MORPHOLOGY AND RHEOLOGICAL BEHAVIOR OF CATIONIC POLYURETHANE/POLYDIMETHYLSILOXANE SELF-EMULSIFYING MICRO EMULSION
阳离子型自乳化端羟基硅油/聚氨酯微乳液的形态及流变性能

With the action of catalyst and cosolvent,a series of hydroxyl-terminated polydimethylsiloxane (HPMS) based polyurethane (PU) micro emulsion were successfully prepared by self-emulsifying copolymerization.They were prepared by the reacton of isophorone isocyanate (IPDI),poly(tetramethylene oxide)glycol (PTMG) and HPMS with N-methyldiethanolamine (MDEA) as chain extender and trimethylolpropane (TMP) as crosslinker.Effects of HPMS content on the particle size and morphology of HPMS/PU micro emulsion were analyzed.The effects of HPMS content,N-methyldiethanolamine content,TMP content,and the molecular weight of the prepolymer on the emulsion's rheological properties were studied.The results revealed that the average diameter of the particles and the distribution width became greater and wider with HPMS addition.Emulsions exhibit a Non-newtonian behavior,and they are endowed with pseudoplasticity and thixotropy.It is noticed that the apparent viscosity decreases with increasing the shear rate,that is,the emulsions show a characteristic of shear thinning,and their flow-behavior index (n) ranges from 0.885 to 0.531.It is also noticed that their zero shear viscosity ranges from 13.59 mPa5s to 25.08 mPa5s,changing with the content of HPMS,N-methyldiethanolamine,TMP and the molecular weight of the prepolymer.