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

在催化剂和少量助溶剂的作用下,以端羟基硅油(HPMS)/聚(四亚甲基醚)二醇(PTMG)为软段,异佛尔酮二异氰酸酯(IPDI)为硬段单体,以三羟甲基丙烷TMP为交联剂、N-甲基二乙醇胺(MDEA)为扩链剂合成了一系列自乳化双软段HPMS/PU微乳液.分析了HPMS用量对HPMS/PU微乳液粒径及微观形态的影响;研究了HPMS/PU中HPMS含量、MDEA用量、TMP用量、预聚体分子量对其流变性能的影响.研究结果表明,HPMS的加入使乳液粒径增加,HPMS/PU乳液为非牛顿流体,且具有一定的假塑性和触变性,表观粘度随切变速率的变化规律呈现一定的切力变稀特征,流动指数范围为0.885~0.531之间;其零剪切粘度值为13.59~25.08mPa.s,随HPMS用量、MDEA用量、预聚体相对分子质量、TMP用量而异.

MORPHOLOGY AND RHEOLOGICAL BEHAVIOR OF CATIONIC POLYURETHANE/POLYDIMETHYLSILOXANE SELF-EMULSIFYING MICRO EMULSION

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.