硬段含量对水性聚氨酯性能的影响

以聚酯多元醇、二羟甲基丙酸(DMPA)、甲苯二异氰酸酯(TDI)和1,4-丁二醇(BDO)为主要原料,合成了阴离子型WPU(水性聚氨酯),并着重探讨了聚氨酯(PU)分子链中硬段含量对其性能的影响。结果表明:随着PU分子链中硬段含量的不断增加,硬段的Tg(玻璃化转变温度)上升,但软段的Tg呈先升后降态势,WPU的外观由半透明泛蓝光转变为乳白色不透明(稳定性变差),并且WPU的黏度、耐水性和T型剥离强度均呈先升后降态势;当WPU中w(硬段)=22.79%时,相应WPU的综合性能相对最好,用其胶接聚酰胺(PA)/聚丙烯(PP)复合薄膜的T型剥离强度达到0.488 kN/m。

Influence of hard segment contents on properties of waterborne polyurethane

With polyester polyol,dimethylol propionic acid(DMPA),toluene diisocyanate(TDI) and 1,4-butanediol(BDO) as main raw materials,an anionic type WPU(waterborne polyurethane) was prepared,and the influences of hard segment contents in PU(polyurethane) molecular chain on its properties were emphatically discussed.The results showed that the Tg(glass transition temperature) of hard segment was increased but Tg of soft segment had trend of rise-fall,the appearance of WPU was changed from translucent with blue into opaque with milky white(its stability had trends of fall),and WPU's some properties(such as viscosity,water resistance and T-peeling strength) had all trends of rise-fall with increasing hard segment contents in PU molecular chain.The corresponding WPU had the relatively best combination property because the T-peeling strength of polyamide(PA)/polypropylene(PP) composite film bonded by the WPU adhesive was 0.488 kN/m when mass fraction of hard segment in WPU was 22.79%.