In this review, insight into the use of bio-based fibers as composite reinforcement has been addressed. Specifics on the varieties of natural fibers, and the resultant properties from their constituents and hierarchal structures are described. The methods used to enhance the interface of these fibers with a variety of polymer matrices are reviewed. In addition, the influence of textile operations on creating various fiber architectures with resulting reinforcing capabilities, along with the methods in which natural fiber reinforced composites can be processed, are addressed. Finally, discussion of the correlation between structure, processing, and final composite properties are provided.

Natural Fiber Reinforced Composites

Environmental friendly method for the extraction of coir fibre and isolation of nanofibre.

Natural fiber reinforced polymer composites play important roles in the production of eco-friendly materials because of their high modulus, meticulous strength and reduced carbon footprint on the environment. Coconut (cocos nucifera) is cultivated extensively in tropical countries for its fruits whereas the husks and shells are mostly disposed as waste. These portions of the coconut plant serve as potential resource for natural fibers which are used to reinforce polymer composites. This work gives an overview of current knowledge of coir fiber and coir fiber reinforced polymer composites. The preparation and production of different matrices reinforced with coir fibers and the mechanical structural and thermal properties of these composites have been studied by several researchers and are elucidated in this review. The major treatment techniques used to modify coir fibers were also discussed.

A review of coir fiber reinforced polymer composites

The objective of this paper is to review the published literature on improving properties of wood composites through thermal pretreatment of wood. Thermal pretreatment has been conducted in moist environments using hot water or steam at temperatures up to 180 and 230 °C, respectively, or in dry environments using inert gases at temperatures up to 240 °C. In these conditions, hemicelluloses are removed, crystallinity index of cellulose is increased, and cellulose degree of polymerization is reduced, while lignin is not considerably affected. Thermally modified wood has been used to manufacture wood–plastic composites, particleboard, oriented strand board, binderless panels, fiberboard, waferboard, and flakeboard. Thermal pretreatment considerably reduced water absorption and thickness swelling of wood composites, which has been attributed mainly to the removal of hemicelluloses. Mechanical properties have been increased or sometimes reduced, depending on the product and the conditions of the pretreatment. Thermal pretreatment has also shown to improve the resistance of composites to decay.

/pdf/a-review-of-wood-thermal-pretreatments-to-improve-wood-1pjb9cb6gu.pdf

A review of wood thermal pretreatments to improve wood composite properties

Influence of pretreated activated sludge for electricity generation in microbial fuel cell application.

In this study, physical, mechanical, and flammability properties of coconut fiber reinforced polypropylene (PP) composite panels were evaluated. Four levels of the coir fiber content (40, 50, 60, and 70 % based on the composition by weight) were mixed with the PP powder and a coupling agent, 3 wt % maleic anhydride grafted PP (MAPP) powder. The water resistance and the internal bond strength of the composites were negatively influenced by increasing coir fiber content. However, the flexural strength, the tensile strength, and the hardness of the composites improved with increasing the coir fiber content up to 60 wt %. The flame retardancy of the composites improved with increasing coir fiber content. The results suggest that an optimal composite panel formulation for automotive interior applications is a mixture of 60 wt % coir fiber, 37 wt % PP powder, and 3 wt % MAPP.

https://www.fpl.fs.fed.us/documnts/pdf2011/fpl_2011_ayrilmis002.pdf

Coir fiber reinforced polypropylene composite panel for automotive interior applications

Effect of thermal-treatment of wood fibres on properties of flat-pressed wood plastic composites

Overlaying properties of fiberboard manufactured from bamboo and rice straw

This study investigated some of the important properties of single-layer particleboard panels made from bamboo (Dendrocalamus asper), rice straw, eucalyptus (Eucalyptus camaldulensis), or combinations of them A total of 40 experimental panels were manufactured from each material type Panels were also made using a 50:50 ratio of eucalyptus and bamboo, eucalyptus and rice straw, and bamboo and rice straw; a 50:25:25 ratio of eucalyptus, rice straw, and bamboo; and a 70:15:15 ratio of eucalyptus, rice straw, and bamboo, respectively Average target density of the panels ranged from 075 to 078 g/cm 3  Modulus of rupture, modulus of elasticity, internal bond strength, thickness swelling, water absorption, density profiles, and surface roughness of the specimens were determined Panels with 50:50 bamboo and eucalyptus particles resulted in the highest mechanical properties followed by panels made from 100 percent bamboo Boards manufactured with 100 percent rice straw produced the lowest properties The amount of rice straw in the panels significantly reduced both physical and mechanical properties of the samples The overall panel properties improved as lower percentage of rice straw were added to the mats Based on initial results of this study, three under-utilized species can be used to manufacture value-added particleboard panels It also appears that an addition of rice straw into the mats should be less than 15 percent to achieve better panel properties

Properties of bamboo-rice straw-eucalyptus composite panels

This study evaluated some of the important properties of medium density fiberboard (MDF) panels made from bamboo (Dendrocalamus asper) and rice straw. A total of 20 experimental panels with an average target density of 0.70 g/cm 3 were made from 100 percent bamboo, 100 percent rice straw and the mixture of 80 to 20 percent and 50 to 50 percent ratios of bamboo and rice straw fiber. Modulus of elasticity (MOE), modulus of rupture (MOR), internal bond strength, thickness swelling, density profiles, and surface roughness of the specimens were determined. Samples with 0.75 g/cm 3 density had 34 percent and 27 percent higher MOE and MOR values than those of samples with target density of 0.65 g/cm 3 , respectively. It appears that using 5 percent of rice straw in the panels did not significantly reduce both physical and mechanical properties of the samples. Measurement of surface characteristics of the samples resulted that such panels can be used as substrate for thin overlays without any significant problems. Initial findings of this study suggest that both nonwood underutilized species can be considered as raw material to manufacture value-added MDF panels.

Piyawade Bauchongkol

Papers

Coir fiber reinforced polypropylene composite panel for automotive interior applications

Effect of thermal-treatment of wood fibres on properties of flat-pressed wood plastic composites

Overlaying properties of fiberboard manufactured from bamboo and rice straw

Properties of bamboo-rice straw-eucalyptus composite panels

Selected properties of medium density fiberboard (MDF) panels made from bamboo and rice straw