Effect of Different Acrylic Acid Contents on LCST Behavior of Nanocrystalline Cellulose Grafted Random Copolymers of N-isopropylacrylamide and Acrylic Acid

Free and nanocrystalline cellulose (NCC) attached homopolymers of N-isopropylacrylamide and acrylic acid (AA) as temperature- and pH-sensitive materials and also their dual-sensitive copolymers with different contents of AA were synthesized by reversible addition fragmentation chain transfer polymerization. NCCs were obtained from microcrystalline cellulose by an acid hydrolysis process. In situ synthesis of polymers in the presence of 1 wt% of NCC was carried out at 70 °C via R-group approach. The lower critical solution temperatures (LCST) of polymers as phase separation temperatures were measured by the cloud point method using dynamic light scattering. LCST decreases in acidic and increases in basic conditions with increase in acrylic acid content and addition of NCC caused an increase in the slope of these variations slightly