On the Strain Rate Sensitivity of Fused Filament Fabrication (FFF) Processed PLA, ABS, PETG, PA6, and PP Thermoplastic Polymers

Abstract

In this study, the strain rate sensitivity of five different thermoplastic polymers processed via Fused Filament Fabrication (FFF) Additive Manufacturing (AM) is reported. Namely, Polylactic Acid (PLA), Acrylonitrile-Butadiene-Styrene (ABS), Polyethylene Terephthalate Glycol (PETG), Polyamide 6 (PA6), and Polypropylene (PP) were thoroughly investigated under static tensile loading conditions at different strain rates. Strain rates have been selected representing the most common applications of polymeric materials manufactured by Three-Dimensional (3D) Printing. Each polymer was exposed to five different strain rates in order to elucidate the dependency and sensitivity of the tensile properties, i.e., stiffness, strength, and toughness on the applied strain rate. Scanning Electron Microscopy (SEM) was employed to investigate the 3D printed samples’ fractured surfaces, as a means to derive important information regarding the fracture process, the type of fracture (brittle or ductile), as well as correlate the fractured surface characteristics with the mechanical response under certain strain rate conditions. An Expectation–Maximization (EM) analysis was carried out. Finally, a comparison is presented calculating the strain rate sensitivity index “m” and toughness of all materials at the different applied strain rates.

Sustainable Additive Manufacturing: Mechanical Response of Polyamide 12 over Multiple Recycling Processes

“…From these micro-cracks and while the material is being stressed at an external quasi static tensile field, it can be envisaged that some cracks could initiate and propagate in the longitudinal direction that the tensile test stress field is applied, resulting into a "plasticization"-like effect and yielding further to generally lower tensile modulus of elasticity values or, in other words, a knock-down effect on the material's modulus. Specifically, similar behavior has been also observed for ABS, PLA, HDPE and PP as reported in our previous recent study [37], corroborating the behavior that was also experimentally determined for PA12 tensile modulus of elasticity values in the study at hand.…”

Effects of Coagent Functionalities on Properties of Ultrafine Fully Vulcanized Powdered Natural Rubber Prepared as Toughening Filler in Rigid PVC

“…The results showed that PVC loaded with UFPNR had a rougher surface fracture than that of neat PVC. This implied that neat PVC had a brittle fracture mechanism [33]. With the addition of UFPNR content of up to 8 phr, a ductile fracture mechanism could be observed in the fracture surface of PVC, which was spanned by some drawn elongated fibrils.…”

Enhanced Mechanical, Thermal and Antimicrobial Properties of Additively Manufactured Polylactic Acid with Optimized Nano Silica Content

“…This potential of AM process in combination with bio-based materials, such as the PLA, creates a research need for the development of advanced composite materials. PLA has been thoroughly studied and it is continually under development with a large variety of fillers [2,8,21] and applications related to 3D printing for the development of composites with antimicrobial properties [22]. Polylactide is a famous polymer used in 3D printing, with an "easy-to-print" behavior.…”