摘要
对本征态聚苯胺热处理过程中红外光谱的变化进行了在线测试,结果表明,加热过程中聚苯胺的红外光谱发生显著变化,表征醌式结构的特征峰持续减弱;表征苯式的特征峰先减弱,当温度超过100℃后强度增加。认为聚苯胺在热处理过程中由不稳定的醌式结构向稳定的苯式结构转化,具体是通过分子链之间发生交联反应完成的。这种交联反应从较低的温度起(～100℃)就已发生。
In-situ infrared spectroscopy studies of intrinsic polyaniline undergoing heat treatment have been accomplished. The results show that there are marked changes in polyaniline′s infrared spectra when it is heated from room temperature to 210 ℃. The characteristic peak of (quinoid/imine) units attenuate continuously since heating started; the characteristic peak of (benzenoid/amine) units increase when the temperature exceed 110 ℃, after a first drop down. This results is opposed to primary assumption, that the oxidized (quinoid/imine) units would increase its content when the intrinsic polyaniline is heated in air. We conclude that (quinoid/imine) units is not stable when polyaniline is heated, it will transform to reduced (benzenoid/amine) units. Consider another result is that there′s no increasing of characteristic peak of H (attached with N or benzene ring) during heat treatment, we suggest a reaction that neighboring polyaniline molecules react through a hydrogen migration process. This reaction mechanism could increase the content of (benzenoid/amine) units, it also meet the require to maintain H content. Finally we realized that this reaction is a crosslinking process indeed, which has been stated in many other documents. Based on the FT-IR results, we conclude that the crosslinking reaction of intrinsic polyaniline occurs in a relatively low temperature(~100 ℃), which is far below the values predicted by DSC method in many cases.
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2004年第5期121-124,共4页
Polymer Materials Science & Engineering
基金
国家自然科学基金(50203006和20034006)资助项目
