Graft copolymerization of Soy Protein Isolate with Polylactide via Ring Opening Polymerization

The present work is devoted to the graft copolymerization of polylactide onto soy protein isolate backbone by ring-opening polymerization in the presence of Sn(Oct), catalyst. The effect of various input parameters on the output parameters has been carried out to investigate the required levels to get an optimum product. Maximum graft yield of 81.4% polylactide-g-soy protein isolate could be obtained at 90 degrees C within 12 h and while using SPI amount 1.5g, 1g lactide and preswelling time of 14 h. Characterizations of the grafted polymers were carried out by various methods like Fourier transform infrared (FTIR) spectroscopy, Nuclear Magnetic Resonance (NMR) spectroscopy, thermal (TGA/DTA/DSC), X-ray Diffraction (XRD) and Field emission Scanning electron microscopy (FESEM). The swelling behavior of the SPI and grafted copolymers were studied in binary solvent (water: ethanol) system and the % swelling and % solubility has been determined.