HOMOPOLYMERIZATION AND COPOLYMERIZATION OF VINYL-ACETATE IN NONIONIC MICROEMULSIONS .1. A STUDY OF HOMOGENEITY DOMAINS

The homogeneity ranges of the systems consisting of the monomer (vinyl acetate or vinyl acetate + di-2-ethyl hexil maleate), cosurfactant (e thanol, n-propanol, n-butanol), surfactant (nonylphenol ethoxylate wit h 25 moles of ethylene oxide) and water were studied. Addition of the more hydrophobic comonomer requires utilization of a more hydrophobic cosurfactant. The increase of surfactant concentration entails the wid ening of the homogeneity range. The effect of the cosurfactants mentio ned is accounted for by the modification of the cluster structure of w ater. Therefore the refractive indexes and the signals of protons in N MR spectra vary non-linearly with the composition of homogeneous syste ms. DSC analysis of the systems obtained has come out with two crystal lization temperatures of water undercooled to -60 degrees C in systems of concentrations close to those of organic and aqueous phases. The r esults plead for the existence of a structure which differs from that of the ideal solutions of the systems studied.