The Influence of Cellulose Fiber Content on the Mechanical Properties of Composites Based on Modified Thermoplastic Starch

This study presents the results of evaluating composites based on modified thermoplastic starch (TPS) with BWW40 and FD600/30 cellulose fibers at varying mass contents. The aim of this study was to assess the effect of filler type and quantity on mechanical properties and water absorption. Test samples were prepared using the injection molding method. It was shown that increasing fiber content led to a reduction in strength of approximately 36% for BWW40 fibers and approximately 37% for FD600/30 fibers at maximum fill. Similar results were observed for elongation at break. Young’s modulus increased by approximately 15% for BWW40 fibers and approximately 13% for FD600/30 fibers. Water absorption also increased with increasing fiber content, which is due to the hydrophilic nature of both the starch matrix and the reinforcing phase. The main conclusion drawn from the conducted research is that by properly selecting the type and content of fibers, it is possible to consciously shape the stiffness and dimensional stability of such composites while maintaining their biodegradability. The results obtained allow for a better assessment of the application potential of these materials in the context of developing sustainable material solutions.