摘要
异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)作为硬段,合成了水性聚氨酯。研究了硬段含量(质量分数)对乳液稳定性、膜耐热和力学性能等的影响。当硬段质量分数低于26%时,乳液贮存稳定性较差。随着硬段含量增加,聚氨酯膜拉伸强度迅速增加,断裂伸长率略有降低;红外光谱显示,自由的N—H伸缩振动峰强度减弱,氢键化N—H的振动峰强度增加;同时C O伸缩振动峰整体向低波数方向移动,C O伸缩振动峰峰形有明显的变化;DSC测试在50~125℃出现明显的氢键解离现象,吸热峰增强,证实了氢键作用力随着硬段含量的增加逐渐增强。TG测试表明,水性聚氨酯硬段和软段分步解离,随着硬段含量的增加,硬段分解温度降低,水性聚氨酯耐热性能下降。
A series of waterborne polyurethanes(WPU) were prepared from isophorone diisocyanate(IPDI) and dimethylolpropionic acid(DMPA),which acted as the hard segment.Effects of the hard segment content on the emulsion stability,thermostability and mechanical properties of WPU had been studied.When the mass fraction of the hard segment was below 26%,the emulsion stability was poor.With the increase of hard segment content,the tensile strength of the resultant film prepared from WPU increased quickly,and the breaking elongation decreased slightly;FTIR spectra showed that the intensity of free N—H stretching vibration peaks dropped,while the intensity of hydrogen bonded N—H stretching vibration peaks increased.At the same time,the peak shape of CO stretching vibration changed obviously and shifted to lower wave numbers.It is shown that the hydrogen bonds disaggregated evidently and the intensity of endothermic peak strengthened from 50 ℃ to 125 ℃ according to DSC analysis,suggesting that the hydrogen bonding strengthened gradually as the hard segment content increased.The TG curves indicated that the thermal decomposition of WPU was mainly a step-by-step decomposition of the hard and soft segments.The decomposition temperature of the hard segment and the thermostability of WPU decreased with the increase of hard segment content.
出处
《应用化学》
CAS
CSCD
北大核心
2011年第7期770-776,共7页
Chinese Journal of Applied Chemistry
基金
安徽省自然科学基金(070414193)资助项目
关键词
水性聚氨酯
硬段
氢键作用
热性能
waterborne polyurethane
hard segment
hydrogen-bonding action
thermal properties