Valorisation of Agricultural Wastes to Biocomposite Materials for Industrial Application: A Review

Abstract

In recent years, the market has seen a gradual movement towards a circular economy model that uses materials efficiently, minimises waste and focuses on reuse and recycling, which has contributed to the emergence of interest in finding sustainable alternatives to traditional synthetic materials made from petroleum. This review attributes evidence on the viability and sustainability of hybrid bio-composite materials from agricultural wastes as an alternative to synthetic materials. Along with this, valorisation of these easily obtainable, cheap by-products like rice husk, sugarcane bagasse, coconut coir, etc., as reinforcement fibres embedded in a polymer matrix is highlighted. The review highlighted the latest knowledge regarding the chemical composition of natural fibres, surface modification methods for enhancing the fibre-matrix compatibility and selection of polymer matrices (thermosets and thermoplastics). In addition, the sound-absorbing characteristics of these biocomposites are extensively discussed, with particular focus on their porous structure and ability to absorb sound energy, which is crucial for their use in various applications, including the automotive and construction industries. Also, the review encompassed the formulation techniques, characterisation (physical, mechanical, acoustic and thermal) and new industrial applications in automotive, construction, furniture and packaging industries. A total of 100 journal papers and conference proceedings were sourced from Science Direct, Research Gate, Google Scholar, and Semantic Scholar, mostly published between 2021 and 2025, were reviewed using the inclusion/exclusion criteria method. This study included peer-reviewed journal articles, conference proceedings, review papers, and technical publications that reported pertinent experimental results. For this purpose, publications were excluded if they did not provide sufficient methodological details or if they were not related to the valorisation of agricultural waste for bio-composite materials development. Finally, it identified major challenges such as moisture absorption and fibre inconsistency and outlined future research directions, including the optimisation of hybrid composites and advanced manufacturing processes, to improve the performance of agricultural waste as an eco-friendly material, such as rice husk-palmyra fruit fibre reinforced in a thermoplastic matrix, such as polypropylene.