Preparation and preliminary of the CMCTS-g-(PDMMC-co-PDDAMC) polyampholyte

The novel polyampholyte derivate of chitosan, CMCTS-g-(PDMMC-co-PDDAMC), was prepared through the graft copolymerization of dimethylaminoethyl methacrylate methyl chloride(DMMC) and decyl dimethyl allyl ammonium chloride (DDAMC) on the chain of carboxymethyl chitosan, intiated by K₂S₂O₈/Na₂SO₃ redox initiation system. The polyampholyte properties of CMCTS-g-(PDMMC-co-PDDAMC) was studied primarily in this paper. The viscosity reached the maximum at pH=1 and pH=11 respectively. The viscosity was reduced to minimum around pH=5, which was the isoelectric point of the CMCTS-g-(PDMMC-co-PDDAMC) polyampholyte. At the isoelectric point, the viscosity and intrinsic viscosity of the CMCTS-g-(PDMMC-co-PDDAMC) solution was increased as the increase of the ionic strength. On the contrary, the viscosity of the CMCTS-g-(PDMMC-co-PDDAMC) solution was decreased as the increase of the ionic strength around pH=1 and pH=11. Effects of the type of cation on the viscosity of the CMCTS-g-(PDMMC-co-PDDAMC) solution were also studied.