Tuning CO2-induced reversible redispersion or irreversible destabilisation for latex separation

• Published in: Journal of colloid and interface science Vol. 573; pp. 250 - 262
• Main Authors: Mu, Meng, Yuan, Rui, Zhang, Ganghong, Wu, Dianguo, Quan, Hongping, Han, Peihui, Feng, Yujun
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.08.2020
• Subjects: CO2-switchable; Dispersion/coagulation transition; Electrostatic interaction; Polymer colloids; Swelling/deswelling transition; Swelling/deswelling transition; CO2-switchable; Polymer colloids; Electrostatic interaction; Dispersion/coagulation transition
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2020.03.121

[Display omitted] The CO2-sensitive dispersion/precipitation transition of polymer latexes fabricated based on a responsive emulsifier is a promising way to conveniently acquire bulk polymer materials. Nevertheless, the tedious synthesis procedures for switchable surfactants and the harsh operating requirements for the sensitive latexes constrain the applicability of the approach for latex preparation. Therefore, a new strategy for generating latexes with tunable CO2 responsiveness in a maneuverable way is urgently needed. In this work, a CO2-switchable electrostatic interaction is introduced to construct responsive latexes. A series of lightly crosslinked poly(diethylaminoethyl methacrylate-styrene) [P(DEA-St)] latexes with different PDEA contents were fabricated via one-pot emulsion copolymerization, with divinylbenzene and sodium dodecylsulfate (SDS) used as the crosslinker and anionic emulsifier, respectively. The influence of the DEA feeding ratio on the resulting P(DEA-St) colloids was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Then, a cyclic CO2/N2 input was introduced to verify the response transitions of polymer latexes. Accompanied by the stepwise decrease of DEA feeding ratio, the morphology of the resulting copolymerized nanoparticles changed from an ambiguous bulge to the typical spherical pattern. In addition, the P(DEA-St) latexes treated by cyclic CO2/N2 exhibit four different types of response modes, namely (i) CO2-switchable swelling/deswelling transition, (ii) CO2-reversible dispersion/coagulation transition, (iii) CO2-induced irreversible destabilisation and (iv) CO2-insensitive latexes. The CO2-responsive destabilisation is highly applicable in the separation and transportation fields of commercial latex products, such as poly(methyl methacrylate), poly(n-butyl acrylate) and poly(butyl methacrylate) colloids.