Additive manufacturing of polypropylene micro and nano composites through fused filament fabrication for automotive repair applications

Abstract

The emerging Additive manufacturing technologies are being adopted by different industries, which require developing new materials and procedures. Here we report the development of polypropylene (PP) based composite materials for fused filament fabrication (FFF) process with the aim of enabling fully automatic robotic repair application of plastic components in automotive industry. A key challenge in repair and joining of polyolefins, which are widely used in such applications, is understanding the interplay of microstructural features and the joining mechanisms employed to achieve a uniform and fully functional repaired components. Specifically, for components manufactured from polypropylene based material, we show that the addition of ethylene propylene diene monomer (EPDM), polyisobutylene (PIB) and carbon black (CB) successfully modifies its matrix and produces a composite material ideal for additively repairing of complex geometries found in the automotive applications.This was brought about by effective reduction of the crystallinity of the composite PP matrix from 46.2% to 34.4% and resulting in a net reduction in warpage of the FFF 3D printed samples. Further, the thermal stability of the developed composite was improved with the addition of a moderate amount of carbon filler, enabling an FFF process with higher hot-end temperatures, which subsequently allowed for tuning of the raw material's viscosity, and hence ensuring consistent deposition of molten filaments for building successive layers. Mechanical properties' analysis revealed that the addition of 10 wt.% CB increased the true stiffness (storage modulus) by 20%, the impact strength by 62%, with the drop in ultimate tensile strength of 11%.The optimal elongation at break and toughness were achieved for the samples containing 2 wt.% CB increasing these key properties by 62% and 58%, respectively. In terms of the melt flow index (MFI), as a key rheological indicator, the measured value ranged between 12.5 and 19.0 g=10 min for all compositions suitable for the FFF process. Morphological analysis of the extruded filaments and fracture surface of impact test samples showed a mesoscale interspersion of polymer phases and a

Mechanical properties of additively manufactured polymeric composites using sheet lamination technique and fused deposition modeling: A review

“…It could print non‐periodic 3‐D geometry, large‐scale contiguous parts, multiple smaller distinct parts, or a combination of both with different shapes and sizes on the same machine. Jahromi et al 145 created PP‐based composites with carbon black (CB), ethylene propylene diene monomer (EPDM), and polyisobutylene (PIB), resulting in composite materials that are ideal for additively repairing complex geometries in the automotive industry. The results indicated that the infusion of 10 wt% CB improved the impact strength and storage modulus by 62% and 20%, respectively.…”

Polymeric composites in extrusion‐based additive manufacturing: a systematic review

“…It has been compounded with ceramics, 67,86 natural reinforcements, 98,162 glass fiber, 131,148,149 carbon fiber, 163 and carbon black. 176 On the other hand, PETG has been more frequently reinforced with carbonaceous components 95,104,110,124,131,132,177 and has composed the first successful introduction of metal alloy micro-fibers in additive manufacturing of thermoplastics. 112 With more restricted publication numbers, composites based on high-density polyethylene (HDPE) and polycarbonate (PC) have been explored with ceramic reinforcements 69,77,86,96,160 and carbon fiber, 147 while thermoplastic polyurethane (TPU) has usually been associated with investigations in which flexibility is desired, including the development of electrically conductive composites, 175 the applicability in piezoresistive sensors, 129 and the design of humidity-responsive structures.…”

“…84,87 In the former case, filler weight fractions up to 10% reduced the intrinsic warpage of the polymeric matrix and increased the storage modulus and impact strength of the printed specimens. 176 On the other hand, the latter scenario was primarily concerned with exploring electrical conductivity. From a commercial filament, Tirado-Garcia et al 84 reported a strong influence of printing direction on the thermal, electrical, and mechanical properties of 3D printed PLA/carbon black composites.…”

Applications of plastics in the automotive industry: Current trends and future perspectives

“…The advent of pioneering technologies, such as additive manufacturing and advanced composite materials, is revolutionizing the capabilities of plastics in terms of their structural robustness, operational effectiveness, and overall performance. [25][26][27] This review paper examines the myriad applications of plastics in the automotive industry, exploring current trends and discussing future perspectives. This paper examines the impact of plastics on automobile design, material advancements, sustainability initiatives, and associated challenges within the automotive industry.…”

“…In this milieu, a significant surge in the application of plastics in automobiles is expected. The advent of pioneering technologies, such as additive manufacturing and advanced composite materials, is revolutionizing the capabilities of plastics in terms of their structural robustness, operational effectiveness, and overall performance 25–27 . This review paper examines the myriad applications of plastics in the automotive industry, exploring current trends and discussing future perspectives.…”