【作者】 孙平川； 徐璐； 李宝会； 陈铁红； 金庆华； 丁大同；

【Author】 Sun Pingchuan~1 Xu Lu~2,Li Baohui~2,Chen Tiehong~1 Jin Qinghua~2 Ding Datong~2 1 Key Laboratory of Functional Polymer Materials,Ministry of Education,College of Chemisty, 2 Department of Physics,Nankai University,Tianjin 300071

【机构】 功能高分子材料教育部重点实验室,化学学院,南开大学； 物理学院,南开大学；

【摘要】 <正>大分子间及水分子与大分子间相互作用,特别是氢键相互作用,在聚合物及生物材料的结构、功能及动力学等方面起着至关重要的作用。聚丙烯酸(PAA)及其共聚物中由于侧链的羧酸基团容易形成氢键,可与其它聚合物形成相容的高性能聚合物及制备 pH 敏感凝胶和更多还原

【Abstract】 Hydrogen bonds and adsorption of water in poly(acrylic acid)were studied by solid-state 1D and 2D CRAMPS and double-quantum ~1H NMR using continuous phase modulation technique for proton-proton homonuclear dipolar decoupling(DUMBO1).It was found that three types of COOH groups formed by means of hydrogen bonds with different chemical shifts and dynamics.Three states of water can also be determined in PAA/water system:free water,two kinds of bound water including those formed by means of water-water and water-polymer hydrogen-bonding interactions. Double-quantum and dipolar filter ~1H NMR spectra were used to distinguish these groups with different dynamics.2D proton-proton spin diffusion correlation experiments were further used to determine the 1H-1H proximity and the average COOH domain size.It also reveals that the adsorbed water is in proximity with free mobile COOH,and far from the rigid chains that form strong hydrogen bonds.The above NMR results further reveal that the inter-polymer hydrogen-bonding increase with increasing of adsorbed water,this enhances the mobility of polymer chains and promotes the formation of inter-polymer hydrogen bonds.更多还原