Chinese Journal of Magnetic Resonance ›› 2010, Vol. 27 ›› Issue (4): 597-608.

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Chemical Shift Anisotropy of Polypropylenes: Theoretical Calculation and Experimental Results from Solid-State NMR Experiments

 XU Lu1, LI Bao-Hui1, SUN Ping-Chuan2*   

  1. 1. School of Physics, Nankai University, Tianjin 300071, China;
    2. Key Laboratory of Functional Polymer Materials, Ministry of Education, Nankai University, Tianjin 300071, China
  • Received:2010-02-09 Revised:2010-04-22 Online:2010-12-05 Published:2010-12-05
  • Supported by:

    国家杰出青年科学基金资助项目(20825416).

Abstract:

Chemical shift isotropy and anisotropy of isotactic and syndiotactic polypropylene (denoted as iPP and sPP, respectively) were predicted by quantum chemical calculation. 13C chemical shift anisotropy (CSA) powder patterns of iPP were successfully determined with the separation of undistorted powder patterns by effortless recoupling (SUPER) experiments. It was found that the results from quantum chemical calculation are in good accordance with that from solid-state NMR experiments. These results indicate that the combination of quantum chemical calculation and solid-state NMR experiment is a powerful tool in elucidating the microstructure of polymers. The two important solid-state NMR techniques for obtaining 13C CSA powder pattern, SUPER and recoupling of anisotropy information (RAI), were compared, with their advantages and disadvantages discussed using methylmalonic acid as a sample compound.

Key words: quantum chemical calculation, solid-state NMR, chemical shift, polymer, polypropylene

CLC Number: