固体NMR 研究PMMA 纳米复合材料结构与受限链运动
收稿日期: 2014-05-01
修回日期: 2015-01-14
网络出版日期: 2015-03-05
基金资助
国家自然科学基金资助项目(21174072)，高等学校仪器设备共建共享资助项目(CERS-1-61).
Solid-State NMR Studies on the Structure and Confined Segmental Dynamics of PMMA Nanocomposite
Received date: 2014-05-01
Revised date: 2015-01-14
Online published: 2015-03-05
Supported by
国家自然科学基金资助项目(21174072)，高等学校仪器设备共建共享资助项目(CERS-1-61).
聚合物/无机纳米复合材料的微观结构和动力学决定了其宏观性能，阐明无机纳米材料对复合材料结构和动力学的影响，对认识材料结构-性能关系及设计新材料都具有重要意义．该文通过乳液聚合方法合成了聚甲基丙烯酸甲酯/锂藻土(PMMA/Laponite)纳米复合材料，采用1H MAS 和13C CPMAS、弛豫时间及13C 化学位移各向异性谱(SUPER)等多种固体NMR 技术，详细研究了无机纳米材料的界面改性及其对纳米复合材料的微观结构和动力学的影响．1H MAS 和13C CPMAS 实验表明，有机改性剂与锂藻土形成强的有机-无机界面相互作用，13C 纵向弛豫时间实验表明，PMMA 及其锂藻土纳米复合物均含有刚性和柔性两个组分，而纳米复合物中的聚合物链运动相对较低，特别是其中PMMA 的酯基分子运动明显受限．进一步的13C SUPER 实验表明，PMMA 酯基的化学位移各向异性在加入锂藻土后发生变化，预示酯基与锂藻土表面的羟基可能存在氢键作用而导致聚合物的链段运动进一步受限，上述纳米尺度受限效应提高了复合材料的玻璃化转变温度．
关键词： 固体核磁共振(solid-state NMR); 结构与动力学; 聚甲基丙烯酸甲酯(PMMA); 锂藻土; 纳米复合材料
刘 源 , 陈胜利 , 吴 强 , 陈铁红 , 孙平川 . 固体NMR 研究PMMA 纳米复合材料结构与受限链运动[J]. 波谱学杂志, 2015 , 32(1) : 23 -32 . DOI: 10.11938/cjmr20150103
Solid-state NMR techniques were used to study the structure and confined dynamics of poly-methyl methacrylate (PMMA)/laponite nanocomposite. 1H magic angle spinning (MAS) spectra and relaxation experiments indicate that organic modifiers (AIBA) interact strongly with laponite nano-sheets, and the structure of PMMA nanocomposite is homogenous at the scale of several nanometers. The results of 13C spin-lattice relaxation times (T1,C) experiments indicate that mobility of the PMMA segments, especially the carbonyl groups, in nanocomposite decreases under the confinement of laponite nano-sheets. 13C SUPER experiments further indicate that the incorporation of laponite induce a slight change of the CSA line shape of PMMA carbonyl groups.
Key words： solid-state NMR; structure; dynamics; PMMA; laponite; nanocomposite
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