A new type hydrophilic monomer (K600) with both ionic groups and nonionic segments is synthesized from polyethylene oxide (Mn=600) and 1

2

4

5-benzenetetracarboxylic dianhydride (BTDA)．The synthesis process is monitored with FT-IR．Several selfemulsifiable polyurethane emulsions are prepared from isophorone diisocyanate(IPDI)

poly(butylene adipate)(PBA) and K600 in a prepolymer mixing process using substantial amount of solvent．The acid groups are neutralized with triethylamine (TEA)．The emulsion based on dimethylolpropanic acid (DMPA) is prepared by the same procedure for comparison．The effect of K600 content on the characteristics of emulsions

such as visual appearance

particle size

viscosity

durability to frost

electrolytes and variation of pH．are studied．Since K600 has been neutralized with TEA to give an anionic species

which is hydrophilic in nature

the hydrophilicity of polymer chains increases with increasing the K600 content．As a result

the particle size becomes finer(<100 nm) while the emulsion appearance varies from white to translucent and the viscosity of emulsion increases accordingly．In the meantime

the ionic groups and nonionic segments have a synergistic effect．The emulsion with over 1.7 wt％ carboxyl content can endure high temperature (80℃) for more than 120 h and the variation of emulsion viscosity is very low after frost．The emulsion with over 1.0 wt％ carboxyl content is stable within a pH range from l to 14 and can be mixed with l0％ NaCl solution at any ratio without any sedimentation．On the other hand．the emulsion based on DMPA is very sensitive to the variation of pH values and electrolytes．In conclusion

K600 can provide the emulsions excellent stability．