Effect of cationic monomer structure on the aggregation behavior of amphoteric acrylic polymer around isoelectric point  

作　　者：Qijun Li Yudan Yi Ya-nan Wang Jing Li Bi Shi 

机构地区：[1]Key Laboratory of Leather Chemistry and Engineering(Sichuan University),Ministry of Education,Chengdu 610065,China [2]National Engineering Laboratory for Clean Technology of Leather Manufacture,Sichuan University,Chengdu 610065,China [3]Sichuan Tingjiang New Material,Inc.,Shifang 618412,China.

出　　处：《Journal of Leather Science and Engineering》2022年第1期52-60,共9页皮革科学与工程（英文）

基　　金：the Tianfu Ten-thousand Talents Program of Sichuan Province and the National Key R&D Program(2017YFB0308500).

摘　　要：Amphoteric polymer can be used as retanning agent in leather manufacture. It is particularly useful in chrome-free tanning systems since it can regulate the charge properties of chrome-free leather and enhance the fixation of anionic post-tanning chemicals in leather. However, the aggregation and precipitation of amphoteric polymer retanning agents around the isoelectric point (pI) hinder their wide application. Herein, we synthesized five amphoteric acrylic polymers (AAPs) by free radical copolymerization with acrylic acid and five different cationic acrylic monomers. The effect of cationic monomer structure on the aggregation behavior of AAPs was investigated. The aggregation of AAPs in aqueous solution showed pH and concentration dependence. Light scattering analysis showed that Poly (AA-co-MAPTAC) and Poly (AA-co-DMAPMA) were in the shape of coiled linear flexible chains with small particle size (Rg 7.6 nm and 14.8 nm, respectively) near the pI. However, Poly (AA-co-DAC), Poly (AA-co-DMC) and Poly (AA-co- DMAEMA) were in the shape of hollow spheres and exhibited serious aggregation. Quantum chemical calculations suggested that the amide groups in the cationic monomers MAPTAC and DMAPMA enhanced the nucleophilicity of AAPs. Thus the corresponding AAPs could carry a large number of cationic charges to slow their aggregation when the pH just climbed over the pI. The results are expected to provide theoretical reference for the synthesis and widespread application of AAPs.

关 键 词：Amphoteric acrylic polymer Isoelectric point Aggregation behavior Cationic monomer RETANNING 

分 类 号：TS529.2[轻工技术与工程—皮革化学与工程]