Mechanical properties and surface quality of natural rubber-poly (Lactic Acid) composites for fused deposition modelling technology

Alias, Amirah Maisarah (2022) Mechanical properties and surface quality of natural rubber-poly (Lactic Acid) composites for fused deposition modelling technology. Project Report. Melaka, Malaysia, Universiti Teknikal Malaysia Melaka. (Submitted)

	Text (24 Pages) Mechanical properties and surface quality of natural rubber-poly (Lactic Acid) composites for fused deposition modelling technology.pdf - Submitted Version Download (371kB)
	Text (Full Text) Mechanical properties and surface quality of natural rubber-poly (Lactic Acid) composites for fused deposition modelling technology.pdf - Submitted Version Restricted to Repository staff only Download (4MB)

Abstract

Additive Manufacturing (AM) technology builds parts layer by layer through the deposition of liquidized material according to digital 3D design data. Fused Deposition Modelling (FDM) has been the most prevalent in 3D printing technology. Poly (lactic acid) or PLA, is one of the thermoplastic polymers in 3D printing that is biodegradable and has potential for biomedical applications. The only drawback is that the PLA is brittle, has low toughness, and inflexibility in its pure form. Due to this, many efforts have been undertaken to develop effective additives for PLA modification in order to expand application possibilities. Therefore, the correct blending ratio of the polymer and additives needs to be identified. In this study, the compatibility of NR and PLA-based blends were investigated for filament fabrication in FDM technology through mechanical properties analysis. Initially, the blends were prepared according to NR/PLA ratios of 10/90, 20/80, 30/70, 40/60, 50/50, 60/40, 70/30, and 90/10, and melt compounding with an internal mixer. Subsequently, the mechanical properties of NR-reinforced PLA specimens fabricated via a hot-pressed machine were compared with the pure PLA for tensile and flexural strength. The compound of fabricated specimens was moulded using a hot-press compression method that conforms with the ASTM-D638 (Type IV) and ASTM-D790, tested using the Shimadzu Universal Testing Machine (UTM) at the speed of 5 mm/minute and 50 mm/minute, respectively. A Mitutoyo Surftest SJ-301 profilometer was used to examine the surface quality (Ra) of the NR-reinforced PLA specimens compared to the pure PLA specimen fabricated via 3D printing. The cross-sectional of the fractured tensile specimen was used for microstructure analysis to study the blending mechanism of the NR/PLA. The result of this study shows that the 40 phr NR/PLA composition enhances the tensile and flexural strength compared to the pure PLA. However, the 20 phr NR/PLA offers a better Ra value for the hot-pressed specimen. Other than that, the SEM images indicated that the size of NR droplets increases with decreasing rubber content. In conclusion, a blending ratio of NR40/PLA60 was found to be the best for FDM filament fabrication in future work since the mechanical properties are more detrimental than the surface roughness in this judgement. As a recommendation, a further analysis of the NR/PLA composites shall be conducted for DSC, FTIR, hardness test, impact test, water absorption test, or XRD to further analyze the properties of these NR/PLA composites. This is important with consideration of the cost of PLA pellets, in addition to the time needed for the preparation of a sufficient amount of NR/PLA blends before NR/PLA filament could be manufactured via a single screw extruder.

Actions (login required)

View Item