Thermal and mechanical properties of high-performance polyester nanobiocomposites reinforced with pre-treated sunn hemp fiber for automotive applications

The objective of this study is to create high-performance nano biocomposites by utilizing unsaturated polyester resin (PE) reinforced with pre-treated short (2 cm) lengthened sunn hemp (SH) fibers and by incorporating 5 % nanoclay (hydrophilic bentonite) through the compression molding technique. The addition of 5 % nanoclay to the biocomposite significantly increased the flexural strength by approximately 165 % for H₂O₂-treated SH fiber and 148 % for KMnO₄-treated SH fiber, when compared to untreated fibers. This enhancement was achieved through phase separation, intercalation, and exfoliation between the SH fibers, polyester resin (PE), and 5 % nanoclay. In particular, the H₂O₂-treated SH fiber nanobiocomposite exhibited a 43 % higher flexural strength compared to its corresponding biocomposite. The incorporation of nanoclay significantly decreased the water absorption of the bio-composites from 11.86 % in the untreated samples to a minimum of 2.76 % in the H₂O₂-treated SH/PE nanobiocomposite. The study suggests that short SH fiber/PE/nanoclay nanobiocomposites could be used as effective alternatives to synthetic composites in various applications, including the aerospace industry, household products, and automotive interior components such as side panels, seat frames, and central consoles. Additionally, they could be utilized in exterior parts like door panels and dashboards.