Fundamental investigation of potentially recyclable intrinsic polymer fiber-reinforced plastics for local component strengthening by 3D printing using fused filament fabrication FFF

对于许多应用，纯塑料的结构性能是不够的。为了改善这些性能，聚合物因此经典地用纤维增强。然而，这些通常也会导致更高的密度，并且也限制了机械回收的潜力，因为增强效果取决于纤维长度，并且这些长度在螺杆机中的机械回收期间不可避免地缩短。这就是微纤维复合材料（MFC）的用武之地。它们是根据M的想法制造的。Evstatiev和S. Fakirov（Polymer 1992，33，877）和联合收割机将纤维形状的承载优势与塑料的低密度相结合。在以前的工作中，很明显，聚合物纤维在注塑成型的成型部件生产的增强效果不能充分利用，因为这个过程中产生的纤维在体积的随机取向。本项目建议的基本思想是更好地利用MFC的优点，使用熔融长丝制造（FFF），以平面三维轮廓结构。初步研究表明，MFC可以显著提高刚度和强度，并且可以在不损失机械性能的情况下多次通过螺杆机，即具有潜在的机械可回收性。在该项目中，FFF/MFC组合的潜力将被系统地和弹性地研究。拟议项目的总体目标是通过将MFC和FFF联系起来，并深入了解工艺，形态和机械性能之间的关系，为高性能和可回收产品开辟一条道路，作为传统非连续长纤维增强塑料的补充。具体而言，目标是：（1）专门利用塑料组件中定向不连续长纤维聚合物增强的正交各向异性特性，（2）以基于模拟和形态学相关的方式研究和评估打印参数对所得组件特性的影响，（3）研究相容剂对原纤形成和原纤-基质粘附的影响，以及（4）评估材料/工艺组合在组件设计和可回收性方面的适用性。

For many applications, the structural properties of neat plastics are insufficient. To improve these properties, polymers are therefore classically reinforced with fibers. However, these usually also result in a higher density and also limit the potential for mechanical recycling, since the reinforcing effect depends on the fiber length and these are inevitably shortened during mechanical recycling in screw machines. This is where microfibrillar composites (MFCs) come in. They are manufactured according to an idea by M. Evstatiev and S. Fakirov (Polymer 1992, 33, 877) and combine the load-bearing advantages of the fiber shape with the low density of plastics. In previous work, it became clear that the reinforcing effect of polymeric fibers in molded part production by injection molding cannot fully exploit since this process generates randomized orientation of the fibers in the volume.The fundamental idea of the present project proposal is to better exploit the advantages of MFC using Fused Filament Fabrication (FFF) with a view to planar 3D contoured structures. Preliminary investigations demonstrates that significant increases in stiffness and strength are possible with MFC and that a multiple pass through a screw machine can be tolerated without losses in the mechanical properties, i.e. mechanical recyclability is potentially available.In the project, the potentials of the FFF/MFC combination are to be systematically and resiliently researched. The overall goal of the proposed project is to open a pathway to high performance and recyclable products as a complement to conventional discontinuous long fiber reinforced plastics by linking MFC and FFF and developing a deep understanding of the relationships between process, morphology and mechanical properties. Specifically, the objectives are:(1) to specifically exploit the orthotropy properties of directional discontinuous long fiber polymer reinforcement in plastic components,(2) to investigate and evaluate the effect of the printing parameter on the resulting component properties in a simulation-based and morphology-related manner,(3) to investigate the influence of compatibilizers on fibril formation and fibril-matrix adhesion, and(4) to evaluate the suitability of the material/process combination in terms of component design and recyclability.