Polymer composites/nanocomposites reinforced with rice husk and derived fillers—promising sustainable solutions for technological sectors

Rice husk (rice milling byproduct) stands out as low cost, low density, biodegradable, and sustainable filler to enhance physical properties of variety of thermosets, thermoplastics, and conjugated polymers. To further improve the material compatibility/performance, rice husk has been modified via physical/chemical modification strategies. Moreover, rice husk has been used in combination with other efficient nanoparticles (like nanocarbons). Furthermore, rice husk has been employed as precursor material to form carbon nanoparticles (graphene, graphene oxide, carbon nanotube) and inorganic nanoparticles (silica). Hereafter, rice husk, surface treated rice husk, rice husk bifillers, and rice husk derived nanoparticles have been integrated in polymers; thereby imparting upgraded structure-properties-performance (morphological, mechanical, thermal, nonflammability, heat/charge conduction, permeability) aspects to the composites/nanocomposites. Looking at field progress, this review is aimed to systematically highlight fundamentals of rice husk and polymer/rice husk composites. After outlining essential characteristics, numerous categories of polymer/rice husk/nanocarbon nanocomposites and polymer/rice husk derived nanofiller hybrids have been surveyed. Afterwards, major sections address applied sectors of polymer/rice husk hybrids, including structural engineering (aeronautics, automotive, civil), environmental membranes (water purification, gas separation), and energy devices (supercapacitors, batteries). Toward the end, this manuscript identifies issues and proposes solutions for expanding industrial scale relevance of rice husk based high-tech materials.