封端型水性聚氨酯树脂的结构与性能

Structure and Properties of Blocked Waterborne Polyurethane Resin

以聚酯多元醇、甲苯二异氰酸酯和二羟甲基丙酸为主要原料,丙烯酸单体封端,加入改性剂三羟甲基丙烷脱水蓖麻油酸酯(TMPDCO),制备出稳定的水性聚氨酯分散体。涂膜耐化学品性和凝胶含量测定说明,TMPDCO的加入增加了涂膜的交联度,提高了涂膜的耐化学品性。差示扫描量热法测试表明,加入封端剂增加了涂膜交联度,涂膜玻璃化转变温度明显提高。力学性能测试说明,聚酯作为软段的水性聚氨酯树脂较聚醚型耐水性好。X射线衍射分析说明,随着硬段规整度的增加,衍射峰中心依次向高角度偏移。红外表征说明,不同硬段合成水性聚氨酯的氨基甲酸酯键波数不同。

Series stable waterborne polyurethane dispersions have been prepared from toluene diimcyanate, polyester polyols and dimethylolpropionic acid, here, acrylic monomers as blocking agent, trimethylolpropane dehydrated castor oleate （TMPDCO）） as modification agent. The chemical-resistant and gel content of the films show that the crosslink degree and chemical-resistant of the films adding TMPDCO get improved much. Differential scanning calorimetric measurements of films show that the crosslink degree and Tg of the films get improved much while added blocking agent. The mechanical properties tests of the films show that the films of polyester polyols as soft-segment have lower chemical-resistant than polytetrahydrofuran glycol as soft-segment. X-ray diffraction analysis shows that diffraction peak center migrates to high angle in sequence with the hard segment having more structured degree. FT-IR tests show that carbamate wavenumber is different for the waterborne polyurethane synthesized by different hard segment.