Tailored Optical and Mechanical Properties of Nanocellulose Composites: From Green Natural Fibers to Strong Hybrid Reinforcements

Abstract

Nanocellulose is an emerging green material possessing many advantages, including biodegradability, light weight, superior strength, high transparency, and low coefficient of thermal expansion. This novel nanostructure was selected as core material in the Japanese Revitalization Strategy. Nanocellulose is a family referring to many nanostructured celluloses with various size and aspect ratios, such as nanocellulose crystals (NCCs) and nanocellulose fibers (NCFs). NCCs are short, brittle, and highly transparent, while NCFs are long, flexible, and superior ductile. Both are promising reinforcements, but the hybrid effect of NCCs and NCFs are rarely found in previous research. The purpose of this study is to tailor optical and mechanical properties of nanocellulose composites using various ratios of NCCs/NCFs, and then further observe any synergism between NCCs/NCFs. The experimental method was divided into four phases, including acid hydrolysis to prepare NCCs, tailoring the formula of composites (NCCs/NCFs/Epoxy), removing water by solvents, and then finally curing the composites by amine crosslinker. The results show the newly prepared composites have less density than glass, ten times more in tensile strength, and competitive transmittance in optical properties. Our future work will apply this newly developed composite in flexible electronic substrates, such as smart windows and solar panels.