Octadecyl Maleamic Acid Salt As a Microreactor for Its Copolymerization Reaction with Butyl Acrylate in Aqueous Medium

Abstract

The hydrogelator, octadecyl maleamic acid salt (ODMAS), has been shown to perform as a microreactor in copolymerization reaction with butyl acrylate in aqueous medium thereby providing functionalized latex. The evidence for occurrence of controlled polymerization reaction inside the microreactor is drawn from the composition and the polydispersity index of the copolymers. The copolymers generated under microreactor conditions or in other words, from emulsion phase provided by the hydrogelator exhibit significant incorporation of ODMAS with narrow polydispersity index. For example, a copolymer with ODMAS as high as 0.62 m and polydispersity index at 1.39 could be achieved. On the contrary, the solution copolymerization reactions in THF resulted in low yield of polymers with molecular weight at 10(3) order and polydispersity index in range of 2.53-2.91. The particle size distribution of the latexes remains almost invariant at 74 +/- 4 nm, over the concentration range of 0.12-0.62m with standard deviation (sigma) of 0.12-0.22. The surface area/molecule of ODMAS on the latex particle has been estimated to be 0.21 nm(2)/molecule. The polymerized latexes exhibit zeta potential at 64 +/- 3 mV and surface tension in range of 42.8-47.9 mN m(-)(1) respectively. This is indicative of coverage of latex with ODMAS.