Natural fibers today are a popular choice for applications in composite manufacturing. Based on the sustainability benefits, biofibers such as plant fibers are replacing synthetic fibers in composites. These fibers are used to manufacture several biocomposites. The chemical composition and properties of each of the fibers changes, which demands the detailed comparison of these fibers. The reinforcement potential of natural fibers and their properties have been described in numerous papers. Today, high performance biocomposites are produced from several years of research. Plant fibers, particularly bast and leaf, find applications in automotive industries. While most of the other fibers are explored in lab scales they have not yet found large-scale commercial applications. It is necessary to also consider other fibers such as ones made from seed (coir) and animals (chicken feather) as they are secondary or made from waste products. Few plant fibers such as bast fibers are often reviewed briefly but other p...

A Review of Natural Fibers Used in Biocomposites: Plant, Animal and Regenerated Cellulose Fibers

Over recent years, enthusiasm towards the manufacturing of biopolymers has attracted considerable attention due to the rising concern about depleting resources and worsening pollution. Among the biopolymers available in the world, polylactic acid (PLA) is one of the highest biopolymers produced globally and thus, making it suitable for product commercialisation. Therefore, the effectiveness of natural fibre reinforced PLA composite as an alternative material to substitute the non-renewable petroleum-based materials has been examined by researchers. The type of fibre used in fibre/matrix adhesion is very important because it influences the biocomposites’ mechanical properties. Besides that, an outline of the present circumstance of natural fibre-reinforced PLA 3D printing, as well as its functions in 4D printing for applications of stimuli-responsive polymers were also discussed. This research paper aims to present the development and conducted studies on PLA-based natural fibre bio-composites over the last decade. This work reviews recent PLA-derived bio-composite research related to PLA synthesis and biodegradation, its properties, processes, challenges and prospects.

https://www.mdpi.com/2073-4360/13/8/1326/pdf

Polylactic Acid (PLA) Biocomposite: Processing, Additive Manufacturing and Advanced Applications.

Steam exploded bamboo (SEB) fibers were treated with alkali solution to remove lignin and hemicelluloses and also to increase the compatibility with biodegradable matrix resin. The fibers were processed by simple hand-lay-up method and hot pressed using dispersion-type biodegradable poly lactic acid (PLA) resin to produce a PLA/bamboo fiber cross-ply (0/90) s laminate composites, whose fiber content varied from 17 up to 68 wt.%. The intermolecular interaction among bamboo fiber and PLA matrix was discussed based on Fourier transform infrared (FTIR) analysis. The results showed that the tensile strength of alkali treated bamboo fiber was comparable with those of common strong natural fibers such as hemp and flax fibers. The composites' strength was similar to that of ordinary glass fiber-reinforced plastics laminate and the specific strength was three times higher than that of mild steel. It was also found that the cross-ply (0/90) s SEB/PLA laminate has the same cracking character as the common cross-ply laminates based on carbon or glass fibers.

Strength evaluation of cross-ply green composite laminates reinforced by bamboo fiber

Effect of lumen size on the effective transverse thermal conductivity of unidirectional natural fiber composites

To study the effect of the microstructure of natural fiber on the transverse thermal conductivity of unidirectional composite, abaca and bamboo fibers were unidirectionally aligned to fabricate epoxy composites by a resin transfer molding (RTM) technique. The transverse thermal conductivity of these two types of composites was measured in a steady-state platform. X-ray diffractometer and scanning electron microscopy were applied to analyze the microstructure and morphology of both fibers and composites. The results indicated that the transverse thermal conductivity showed two types of tendencies with fiber content increasing: increasing for bamboo fiber composites, and decreasing for abaca fiber composites. The microstructure and theoretical analysis suggest that the lumen structure plays a great role rather than crystal structures and chemical compounds on the transverse thermal conductivity of unidirectional composites, which is useful for further development and design of natural fiber reinforced composites with better thermal insulation property for people’s daily life.

Effect of physicochemical structure of natural fiber on transverse thermal conductivity of unidirectional abaca/bamboo fiber composites

'Green' composites were fabricated from poly lactic acid (PLA) and bamboo fibers by using a conventional hot pressing method. The insulating properties of the PLA-bamboo fiber 'green' composites were evaluated by determination of the thermal conductivity, which was measured using a hot-wire method. The thermal conductivity values were compared with theoretical estimations. It was demonstrated that thermal conductivity of PLA-bamboo fiber 'green' composites is smaller than that of conventional composites, such as glass fiber reinforced plastics (GFRPs) and carbon fiber reinforced plastics (CFRPs). The thermal conductivity of PLA-bamboo fiber 'green' composites was significantly influenced by their density, and was in fair agreement with theoretical predictions based on Russell's model. The PLA-bamboo fiber composites have low thermal conductivity comparable with that of woods.

Shuhei Kako

Papers

Thermal conductivity of PLA-bamboo fiber composites