CHEMICAL-PROPERTIES OF WATER-SOLUBLE, NONIONIC AZO-COMPOUNDS AS INITIATORS FOR EMULSION POLYMERIZATION

Four kinds of water-soluble, nonionic azo compounds were studied in te rms of their decomposition rate and initiator efficiency in radical po lymerization, and then used for emulsion polymerization. They had rela tively low initiator efficiency from 0.09 to 0.46. It was attributed t o the susceptibility to a cage effect, depending on their molecular si ze and hydrophobicity. Four azo compounds initiated emulsion polymeriz ation but nonionic latex particles were not obtained unexpectedly. Met hanol-containing medium results in the formation of a bimodal particle size distribution as well as a bimodal molecular weight distribution. (C) 1996 John Wiley & Sons, Inc.