%0 Journal Article
%T Influence of CP time on Intermolecular Cross Polarization in the Composite of Poly(Ethylene Oxide) and Fullerene<br>交叉极化时间对分子间交叉极化的影响的研究
%A ZHANG Lei
%A YANG Guang
%A CHEN Qun
%A <br>张磊
%A 杨光
%A 陈群
%J 波谱学杂志
%D 2005
%I 
%X A composite of poly (ethylene oxide) (PEO) and fullerene (C_ 60) was prepared by lyophilization, and studied by high-resolution solid-state NMR spectroscopy. The 1H spin-spin relaxation time (T_2) of the composite was measured by 1H- 13C cross-polarization experiments with different contact times. It was found that the choice of contact time influence the results of intermolecular cross-polarization experiments, implying that extra care should be taken to select appropriate contact time when applying the intermolecular cross-polarization method to study the phase structures of composites. On the other hand, variation of contact time may provide a new dimension for experimental design and be used to gain information that is not obtainable in conventional experiments with fixed contact time. For example, the results of our experiments showed that in the PEO/C_ 60 composite not all the fullerene molecules are confined in the noncrystalline region of PEO, at least a portion of the C_ 60 molecules are located close to the crystalline region.
%K solid-state NMR
%K phase structure
%K cross polarization
%K C60/PEO composite<br>核磁共振
%K 相结构
%K 交叉极化
%K C60/PEO复合物
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=47EA7CFDDEBB28E0&jid=1A3C8C6E452BD1AF5A6B6B99BA3989C9&aid=4401FCDA9F7C237C&yid=2DD7160C83D0ACED&vid=BC12EA701C895178&iid=38B194292C032A66&sid=E2E0FBFE4D7EFB94&eid=4B1FFFA116F7AE3B&journal_id=1000-4556&journal_name=波谱学杂志&referenced_num=0&reference_num=8