With the objective of giving a new economic life to postindustrial waste poly(lactic acid) (PLA), biocomposites based on recycled PLA were manufactured using conventional melt blending, and the strands produced were successfully used for three-dimensional (3D) printing of American Society for Testing and Materials (ASTM) samples by means of the fused deposition molding (FDM) method. This article further discusses the processing advantages and challenges associated with void formation, anisotropic behavior, and the quality of the 3D printed (3DP) samples in comparison with injection-molded (IM) counterparts. The blends were manufactured containing 30 wt % of recycled PLA in a matrix of virgin PLA. Similarly, blends were also prepared with addition of an epoxy-based chain extender (CE) and as well as with the CE and a reinforcing phase of microcrystalline cellulose (MCC). One of the limitations of recycled PLA in FDM-based 3D printing is its high melt flow due to the reduced molecular weight after recycling, which results in excessive material flow during extrusion, and hence limits its application in FDM-based 3D printing. Consequently, the main effect of the CE, Joncryl, was to control the Melt Flow Index (MFI) of the biocomposites containing the recycled PLA. The addition of CE also resulted in improvement of the impact strength of 3DP samples. In general, the CE in combination with the natural fibers (MCC) allowed the incorporation of postindustrial PLA. Data suggest that more recycled PLA may be incorporated by using this blend combination. In general, owing to the void formation, 3DP samples presented lower values of density (lightweight) and mechanical properties as compared with IM samples. However, the tensile strength, modulus and Izod impact strength of 3DP biocomposites were increased by up to 88%, 127%, and 11%, respectively, by the addition of 5 wt % MCC, as compared with 3DP samples based on postindustrial PLA without additives.

为了给后工业废聚乳酸（PLA）提供新的经济寿命，使用常规熔体共混技术制造了基于回收PLA的生物复合材料，并将生产的线成功用于美国的三维（3D）打印美国材料试验学会（ASTM）的样品采用熔融沉积成型（FDM）方法。本文将进一步讨论与注塑成型（IM）相比，与空洞形成，各向异性行为以及3D打印（3DP）样品质量相关的加工优势和挑战。所制造的共混物在原始PLA基质中包含30wt％的再循环PLA。同样，还通过添加环氧基扩链剂（CE）以及CE和微晶纤维素的增强相（MCC）来制备共混物。在基于FDM的3D打印中回收的PLA的局限性之一是其高熔体流动性，这归因于回收后分子量的降低，这导致挤出过程中材料流动过多，从而限制了其在基于FDM的3D打印中的应用。因此，CE Joncryl的主要作用是控制含有回收的PLA的生物复合材料的熔体流动指数（MFI）。CE的添加还提高了3DP样品的冲击强度。通常，将CE与天然纤维（MCC）结合使用，可掺入工业后PLA。数据表明，通过使用这种共混物，可以回收更多的回收PLA。通常，由于形成空隙，与IM样品相比，3DP样品的密度（轻量）和机械性能值较低。但是，与不使用工业后PLA的3DP样品相比，通过添加5 wt％的MCC，3DP生物复合材料的拉伸强度，模量和悬臂梁式冲击强度分别提高了88％，127％和11％。添加剂。