NDI型聚氨酯弹性体的氢键研究

采用预聚物法合成了以聚四氢呋喃醚二醇(PTMG)、聚氧化丙烯二醇(PPG)、1, 5-萘二异氰酸酯(NDI)、1,4-丁二醇(BDO)、三羟甲基丙烷(TMP)等为主要原料的双组分浇注型聚氨酯弹性体。通过红外分析、差示扫描量热分析，对NDI型聚氨酯弹性体中存在的氢键进行了深入研究。结果表明，NDI型聚氨酯弹性体的亚氨基(N—H)完全氢键化，羰基(C＝O)氢键化程度高，微相分离严重；随着预聚物中异氰酸根含量的增加，硬段微区氢键化程度逐渐提高，其中有序氢键化程度逐渐升高，而无序氢键化程度随之下降；PTMG2000-NDI系聚氨酯弹性体的软段容易产生结晶，而DL2000-NDI系聚氨酯弹性体和PTMG1000-NDI系聚氨酯弹性体的软段无结晶行为；低聚物多元醇的种类及其分子量也是聚氨酯弹性体的氢键的重要影响因素。

Hydrogen bonding in polyurethane elastomers based on 1,5-naphthalene diisocyanate

Casting two-component polyurethane elastomers have been synthesized using polytetramethylene ether glycols (PTMG), polypropylene glycols (PPG), 1,5-naphthalene diisocyanate (NDI), 1,4-butanediol (BDO) and trimethylolpropane (TMP) as the main raw materials. By using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC), the distributions of hydrogen bonds in these polyurethane elastomers were characterized. The results showed that the polyurethane elastomers had a high degree of micro phase separation, and a high degree of hydrogen bonding, with the extent of N—H hydrogen bonding reaching 100%. With increasing NCO content, the degree of hydrogen bonding of the hard segment increased, and the degree of ordered also hydrogen bonding increased, but the degree of disordered hydrogen bonding decreased. Moreover, the type and molecular weight of the oligomer polyol had an important influence on the hydrogen bonding and phase structure of the resulting polyurethane elastomers.