Synthesis and Characterization of Photo‐Graft Copolymers of Sodium Salt of Partially Carboxymethylated Tamarind Kernel Powder

In the present case, the functionalization of sodium salt of partially carboxymethylated tamarind kernel powder (Na‐PCMTKP, DS¯= 0.15), an industrially important natural polymer, is carried out through photo‐graft copolymerization of methyl methacrylate (MMA) and ethyl methacrylate (EMA) onto it using ceric ammonium nitrate (CAN) as a photo‐initiator. The effects of the concentrations of photo‐initiator (CAN), nitric acid, methacrylate monomers (MMA and EMA) and the amount of Na‐PCMTKP as well as reaction time and temperature on photo‐graft copolymerization are being investigated to achieve the maximum graft yields (%G = 232.2 and %GE = 91.0 in the case of MMA and %G = 206.2 and %GE = 90.0 in the case of EMA). A suitable mechanism to explain the photo‐graft copolymerization is being proposed. The kinetics aspect of the photo‐graft copolymerization is also studied and the values of the overall activation energy for the photo‐graft copolymerization in the case of MMA and EMA are found to be 8.10 and 10.49 kJ mol−1, respectively. Besides kinetics study, the chemical structure and thermal properties of the graft copolymers of Na‐PCMTKP containing PMMA and PEMA is studied by FTIR, TGA, and SEM techniques and the results ascertains the evidence of the successful photo‐graft copolymerization of both the methacrylate monomers onto Na‐PCMTKP. The synthesized novel graft copolymers may find their potential applications to be used as metal adsorbents as well as novel excipients for direct compression matrix tablets.