Thermal behavior, decomposition mechanism and some physicochemical properties of starch-g-poly(benzyl acrylate) copolymers

TG/FTIR/QMS-coupled method to study the thermal behavior along with the evolution of volatile decomposition products and thus the decomposition mechanism under inert conditions of some starch-g-poly(benzyl acrylate) copolymers was applied. Starch-g-poly(benzyl acrylate) copolymers under K2S2O8-initiated copolymerization process of benzyl acrylate monomer with gelatinized potato starch were prepared. The ATR-FTIR and 13C CP/MAS NMR confirmed the successful formation of grafted polymers with different grafting parameters such as grafting percent (%G) and grafting efficiency (%GE). The evolution of some physicochemical properties such as swelling, moisture resistance and chemical resistance allowed certifying that the copolymers obtained were more resistant toward polar solvents, moisture and acidic medium due to the incorporation of more hydrophobic chains into starch backbone as compared to unmodified potato starch. The TG/FTIR/QMS studies confirmed their similar thermal stability, two stage decomposition process but different and more complex decomposition mechanism under the second decomposition stage as compared to the previously presented starch-g-poly(benzyl methacrylate) copolymers.