工程科学学报.第43卷.第7期：952-959.2021年7月 Chinese Journal of Engineering,Vol.43,No.7:952-959,July 2021 https://doi.org/10.13374/j.issn2095-9389.2021.03.02.002;http://cje.ustb.edu.cn 苎麻纤维增强聚乳酸复合材料性能研究 展江湖，王迎宵，杨志浩，李姣四，林军，王桂龙，管延锦 山东大学材料科学与工程学院，济南250061 ☒通信作者，E-mai:lijiao_87@163.com 摘要通过密炼-注塑成型工艺制备了不同苎麻纤维含量的聚乳酸基复合材料，研究了纤维含量对复合材料性能的影响规 律，并揭示了纤维增强机理.研究表明，芒麻纤维的添加提高了复合材料的耐热性能，尤其是当纤维质量分数为40%时，复合 材料的热变形温度提高了10.5%.此外，苎麻纤维均匀地分散在基体中，由于纤维与聚乳酸的界面强度较弱，断面上有大量的 纤维拔出和纤维孔洞：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，当纤维质量分数为40%时复合材料的拉伸和弯 曲强度分别提高了30%和21.9% 关键词苎麻纤维：力学性能：纤维增强：微观结构：流变行为 分类号TG142.71 Effect of fiber content on the properties of ramie fiber reinforced poly (lactic acid) composites ZHAN Jiang-hu,WANG Ying-xiao,YANG Zhi-hao,LI Jiao.LIN Jun,WANG Gui-long.GUAN Yan-jin School of Material Science and Engineering,Shandong University,Jinan 250061,China Corresponding author,E-mail:lijiao_87@163.com ABSTRACT Natural fiber,as an alternative to synthetic fiber,is of great potential to reinforce composites that are applied in engineering fields such as automotive aerospace,automotive,sports,packaging,medical,and construction due to their renewability, environmental friendliness,high specific strength,and modulus.To realize this potential,ramie fiber reinforced poly (lactic acid)(PLA) composites with different fiber loadings were fabricated by injection molding.The heat deformation temperature,microstructure, crystallization behavior,rheological behavior,and mechanical properties of the composites were also analyzed.Results indicated that the heat resistance of the composites was improved with increased fiber loading.Particularly,the heat deformation temperature of the composites was improved by 10.5%when fiber with mass fraction of 40%was blended into the matrix.In addition,there were numerous fiber pull-outs and holes in the fractured surface due to poor interfacial adhesion between the fibers and PLA.Meanwhile,ramie fibers were uniformly distributed in the matrix when incorporating a low fiber content,but fiber agglomerations occurred in the matrix when introducing a high fiber loading (mass fraction of 40%)because of the poor wettability between the fibers and PLA.Differential scanning calorimetry (DSC)showed that the high fiber loading in the composites restricted the movement of the PLA molecular chain and promoted the formation of the perfect crystal.At the same time,samples with a high content of fiber contributed to the enhancement of the storage modulus,loss modulus,and complex viscosity of the composites due to the fibers'physical joint in the matrix.Finally,the tensile and flexural strengths of the composites were improved with increased fiber loading.However,when the mass fraction of loading 收稿日期：2021-03-02 基金项目：国家自然科学基金资助项目(52005299)：波音-商飞联合资助项目(2019-GT-169)苎麻纤维增强聚乳酸复合材料性能研究 展江湖，王迎宵，杨志浩，李    姣苣，林    军，王桂龙，管延锦 山东大学材料科学与工程学院，济南 250061 苣通信作者，E-mail: lijiao_87@163.com 摘    要    通过密炼−注塑成型工艺制备了不同苎麻纤维含量的聚乳酸基复合材料，研究了纤维含量对复合材料性能的影响规 律，并揭示了纤维增强机理. 研究表明，苎麻纤维的添加提高了复合材料的耐热性能，尤其是当纤维质量分数为 40% 时，复合 材料的热变形温度提高了 10.5%. 此外，苎麻纤维均匀地分散在基体中，由于纤维与聚乳酸的界面强度较弱，断面上有大量的 纤维拔出和纤维孔洞；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，当纤维质量分数为 40% 时复合材料的拉伸和弯 曲强度分别提高了 30% 和 21.9%. 关键词    苎麻纤维；力学性能；纤维增强；微观结构；流变行为 分类号    TG142.71 Effect  of  fiber  content  on  the  properties  of  ramie  fiber  reinforced  poly  (lactic  acid) composites ZHAN Jiang-hu，WANG Ying-xiao，YANG Zhi-hao，LI Jiao苣 ，LIN Jun，WANG Gui-long，GUAN Yan-jin School of Material Science and Engineering, Shandong University, Jinan 250061, China 苣 Corresponding author, E-mail: lijiao_87@163.com ABSTRACT    Natural  fiber,  as  an  alternative  to  synthetic  fiber,  is  of  great  potential  to  reinforce  composites  that  are  applied  in engineering  fields  such  as  automotive  aerospace,  automotive,  sports,  packaging,  medical,  and  construction  due  to  their  renewability, environmental friendliness, high specific strength, and modulus. To realize this potential, ramie fiber reinforced poly (lactic acid) (PLA) composites  with  different  fiber  loadings  were  fabricated  by  injection  molding.  The  heat  deformation  temperature,  microstructure, crystallization behavior, rheological behavior, and mechanical properties of the composites were also analyzed. Results indicated that the heat  resistance  of  the  composites  was  improved  with  increased  fiber  loading.  Particularly,  the  heat  deformation  temperature  of  the composites was improved by 10.5% when fiber with mass fraction of 40% was blended into the matrix. In addition, there were numerous fiber pull-outs and holes in the fractured surface due to poor interfacial adhesion between the fibers and PLA. Meanwhile, ramie fibers were uniformly distributed in the matrix when incorporating a low fiber content, but fiber agglomerations occurred in the matrix when introducing  a  high  fiber  loading  (mass  fraction  of  40%)  because  of  the  poor  wettability  between  the  fibers  and  PLA.  Differential scanning calorimetry (DSC) showed that the high fiber loading in the composites restricted the movement of the PLA molecular chain and promoted the formation of the perfect crystal. At the same time, samples with a high content of fiber contributed to the enhancement of the storage modulus, loss modulus, and complex viscosity of the composites due to the fibers’ physical joint in the matrix. Finally, the tensile and flexural strengths of the composites were improved with increased fiber loading. However, when the mass fraction of loading 收稿日期: 2021−03−02 基金项目: 国家自然科学基金资助项目（52005299）；波音−商飞联合资助项目（2019-GT-169） 工程科学学报，第 43 卷，第 7 期：952−959，2021 年 7 月 Chinese Journal of Engineering, Vol. 43, No. 7: 952−959, July 2021 https://doi.org/10.13374/j.issn2095-9389.2021.03.02.002; http://cje.ustb.edu.cn