Development of a self-reinforced starch-derived film with biocompatibility and mechanical properties

The scraps produced while processing packaging materials will cause a waste of resources. In this study, starch-based self-reinforced film (SSRF) using thermoplastic starch (TPS, 45 wt%) and polypropylene (PP, 53 wt%) was developed. The effect of extrusion times (1-4 times) on the film structure and performance was explored. The results show as the number of extrusions increases, the color of SSRF deepens from gray-white to brown, and the crystallinity increases. The mechanical properties of the four types of SSRF first increase and then decrease. The 2-SSRF has the best performance, with tensile strength of 13.23 MPa, elongation at break of 61.35%, Young's modulus of 1128.99 MPa, and flexural strength of 33.19 MPa. Proper extrusion improves the compatibility of TPS and PP. However, repeated extrusion will cause PP degradation and TPS carbonization, reducing interfacial interaction. This study developed new starch-based self-reinforced film and provided theoretical guidance for reusing packaging material scraps.