Prepration of amphoteric carboxyalkyl-quaternary ammonia chitosan derivatives and performances on both scaling inhibition and bacterial inhibition

Chitosan was modified by chloroacetic acid,acrylic acid and 2,3-epoxypropyl trimethyl ammonium chloride to obtain amphoteric carboxymethyl-quaternary ammonium chitosan(CMQAC)and amphoteric carboxyethyl-quaternary ammonium chitosan(CEQAC),then the structures of the products were confirmed by IR,1H NMR and XRD.The performance of scaling inhibition of amphoteric chitosan derivatives with respect to CaSO4 were evaluated by static antiscaling experiment,and the results showed that the inhibition rate could be up to 100% when the dosage of amphoteric chitosan derivatives was 16 mg/L,2000 mg/L and 4800 mg/L.The bacterial inhibition of amphoteric chitosan derivatives with different degrees of substitution(DS)of quaternary ammonium was measured with the vial method.The results showed that the sterilizing rates can be up to 99.7% and 99.2% with chitosan derivative addition of 30mg/L when the DS of quaternary ammonium was 0.73 and 0.50 respectively for CMQAC and of CEQAC.The modification resulted in a great improvement in scaling inhibition and bacterial inhibition of chitosan derivatives in comparison with chitosan.