Enhanced mechanical properties of plasticized polylactic acid filament for fused deposition modelling: Effect of in situ heat treatment

Abstract

The objective of this study is to characterize the effect of in situ heat treatment on polylactic acid (PLA) and plasticized PLA during fused deposition modelling (FDM) with the motivation to improve their mechanical, thermal and physical properties. The in situ heat treatment was formed during the FDM by adjusting the bed temperature to 70°C, 90°C and 120°C. The performance of 3D, the printed samples, was compared with the compression moulded samples treated at the same temperature using a vacuum oven. PLA was plasticized with poly (ethylene glycol) (PEG) at different compositions of 0, 5 and 10 wt% of PEG. The properties of PLA, plasticized PLA and FDM-printed sample were analysed using Instron, differential scanning calorimeter (DSC) and X-ray diffraction (XRD). It was found that the addition of PEG into PLA decreased the tensile strength, elongation at break and tensile modulus of the materials. However, after heat treatment in the vacuum oven and FDM, the properties were generally higher at 90°C and this was believed to be primarily due to the effect of crystallization. This can be proved by formation of double melting peak, correspond to melt-crystallization mechanism, observed in DSC. The formation of different crystal was supported by XRD analysis where the amorphous peak had transformed into sharp peak at 16.9° and 19.3°, which indicates an improved crystallinity. Comparison between the compression moulded sample and FDM demonstrated that the in situ heat treatment in FDM had the most significant impact on tensile modulus.

On Comparison of Heat Treated and Non-Heat-Treated LOM Manufactured Sample for Poly(lactic)acid: Mechanical and Morphological View Point

“…The results of the study have suggested a 60% improvement in the surface roughness value whereas, the mechanical strength was not explored. Many studies in the past 5 years have been performed dealing with the in-situ treatment or post-treatment of FDM-printed specimens such as using pressure [ 26 ], cold vapor post-processing [ 27 ], and in-situ heat treatment while FDM printing of PLA specimens [ 28 ]. The increased in-situ pressure while FDM printing has tremendously improved mechanical properties by 100 to 150% for PLA samples [ 26 ].…”

“…The increased in-situ pressure while FDM printing has tremendously improved mechanical properties by 100 to 150% for PLA samples [ 26 ]. The in-situ heat treatment of PLA samples [ 28 ] was compared to heat treated sample of a vacuum oven. The results have proved that vacuum oven-based heat treatment improved mechanical strength (tensile strength 90 MPa) better than in-situ treatment (35 MPa).…”

Experimental investigation and optimization of printing parameters of3Dprinted polyphenylene sulfide through response surface methodology

“…Contrariwise, annealing at high temperature (up to PPS's glass transition) would generate an isothermal crystallization which provides enough energy to molecular chains to have the best arrangement to form more crystalline regions and uniform lamellae. [41,57] In this work, the choice of annealing temperatures at 180, 200, and 220 C was based on this latter theory.…”

Physical, thermal and tensile behaviour of 3D printed kenaf/PLA to suggest its usability for ankle–foot orthosis – a preliminary study

“…The main reason for exploring natural composite materials in the orthotics field is that these materials are mostly biodegradable, renewable, have low densities and most importantly, low production cost compared to synthetic materials, which are highly recommended for temporary applications such as an orthosis. Previous research has shown that filaments’ durability and strength using natural materials as reinforcement can be enhanced, especially when paired with PLA as the filament’s matrix (Rafie et al , 2020).…”