Effects of Polymethacrylamide‐Grafted Branch on Mechanical Performances, Hydrophilicity, and Biodegradability of Thermoplastic Starch Film

Abstract To overcome the shortcomings of brittleness and high water uptake of thermoplastic native starch (TPNS) film, thermoplastic‐grafted starch (TPGS) film is prepared and tested using starch‐ g ‐polymethacrylamide (PMAM) with different percentages of grafting. Starch‐ g ‐PMAM is compounded in an internal mixer and then shaped by a compression molding machine to produce a TPGS film. Functional group analysis by Fourier transform infrared spectroscopy (FTIR) revealed that the graft copolymerization is successful, as evident from new characteristic infrared (IR) peaks of amide group (C═O stretching and N─H bending). TPGS films with MAM has more surface roughness than TPNS film does. With higher grafting percentages, the degrees of crystallinity and hydrophilicity of TPGS film reduce while the extensibility (based on strain at maximum load) and surface roughness increase, compared to that at lower percentages of grafting. The biodegradability of TPGS films grafted with MAM at different percentages is also examined.