Radically new cellulose nanocomposite hydrogels: Temperature and pH responsive characters

Innovation produced for synthesis of radically new stimuli-responsive hydrogels were described. The innovation is based on inclusion of cellulose nanowhiskers (CNW)-polyacrylamide (PAAm) copolymer in poly N-isopropyl acrylamide (PNIPAm) semi interpenetrating network (IPN) hydrogel. After being prepared as per free radical polymerization of AAm onto CNW, the as prepared copolymer was incorporated in a polymerization system, which comprises NIPAm monomer, bismethylene acrylamide (BMA) crosslinker, K2S2O8 initiator and TEMED accelerator, to yield CNW-PAAm-PNIPAm nanocomposite hydrogels. The latter address pH-responsive hydrogel as well as temperature-responsive. Hydrogels exhibit the highest equilibrium swelling ratio (ESR) in acidic medium (pH 4). Meanwhile they perform good swelling behavior and hydrophilicity at a temperature of 32 °C. These hydrogels carry the characteristic features of CNW-PAAm copolymer as conducted from FTIR and TGA. The hydrogels are homogenous and well-proportioned network structure with highly connected irregular pores with a large size ranging from 30 to 100 nm as concluded from SEM.