The amphoteric copolymer P(AM-co-AA-co-DAC-co-DMC) was synthesized by dispersion polymerizationin in ammonium sulfate aqueous solutions

in which noionic monomer acrylamide (AM)

anionic monomer acrylic acid (AA)

cationic monomer acryloyloxyethyltrimethyl ammonium chloride (DAC) and cationic monomer methacryloyloxyethyltrimethyl ammonium chloride (DMC) were used as raw materials.The characteristics of copolymers were studied by means of FTIR

13C-NMR

transmission electron microscopy(TEM) and other methods.The effects of different dispersants

the molar ratio of anionic monomer to cationic monomer and pH on the dispersion polymerization process and the stability of the dispersion system were investigated.The results showed that when the amphoteric copolymer P(AM-co-AA-co-DAC-co-DMC) was synthesized in the ammonium sulfate aqueous solution

to obtain a relatively stable dispersion system

it should choose to use nonionic dispersion stabilizer or cationic dispersion stabilizer as polymeric stabilizer

such as polyvinylpyrrolidone (PVP)

poly(methacryloyloxyethyltrimethyl ammonium chloride) (PDMC) and poly\|(acryloylxyethyltrimethyl ammonium chloride)(PDAC) should be used

and its pH should be between 2 and 4.Amphoteric nano-copolymers with more than 25% total ion exponent can be obtained under the following optimized conditions:a mass fraction of polymeric stabilizer polyvinylpyrrolidone (PVP) is 1.5%

an initiation temperature is 40℃

pH = 3

the molar ratio of ionic monomer to cationic monomer is less than 1.