Hybrid Sugarcane Bagasse–CNSL Bio-Composites: A Review on Developments, Optimization, and Automotive Applications

Abstract

Growing interest in lightweight, economical, and eco-friendly materials has pushed researchers toward natural-fiber-based bio-composites for automotive applications. This review examines recent progress in hybrid sugarcane bagasse composites made with CNSL (Cashew Nut Shell Liquid) resin and discusses how these materials can be refined to serve as practical alternatives to traditional synthetic composites. The main highlights of the sugarcane bagasse which is an agricultural waste product of sugar industry is the good strength to weight ratio, biodegradability, and low density. Hybridization with complementary fibers—either natural or synthetic—has emerged as an effective strategy to improve strength, stiffness, impact resistance, and thermal stability. Parallelly, the incorporation of hardeners into CNSL resin enhances crosslinking, curing behavior, and load transfer efficiency, contributing to more reliable composite structures.

This review synthesizes studies on fiber treatments, hybrid fiber combinations, CNSL–hardener formulations, fabrication processes, and the influence of processing parameters on the resulting composite properties. Studies on mechanical, thermal, and microstructural behavior show that well-designed hybrid bagasse–CNSL composites offer better performance and can be used in several semi-structural and interior automotive parts such as dashboards, door panels, trims, and impact-absorbing sections. However, some issues still need attention, particularly moisture uptake, inconsistency in natural fiber quality, variations in resin behavior, and the lack of uniform testing standards.