Investigation of Mechanical, Thermal, and Biodegradation Properties of Starch-Based Biopolymer Composites Reinforced with Natural Fibres

Abstract

Biopolymers made up of starch are suitable alternatives to petroleum-based plastics due to their renewability, cost-efficiency, and biodegradability, although their brittleness, moisture sensitivity, and low thermal stability limit their application. Fibre reinforcement is commonly cited as the solution to such limitations while maintaining biodegradability. This paper provides an evidence-based analysis of how fibre reinforcement influences the mechanical, thermal and biodegradation characteristics of starch-based composites. An analytical framework connecting the formulation factors, interface mechanisms, and outcomes is suggested, and fifteen scientific studies published between 2021 and 2026 are synthesized. Quantitative evidence on a completely characterized thermoplastic cassava starch/candelilla wax composite with 0-60 wt% Pennisetum purpureum fiber reinforcement reveals that density, equilibrium moisture absorption, and water solubility were reduced by 17.3%, 53.7%, and 55.1%, respectively, at 60 wt%, while soil burial weight loss decreased from 67.4% to 43.4The mechanical performance of the composite is optimal around 50 wt% fibre until void formation and agglomeration start to dominate. Thermal performance increases with the temperature at which the material starts to decompose. Biodegradation is reduced but not prevented. The study provides guidelines on the loading range from 40 to 50 wt% and research needs.