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采用无溶剂一步法,在聚氨酯主链上引入乙氧基悬挂链,制备了水性高固含量乙氧基悬挂链聚氨酯(WHPU)。考察了软段相对分子质量和软段含量对WHPU乳液及涂膜性能的影响。结果表明:随着软段含量和软段相对分子质量的增加,乳液平均粒径减小,粒径分布变窄,乳液黏度增大;当以相对分子质量为1 000 g/mol和2 000g/mol的PTMG为复合软段,二者摩尔比为1,其含量为55%时,制得的聚氨酯乳液固含量可达50%以上,乳液粒径呈双峰分布,黏度较小,涂膜具有一定的微相分离,低温转变温度(Tg)为-72.6℃,热分解温度为293℃,成膜抗张强度可达35.7 MPa,断裂伸长率可达760%,材料的综合性能较好。
A one - step solvent - free method was used to introduce ethoxy dangling chains onto the polyurethane backbone to prepare waterborne high solids ethoxylated chain suspended polyurethanes (WHPU). The effects of soft segment relative molecular mass and soft segment content on WHPU emulsion and film properties were investigated. The results showed that with the increase of the soft segment content and the relative molecular mass of the soft segment, the average particle size of the emulsion decreased, the particle size distribution became narrower and the viscosity of the emulsion increased. When the relative molecular mass was 1 000 g / mol and 2 000 g / mol of PTMG is a soft soft segment with molar ratio of 1 and its content of 55%, the prepared polyurethane emulsion has a solid content of more than 50%, a bimodal distribution of emulsion particle size and a small viscosity, A certain micro-phase separation, low temperature transition temperature (Tg) of -72.6 ℃, thermal decomposition temperature of 293 ℃, film tensile strength up to 35.7 MPa, elongation at break up to 760%, the overall performance of the material better.