自旋标记法研究STVPh/PEO共混体系的链运动  

A Study of the Chain Motion in STVPh/PEO System by ESR Spin Label

作　　者：谭莉[1] 陈士明[1] 严小敏[1] 平郑骅[2] 沈伊民 

机构地区：[1]复旦大学分析测试中心,上海200433 [2]复旦大学高分子科学系,上海200433

出　　处：《高等学校化学学报》2003年第6期1114-1117,共4页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金 (批准号 :2 99740 0 6 )资助

摘　　要：利用自旋标记法将氮氧自由基连接在聚氧化乙烯分子末端 ,测得其与不同羟基含量的苯乙烯 -4 -乙烯基苯酚共聚物组成高分子共混体系的 ESR波谱 ,研究了各组分的分子链运动 .自旋标记聚氧化乙烯的 ESR谱图在整个温度范围内只显示快运动或慢运动的一种运动成分 ,表明氮氧自由基处于单一的环境中 .高分子共混体系的 ESR谱在一定温度范围内同时存在快运动和慢运动的两种运动成分 ,且两成分相对比例随温度的变化而变化 ,表明体系中氮氧自由基处于不同的微相环境中 .由 ESR谱得到的 T5m T,τc,Ea 的值都随着体系中羟基含量的增加而变大 ,显示标记分子的链运动在共混体系中的活动逐步受阻 .与此同时 ,随着该共混物中酚羟基和醚氧基间氢键相互作用强度的增大 ,共混物的相容性得到逐步改善 .The electron spin resonance(ESR) spectra of PEO end labeled with nitroxide groups were recorded over a temperature range for the bulk polymer and for(1∶3 by mass ratio) blends with styrene-vinylphenol copolymer(STVPh) containing different hydroxyl groups. For SLPEO, ESR spectra are composed of a single component, indicating the spin label locating in a single environment. For SP-1, SP-9 and SP-26 blends, two spectral components with different rates of motiona 'fast' component and a 'slow' component are observed in the experimental temperature range. It can be concluded that the fast and slow components should be attributed to micro heterogeneity in the blends: nitroxide radical trapped in the PEO rich and STVPh rich regimes in the blends, respectively. The miscibility of the blends increases with increasing hydrogen bonding density due to the specific interaction between hydroxyl groups in STVPh and the ether oxygen in PEO. Accordingly, the T 5 mT, E a, τ c values are increased owing to the decrease of the SLPEO mobility of chain motion with increasing hindrance of physical cross-linking density.

关 键 词：自旋标记法 STVPh/PE0 共混体系 链运动 氮氧自由基 聚氧化乙烯 苯乙烯-4-乙烯基苯酚共聚物 相容性 氢键 电子自旋共振 

分 类 号：O631.1[理学—高分子化学]