Maleinized liquid polybutadiene (LPM) and its derivatives (half-esterified, LPME) were neutralized by alkaline solution to obtain an aqueous solution. The effects of these oligomer surfactants as dispersing agents on aqueous dispersion systems of inorganic pigments (TiO2, ZnO and CaCO3) and organic pigments (Hanza Yellow and Phthalocianine Blue) were examined.
Their dispersing action was more effective than common dispersants on the market. A series of evaluation tests on the effects of the surfactants as dispersant on various water-based paints was carried out to find the best dispersing action and good water-resistency of film obtained from these paints.
The order of the solubilizing power (the number of moles of dimethylaminoazobenzene, DMAB, solubilized per moles of dispersant monomer) of LPM and LPME was found to be as follos :
LPME (h) *1>LPM (L) *2>LPME (l) *3>LPM (H) *4
*1 esterified LPM (H) by higher alcohol
*2 low Acid Value (AV) LPM, AV=100mg KOH/g LPM
*3 esterified LPM (H) by lower alcohol
*4 high Acid Value LPM, AV=200mg KOH/g LPM
This order is essentially the same as that for the conversion of the emulsion polymerization of styrene, using the above dispersants as emulsifiers.
The data presented above suggest the formation of aggregated micells of the dispersants and/or quasi-micells.