Mechanical, Thermal and Microstructural Characteristic of 3D Printed Polylactide Composites with Natural Fibers: Wood, Bamboo and Cork

Abstract

In the study, polylactide-based (PLA) composites modified with natural particles (wood, bamboo, and cork) and with different levels of infilling (100%, 80%, and 60%) obtained by fused deposition modeling were tested. The effect of fiber type, infill level and crystallization rate on the mechanical properties were investigated by using tensile, flexural, and impact tests. The materials were subjected to mechanical tests carried out at 23 and 80 °C. Differential scanning calorimetry were employed to analyze crystallization behavior of composite. Furthermore, hydrothermal degradation was performed, and its effect on the properties was analyzed. The addition of natural fillers and different levels of infilling result in a similar level of reduction in the properties. However, the addition of natural fillers resulted in a slightly lower drop than the lowered infilling rate − 40% and 50% for tensile strength, respectively. Moreover, it was found that, composites made of PLA are more sensitive to high temperatures than to water. The decrease in Young's modulus of PLA at 80 °C was 90%, while after 28 days of hydrodegradation ~ 9%. The addition of fibers reduced this decrease at elevated temperatures. Importantly, in the case of a brittle material such as PLA, the impact strength has been improved by 50% for composites with cork particles and other lignocellulosic composites remained at the same level as for resin. Generally, the thermal treatment of composites increased the degree of crystallinity of the materials, as reflected in the higher results of mechanical tests.

Physical, Mechanical, and Thermal Properties and Characterization of Natural Fiber Composites Reinforced Poly(Lactic Acid): Miswak (Salvadora Persica L.) Fibers

“…As shown in (Figures 7(a)-7(c)), the increase in porosity of the composites brought on by insufficient interfacial bonding is what leads to the drop in characteristics. The outcomes match those of the PLA composite with natural fibers work as determined by SEM [49]. Yusoff et al [62] found that while the flexural strength of kenaf-coir/ PLA was lower than kenaf-bamboo-coir/PLA and bamboocoir/PLA, it had the highest flexural modulus, which was 70% higher than the other combinations, as the impurities in bamboo fiber caused fiber-matrix interfacial failure and decreased the stiffness of the composites [62].…”

“…However, as shown by SEM in Figures 7(b) and 7(c), the condition of poor adhesion between the fiber and the matrix had led to a reduction in tensile characteristics. According to study made by Mazur et al, PLA composites made with natural particles (Wood, Bamboo, and Cork), inadequate fiber/matrix adhesion, and empty spaces in the material had a detrimental impact on the material's mechanical characteristics [49]. Pongtanayut et al discovered that the insertion of soft phase rubber reduced the tensile strength of PLA matrix, suppressing PLA crystallinity and resulting in decreased tensile strength [50].…”

“…Fiber orientation is another aspect that impacts the flexural characteristics. As the fiber orientation becomes more parallel to the direction of the load applied, the greater the flexural qualities since the phenomena happening during the flexural test depend on the location, with the top layer being subjected to compression and the lower layer to tension [49]. However, Golmakani et al [61] discovered the opposite conclusion in their investigation into the impact of wood powder and nanoclay particle content on polyethylene matrix.…”

Thermal characterization and hygrothermal aging of lignocellulosic Agave Cantala fiber reinforced polylactide composites

“…They established accurate crystal structure and the measurements taken between 25 and 150 C. The merits of polylactide are higher stiffness to strength ratio, biocompatibility, processability, and also its hydrophobic nature. [12] Polylactide are extensively employed in fused deposition modeling (3D printing) technique and used for aerospace, food packaging, pharmaceutical and biomedical applications. [13,14] The need for a biodegradable alternative material for engineering structures has prompted researchers to look at the utilization of natural resources as a part of advanced materials with the objective of reducing the use of steel, plastics in different structures.…”

“…The merits of polylactide are higher stiffness to strength ratio, biocompatibility, processability, and also its hydrophobic nature. [ 12 ] Polylactide are extensively employed in fused deposition modeling (3D printing) technique and used for aerospace, food packaging, pharmaceutical and biomedical applications. [ 13,14 ]…”