麻纤维均匀地分在基体中，由于纤维与聚乳酸弱的界面强度，断面上有大量的纤维拔出和孔洞；差示扫描量热仪测试表明高含量的纤维限制了聚乳酸分子链的运动，促进复合材料形成更加致密完善的晶核；同时，流变行为也表明苎麻纤维含量的增加有助于提高复合材料的黏弹响应和复合黏度；最后，苎麻纤维的加入提高了复合材料的拉伸和弯曲强度，且随纤维含量的增加而增大，与聚乳酸相比，当纤维含量为40 wt%时 复合材料的拉伸和弯曲强度分别提高了22.9 % 和21.9 %。
This study investigated the influence of the fiber loading on the properties of ramie fiber reinforced poly (lactic acid) composites and strengthening mechanism. The composites reinforced with ramie fiber (10—40 wt%) were fabricated by the injection molding and several tests were performed. The results indicated that the heat resistance of the composites was improved by blending the fibers. In addition, the ramie fibers were uniformly distributed in the matrix, but there were numerous fibers pull-out and holes in the fractured surface due to the poor interfacial adhesion between the fibers and PLA. Differential scanning calorimetry showed that the high fiber loading in the composites restricted the movement of PLA molecular chain and promoted the formation of the perfect crystal. At the same time, the high content fiber contributed to enhance the viscoelastic response and complex viscosity of the composites. Finally, the tensile and flexural strengths of the composites were improved with the increasing fiber loading. Compared with PLA, the incorporation of 40 wt% fibers increased the tensile and bending strengths of the composites by 22.9% and 21.9% respectively.