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 plant and animal fibers are not discussed in detail. This review paper discusses all the six types of plant fibers such as bast, leaf, seed, straw, grass, and wood, together with animal fibers and regenerated cellulose fibers. Additionally, the review considers developments dealing with natural fibers and their composites. The fiber source, extraction, availability, type, composition, and mechanical properties are discussed. The advantages and disadvantages of using each biofiber are discussed. Three fabric architectures such as nonwoven, woven and knitted have been briefly discussed. Finally, the paper presents the overview of the results from the composites made from each fiber with suitable references for in-depth studies.

Natural fiber composites are known to absorb more water than glass fiber reinforced composites. In this study, hybrid natural fiber composites were prepared by combining different fiber reinforcements, and both the water absorption and the mechanical properties were studied. Compression molding technique was used to manufacture composite laminates from a bio-based resin (acrylated epoxidized soybean oil) and natural fibers: non-woven and woven jute, non-woven regenerated cellulose mat (Lyocell and viscose), and woven glass fiber. The composite laminates were cured at 160–170°C and 40 bar, with a fiber content of 40 wt%. We investigated effect of pretreatment of regenerated cellulose fiber using 4% NaOH solution. The gravimetric water absorption was tested by exposure to water for 10 days. Specimens were cut from composites with laser-cutting technique according to ISO standards, and tested for tensile, flexural, and impact strength. To determine the influence of water absorption on the mechanical properties, specimens were immersed in distilled water for 10 days before testing. As a reference, dry specimens were tested. The results showed that water absorption was reduced by producing hybrid composites with jute fibers, glass fiber, and Lyocell fiber. The tensile, flexural, and impact properties were improved by inclusion of glass fiber and Lyocell in the composite. The tensile and flexural properties of natural fiber reinforced composites were mostly affected by the influence of water, but this was improved considerably by hybridization with glass and Lyocell fibers. The viscoelastic properties of the manufactured composites and hybrid composites were studied using dynamic mechanical thermal analysis.