Synthesis of Emulsion-Templated Poly(acrylamide) Using CO2-in-Water Emulsions and Poly(vinyl acetate)-Based Block Copolymer Surfactants.
writer：Tan, Bien; Lee, Jun-Young; Cooper, Andrew I.
keywords：ScCO2
source：期刊
specific source：Macromolecules (Washington, DC, United States) (2007), 40(6), 1945-1954.
Issue time：2007年
We present here a simple and generic method for producing inexpensive and biodegradable polymer surfactants for use in supercrit. CO2. Low mol. wt. (Mw<7000 g/mol) hydroxyl-terminated poly(vinyl acetate) (PVAc-OH) was synthesized using optimized reaction conditions and iso-Pr ethanol (IPE) as the chain transfer agent. Oligomeric PVAc-OH (OVAc-OH, Mw<3000 g/mol) was then obtained by supercrit. fluid fractionation. The OVAc-OH species was converted to the imidazole ester by reaction with carbonyl diimidazole (CDI) and CO2-sol. surfactants were produced by coupling these reactive blocks with poly(ethylene glycol) Me ethers or poly(ethylene glycol) diols. The surfactants extremely effective in the prodn. of stable CO2-in-water (C/W) emulsions, which were then used as templates to produce emulsion-templated materials with unprecedentedly high levels of porosity for materials produced by this route. These hydrocarbon surfactants can out-perform perfluorinated species in applications of this type.