Biocomposites made from renewable resources have a lower environmental impact than inorganic composites. However, these new biocomposites must have the same mechanical properties as traditional composites to be able to replace them. The main objective of this study is to analyze the influence of strain rate and fiber content on the mechanical behavior of a new biocomposite composed of a biodegradable PolyHydroxyAlkanoate (PHA) matrix reinforced by Alfa fibers. These biocomposites were elaborated after an alkaline treatment and fiber bleaching procedure. SEM and chemical analysis showed that these treatments remove the non-cellulosic materials such as pectin, hemicellulose and lignin, and improve the cellulose content. Three fiber contents of 5, 10 and 15%wt and three strain rates were investigated to analyze their dependence on uniaxial tensile tests. By increasing the amount of fiber and the strain rate, the mechanical response was improved with higher Young’s modulus and tensile strength but lower elongation at break. Poisson’s ratio have also shown dependence on strain rate and fiber contents. These results underline the good mechanical properties of this PHA/Alfa biocomposite which could be an interesting alternative in the development of products, such as automotive interior parts or some packaging applications.

中文翻译：

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Alfa 纤维增强聚羟基脂肪酸酯的机械特性：纤维含量和应变率的影响

由可再生资源制成的生物复合材料比无机复合材料对环境的影响更低。然而，这些新型生物复合材料必须具有与传统复合材料相同的机械性能才能取代它们。本研究的主要目的是分析应变率和纤维含量对由阿尔法纤维增强的可生物降解聚羟基链烷酸酯（PHA）基质组成的新型生物复合材料机械行为的影响。这些生物复合材料是经过碱处理和纤维漂白程序后精心制作的。SEM和化学分析表明，这些处理去除了果胶、半纤维素和木质素等非纤维素材料，并提高了纤维素含量。研究了 5%、10% 和 15%wt 三种纤维含量和三种应变率，以分析它们对单轴拉伸试验的依赖性。通过增加纤维量和应变率，机械响应得到改善，杨氏模量和拉伸强度更高，但断裂伸长率更低。泊松比还显示出对应变率和纤维含量的依赖性。这些结果强调了这种 PHA/Alfa 生物复合材料的良好机械性能，这可能是汽车内饰件或某些包装应用等产品开发中的一个有趣的替代方案。