Study on preparation of the novel CMCTS-g-(PAA-co-PDMDAAC) polyampholytic superabsorbent polymer

The polyampholytic superabsorbent polymer CMCTS-g-(PAA-co-PTMAAC) was prepared through graft copolymerization of trimethylallyl ammonium chloride (cationic monomer) and acrylic acid (anionic monomer) onto the chain of carboxymethyl chitosan, initiated by the redox initiator. The structure of the graft copolymer was characterized by FTIR. Effects of the reaction conditions on the swelling ratio of the polymer were studied. It was found that the optimization conditions to the synthesized polymer with the highest swelling ratio were as follows: the mass ratio of the crosslinking reagent to acrylic acid was around 1.4%, The mass ratio of the trimethylallylammonium chloride to the vinyl monomer was around 14.3%, (m_AA + m_TMAAC)/m_CMCTS was around 9.33, the neutralization degree of the acrylic acid ranges from 20% to 30%. Influence of the pH value of the solution on the water absorption properties of the polymers was studied. It was found that there was highest swelling ratio point at the acidic conditions and basic conditions respectively. The swelling ratio at the isoelectric point was relative low.