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Waste recycling is one of the key aspects in current day studies to boost the country’s circular economy. Recycling wood from construction and demolished structures and combining it with plastics forms wood-polymer composites (WPC) which have a very wide scope of usage. Such recycled composites have very low environmental impact in terms of abiotic potential, global warming potential, and greenhouse potential. Processing of WPCs can be easily done with predetermined strength values that correspond to its end application. Yet, the usage of conventional polymer composite manufacturing techniques such as injection molding and extrusion has very limited scope. Many rheological characterization techniques are being followed to evaluate the influence of formulation and process parameters over the quality of final WPCs. It will be very much interesting to carry out a review on the material formulation of WPCs and additives used. Manufacturing of wood composites can also be made by using bio-based adhesives such as lignin, tannin, and so on. Nuances in complete replacement of synthetic adhesives as bio-based adhesives are also discussed by various researchers which can be done only by complete understanding of formulating factors of bio-based adhesives. Wood composites play a significant role in many non-structural and structural applications such as construction, floorings, windows, and door panels. The current review focuses on the processing of WPCs along with additives such as wood flour and various properties of WPCs such as mechanical, structural, and morphological properties. Applications of wood-based composites in various sectors such as automotive, marine, defense, and structural applications are also highlighted in this review.

Recent era witnessed a tremendous growth in utilization of plant fibers to make composite materials, and their industrial applications have multiplied many folds. All these utilizations were kindled by the advantageous features of the plant fibers and their potential to substitute the currently used synthetic fibers in almost all the applications. Current work falls in line with the abovementioned statements, and Calotropis gigantea fibers (CGFs) are reinforced with epoxy matrix to fabricate composite materials. The fiber surfaces were modified with sodium hydroxide (NaOH) and potassium permanganate (KMnO 4 ) solutions. The CGFs reinforced composites with epoxy matrix were fabricated with the aid of compression molding technique and the samples were subjected to wear tests. The effect of fiber surface modification over the tribological characteristics of these composites such as frictional force, coefficient of friction, and rate of wear was evaluated by varying the time of wear from 40 to 1040 s at an interval of 40 s. From the results, it is found that the weight loss varies between 0.0013 and 0.0018g. Scanning electron microscopy studies are also carried out to observe the surfaces of the samples before and after wear tests. Experimental results portrayed that NaOH treated CGF composites rendered better tribological behavior when compared with untreated and KMnO 4 treated CGF composites.

Additive manufacturing (AM) is a potential engineering technique that could be used in various applications owing to its greatest advantages like flexibility in design, least expensive, versatile material synthesis and low material wastage. From various studies, it was understood that the mechanical performance of fiber-reinforced polymer composite materials (FRPCs) manufactured by AM was influenced by the process parameters to a certain extent. Additionally, numerous studies stated that the strength characteristics of the additively manufactured samples from continuous fibers, like carbon and glass, were high when compared with the samples reinforced with short fibers. Various earlier reviews enunciated that the increase in fiber volume fraction increased the strength and stiffness of the AM components many a times, while the mechanical characteristics of the samples also faced a significant increment due to the addition of fibers. Current work focuses on the influence of process parameters like process of 3D printing, materials used, layer thickness and so on upon the properties of additively manufactured FRPCs. Primary focus of the current study is to determine the effect of factors like thickness of the layer, content of the fiber in volume and the build orientation upon the properties of FRPC components manufactured by AM. This study also outlines the influence of some other parameters like loads applied, environment and analysis models on the properties of AM components along with their merits and demerits.

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