Switchable Block Copolymer Surfactants for Preparation of Reversibly Coagulatable and Redispersible Poly(methyl methacrylate) Latexes

Abstract

ethyl methacrylate)block-poly(methyl methacrylate) (PDMAEMA-b-PMMA) has been used as a surfactant in the preparation of PMMA latexes that can be coagulated and redispersed reversibly. In this work, we investigated in detail the effects of the block copolymer composition on the coagulation/redispersion performance of the latexes. A series of well-defined PDMAEMA-b-PMMA samples that have 10−30 DMAEMA units and 5−45 MMA units were synthesized through a two-step solution RAFT polymerization process and were used as the surfactant in the emulsion polymerization of MMA. PMMA latexes obtained with surfactants having MMA weight fraction (F MMA ) < 58.5% were stable. The particle size of the resulting PMMA latexes decreased gradually with the increase of F MMA . The latex particles initially coagulated with a small amount of caustic soda could be repeatedly redispersed into fresh water through CO 2 bubbling with ultrasonication and coagulated through N 2 bubbling with some heating. The coagulation/redispersion process was repeatable through the CO 2 /N 2 bubbling. The latexes showed excellent redispersibility with the surfactants of F MMA < 46%. With F MMA > 46%, the latex particle sizes could increase over 20% after the coagulation/redispersion process.

CO2-responsive polymeric materials: synthesis, self-assembly, and functional applications

“…1 Therefore, post-washing steps are required for removing these chemicals and a large volume of waste water is produced, which leads to the increase in the cost and environmental impact of the process. 77 Switchable surfactants can address the above-mentioned concerns. Because a large fraction of the mass of a latex is water, shipping latex from one location to another means additional cost for the transportation of water.…”

“…The structure of the head group can change solubility, basicity, heat of protonation, and the heats of CO 2 -switchability of the surfactant. 77,101 The latex stability depended on the diblock copolymer composition, and the latex particle size decreased with increasing weight fraction of MMA (F MMA ). 7,10,99 However, in some cases, the surfactant is not available commercially and needs to be synthesized.…”

Carbon nanotubes, graphene, and their derivatives for heavy metal removal

“…Besides that, polymers, especially those with electron-donating or alkaline groups, are increasingly applied to various carbon nanoadsorbents. They have many advantages over other materials, such as tailored molecular weight, chain topology, and functional groups [152][153][154]. Moreover, they are usually nontoxic as a result of their large molecular size, which will dramatically reduce the secondary pollution [155,156].…”

Highly CO2/N2-Switchable Zwitterionic Surfactant for Pickering Emulsions at Ambient Temperature

“…Their use facilitates product separation, transportation and storage, saving energy and material costs. [2][3][4][5][6][7] There have been a significant number of switchable surfactant structures reported in literature. The external stimuli utilized has included radiation, redox reagents, acids/bases, magnetism, temperature 1 and, more recently, gases such as CO 2 .…”