The significant industrial development of non-woven biocomposites requires the implementation of environmentally and economically coherent end-of-life recycling solutions. In this study, we studied the recycling of a non-woven poly-(propylene)-flax composite by injection but also by thermo compression. For comparison, a material with the same architecture but reinforced by glass fibres was studied. Both recycling methods showed strong specificities. Injection recycling leads to efficiently homogenised microstructures of the parts but also to drastically reduced lengths of the fibres, up to 10 times lower than with compression moulding. This method globally promotes high failure strengths while compression moulding, by preserving the length of the fibrous reinforcements, guarantees higher stiffness. This work also highlights the impacts of the length and division of the fibre elements on the microstructure of the injected parts; thus, after a series of compression recycling cycles, injected parts exhibit an important skin-core effect larger than after initial injection recycling cycles, whether in terms of orientation or local fibre volume fraction. As a consequence, after a series of recycling by compression, a new injection cycle has for effect to improve the tensile mechanical performances. For example, the strength and modulus of PP-flax composites are increased by 103% and 75%, respectively. These results highlight the technical feasibility and relevance of implementing these two recycling methods, depending on the volumes or equipment available and the final properties to promote, as they enable the production of new high-performance parts.

非织造生物复合材料的重大工业发展要求实施在环境和经济方面一致的报废回收解决方案。在这项研究中，我们研究了注射成型和热压成型对非织造聚丙烯聚丙烯亚麻复合材料的回收利用。为了进行比较，研究了具有相同结构但由玻璃纤维增​​强的材料。两种回收方法都显示出很强的特异性。注射回收可以有效地使零件的微观结构均匀化，但也可以大大减少纤维长度，比压缩成型的纤维长度低多达10倍。通过保留纤维增强材料的长度，此方法总体上提高了高破坏强度，而压模成型则确保了更高的刚度。这项工作还强调了纤维元素的长度和划分对注射部件的微观结构的影响。因此，在一系列压缩回收循环之后，无论是定向还是局部纤维体积分数，被注射的部件都具有比初始注射再循环循环之后更大的重要的皮芯效应。结果，在通过压缩进行一系列循环之后，新的注射循环有效地改善了拉伸机械性能。例如，PP-亚麻复合材料的强度和模量分别增加了103％和75％。这些结果凸显了实施这两种回收方法的技术可行性和相关性，具体取决于可用的数量或设备以及要推广的最终特性，