硬段含量对水性聚氨酯软段结晶性能的影响

摘要

The waterborne polyurethane emulsions( WPU) were synthesized with isophorone diisocyanate (IP-DI) , polybutylene adipate glycol (PBA) , hexamethylene diisocyanate ( HDI) , polybutyleneadipate glycol(PBA) as main raw materials. Effects of the hard segments content on the crystallization properties of soft segments and adhesive properties of WPU were studied by FTIR, DSC, XRD, SEM. The results showed that, with the increase of hard segments content, hydrogen bonds density and aggregation extent were improved, but the miscibility between two phases went up too. DSC and XRD spectrums indicated that, with the increase of hard segments content, the melting enthalpy and. melting temperature of soft segments as well as the value of crystal diffraction maximum peaks were decreased, which illustrated the crystallization properties of soft segments became poor. The adhesive properties test showed that the initial adhesive strength and crystallization properties were excellent in the presence of the low content of hard segments.%以异佛尔酮二异氰酸酯、六亚甲基二异氰酸酯、聚己二酸丁二醇酯为主要原料合成了水性聚氨酯( WPU),通过FT-IR、DSC、XRD、SEM表征手段,研究了硬段含量对软段结晶性及WPU粘结性能的影响.研究表明,随着硬段含量的增加,WPU分子链上氨基甲酸酯键之间的氢键化程度提高,软硬两相相混严重,WPU软段结晶熔融焓变小,熔融温度变低；结晶衍射峰变弱,软段结晶性变差；粘结性能测试表明,在硬段含量较低时,聚氨酯体现出良好的结晶性能,初粘性较好.