In the current study, three different types of biocomposites based on poly(lactic acid) (PLA) and short flax fiber were produced using extrusion. Alkali treatment was conducted on the flax fiber before the extrusion process in order to improve the interfacial adhesion between the flax fiber and the PLA matrix. The influence of the coupling agent and alkali treatment on the composite materials was investigated with regard to the mechanical, thermal and thermomechanical properties of the injected composites. The results show that the coupling agent has a favorable effect on the thermal, thermomechanical and mechanical properties of the composites. The flexural and tensile moduli of the composites were significantly enhanced compared with those of pure PLA samples. Dynamic mechanical thermal analysis and thermogravimetric analysis (TGA) results indicate that the loss and storage modulus of PLA/flax fiber composites are increased compared with those of both pure PLA and composites with the coupling agent. The TGA showed that the thermal stability of PLA improved with the addition of flax fiber into PLA. Additionally, the developed flax fiber content in PLA with the coupling agent improved the tensile, flexural strength and flexural modulus. The tensile strength of the alkali-treated flax fiber increased up to 50 MPa compared with that of the untreated flax fiber. The Fourier transform infrared spectroscopy method was carried out to examine the chemical composition of the composite and interaction of functional groups for both alkali-treated and untreated flax fibers.

中文翻译：

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偶联剂和碱处理对亚麻纤维增强聚乳酸复合材料力学、热学和形态学性能的影响

在目前的研究中，三种不同类型的基于聚乳酸 (PLA) 和短亚麻纤维的生物复合材料是通过挤出生产的。为了提高亚麻纤维与PLA基体之间的界面附着力，在挤出工艺前对亚麻纤维进行了碱处理。研究了偶联剂和碱处理对复合材料的影响，包括注射复合材料的机械、热和热机械性能。结果表明，偶联剂对复合材料的热性能、热机械性能和力学性能有良好的影响。与纯PLA样品相比，复合材料的弯曲和拉伸模量显着提高。动态机械热分析和热重分析 (TGA) 结果表明，与纯 PLA 和含有偶联剂的复合材料相比，PLA/亚麻纤维复合材料的损耗和储能模量有所增加。TGA 表明 PLA 的热稳定性随着亚麻纤维加入 PLA 中而提高。此外，在 PLA 中开发的亚麻纤维含量与偶联剂一起提高了拉伸、弯曲强度和弯曲模量。与未经处理的亚麻纤维相比，经过碱处理的亚麻纤维的拉伸强度增加了 50 MPa。进行傅里叶变换红外光谱方法以检查复合材料的化学组成以及碱处理和未处理亚麻纤维的官能团相互作用。