Preparation and preliminary study on the novel CMCTS-g-GDDA polyampholyte

Carboxymethyl chitosan-g-hydroxypropyl decylalkyl dimethyl ammonium chloride (CMCTS-g-GDDA) was prepared via graft reaction of glycidyl decylalkyl dimethyl ammonium chloride onto the chain of carboxymethyl chitosan. The properties of CMCTS-g-GDDA were studied, and it was found that CMCTS-g-GDDA shows the properties of polyampholyte. The viscosity of CMCTS-g-GDDA reaches the maximum value at pH=2 and pH=12, respectively, and the minimum value around pH=7, which is the isoelectric point of the CMCTS-g-GDDA polyampholyte. At the isoelectric point, the viscosity of the CMCTS-g-GDDA solution increases with the increase of the ionic strength. CMCTS-g-GDDA shows good adsorption characteristics to the heavy ions at the weak acidity condition and the adsorption capacities decrease according to the order of Zn²⁺>Pb²⁺>Cd²⁺. The antibacterial activities of CMCTS-g-GDDA against Staphylococcus aureus and Bacillus subtilis are distinct. Using 0.039% CMCTS-g-GDDA solution, the antimicrobial zone diameters of above bacteria are (0.91±0.17) cm and (1.00±0.21) cm, respectively.