Emulsifying and self-emulsified properties of siloxane polymer grafted with easy hydrophile

A series of siloxane polymers (SHE) with varying weight percents of simple nonionic hydrophilic groups have been synthesized and characterized by FTIR and ¹³C-NMR. Emulsions have been made by self-emulsification of those polymers in pure water and also by emulsifying silicone oil using those polymers as oil-in-water type emulsifiers. The stability of those emulsions have been examined apparently from the phase separation and also from the particle size increase on storage by Transmission Electron Microscopy (TEM) and photo microscopy. The results reviled that SHE 40, having 40 wt % grafted hydrophile, formed the most stable self-emulsified emulsion, and SHE30 and SHE40 could be used as effective emulsifiers for silicone oil emulsification. The possible use of those emulsions as a defoamer for water-borne systems has also been investigated by measuring the reduction of foam height of a strongly foamed aqueous solution of sodium lauryl sulfate (SLS). The defoaming ability decreases with the increase in hydrophile wt % in the polymer backbone; however, it increases with the emulsion (defoamer) concentrations. When compared with respect to the total wt % of hydrophobe contents in the emulsion defomer, the self-emulsified emulsion has shown better defoaming than the silicone oil emulsion, and the results are well in accord with the difference in size of the respective emulsion particles.