Studies on the properties and biodegradability of PVA/Trapa natans starch (N-st) composite films and PVA/N-st-g-poly (EMA) composite films

The morphological modification of Trapa natans starch was done by grafting the methylmethacrylate (EMA) using ferrous ammonium sulphate‑potassium persulphate as a redox initiator. Different reaction parameters such as reaction temperature, time, monomer concentration, pH and solvent were optimized to get maximum graft yield (56%). The graft copolymers thus formed were characterized by Fourier transform infrared, scanning electron microscopy, X-ray diffraction and TGA/DTA/DTG techniques. PVA/starch (N-st) composite films and PVA/N-Starch-grafted-poly (EMA) composite films were prepared separately by using glycerol as a plasticizer. The effect and content of grafted starch on the mechanical properties, water uptake (%), and biodegradability of the composite films were observed. Elongation at break % of PVA/starch-grafted-poly (EMA) (1:1) increased up to 38.9% of pure PVA/N-starch composites (1:1). With further increase in the ratio of grafted starch from (50% to 70%) Elongation at break, % increased to a great extent. There was 223.14% increased in PVA/starch-grafted-poly (EMA) (3:7) as compared to pure PVA/N-starch (3:7) composite films. The Max stress increased up to 100% in PVA/N-starch-grafted-poly (EMA) (3:7) composite film of pure PVA/N-starch composite films (3:7). There were 41.63% decreases in water uptake in PVA/N-starch-grafted-poly (EMA) (3:7) composite films as compared to PVA/N-starch composite films. [Display omitted] •Ethyl methacrylate (EMA) was grafted onto Trapa natans starch using graft copolymerization•The effect and content of grafted starch on the different properties of the composite films was investigated.•The Elongation at break % and max stress enhanced significantly in PVA/starch-grafted-poly (EMA).•The water uptake (%) reduced significantly in synthesized composite films•Degradation rate of natural PVA/Starch composite film was faster than PVA/starch-grafted-poly (EMA).