Precise Analyzes of Low Frequency Motions of Polymers by Advanced Solid-State NMR Spectroscopy

通过先进的固态核磁共振波谱精确分析聚合物的低频运动

• 批准号: 08455453
• 负责人: HORII Fumitaka
• 金额: $ 4.48万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08455453/
• 关键词: Solid-State NMR; Glassy polymera; Molecular Motion; Two-Dimensional NMR; Chemical Shift Anisotropy; Relaxation Processes; 定速分子運動; フェノキシ樹脂; ポリ(4-メチルペンテン-1); 多次元固体NMR; 双極子スペクトル; Switching Angle Sample Spinning法; 超低速Magic Angle Spinning法

In order to clarify the low frequency motion of polymers at awide rangeof temperature including the glass transition region by advanced solid-state NMR spectroscpy, we have developed one-and two-dimensional NMR tochniques and established methods of the spectral analyzes by using phenoxy resins with a lower T_g as a model polymer.In CP/MAS ^<13>C NMR spectra, it has been found that the gamma-relaxation process can observed as changes in spectra from doublets to singlets for the phenylene CH carbons. The detailed analysis of this process by the two-site exchange model has determined the exchange frequencies at different temperatures. In contrast, the alpha-relaxation process is recognized as remarkable motional broadening/motional narrowing for most of resonance lines, leading to the determination of frequencies of the molecular motions associated with these changes in linewidth. Moreover, new analytical methods of two-dimensional exchange ^<13>C CP/MAS spectra in the alpha-and gamma-rel … More axation processes have been proposed to characterize slower molecular motions that are not detectable by one-dimensional methods above described.To further determine the modes of molecular motions in the alpha-and gamma-relaxation processes, we have developed two-dimensional switching angle sample spinning (SASS) or two-dimensional magic angle turning (MAT) method for the precise measurements of chemical shift anisotropy (CSA) of the phenylene carbons. The CSA spectra thus obtained have been successfully analyzed in terms of the 2-site of 8-site exchange model for the gamma-or alpha-relaxation process, respectively. As for the aliphatic CH and CH_2 carbons, we have tried to measure spectra reflecting the ^1H-^<13>C dipolar interaction by using two-dimensional SASS method. Unfortunately, such measurements have been found to be unsuccessful because the RF power is not enough for the two-dimensional measurements. Since the improvement of tha SASS prove has been very recently performed, we believe that the analyzing method for the ^1H-^<13>C dipolar spectra will be also established in near future. Less

为了用先进的固体核磁共振技术解释聚合物在包括玻璃化转变区在内的宽温度范围内的低频运动，我们发展了一维和二维的核磁共振技术，并建立了以低T_g的酚氧基树脂为模型聚合物的光谱分析方法。在CP/MAS^&lt；13&gt；C核磁共振谱中，发现苯基碳的伽马弛豫过程可以观察到从双峰到单峰的变化。利用双位交换模型对这一过程进行了详细的分析，确定了不同温度下的交换频率。相反，对于大多数共振线来说，α松弛过程被认为是显著的运动展宽/运动收窄，导致了与这些线宽变化相关的分子运动频率的确定。此外，α和伽马射线…中二维交换谱的新分析方法为了进一步确定分子在α松弛和伽马松弛过程中的运动模式，我们发展了二维开关角样品旋转(SASS)或二维幻角翻转(MAT)方法，用于精确测量苯碳的化学位移各向异性(CSA)。所获得的CSA谱分别用伽马和α弛豫过程的2位和8位交换模型进行了分析。对于脂肪族CH和CH_2碳，我们尝试用二维SASS方法测量了反映^1H-^&lt；13&gt；C偶极相互作用的光谱。不幸的是，这种测量被发现是不成功的，因为射频功率不足以进行二维测量。由于SASS证明的改进是最近进行的，我们相信在不久的将来也将建立分析^1H-^&lt；13&gt；C偶极谱的方法。较少

项目成果

Kazuhiro Kuwabara: "Solid-State ^<13>CNMR Analyses of the Crystalline-Noncrystalline Structure for Metallocene-Catalyzed Linear Low-Density Polyethylene" Macromolecules. 30巻24号. 7516-7521 (1997)

Kazuhiro Kuwabara：“茂金属催化的线性低密度聚乙烯的结晶-非结晶结构的固态 13 CNMR 分析”，第 30 卷，第 24 期。7516-7521 (1997)。

Kazuhiro Kuwabara: "Solid-State ^<13>C NMR Analyses of the Crystalline-Noncrystalline Structure for Metallocene-Catalyzed Linear Low-Density Polyethylene" Macromolecules. 30巻24号. 7516-7521 (1997)

Kazuhiro Kuwabara：“茂金属催化的线性低密度聚乙烯的结晶-非结晶结构的固态13 C NMR分析”，第30卷，第24期。7516-7521(1997)。

K.Kuwabara, H.Kaji, F.Horii, D.C.Bassett, R.olley: "Solid-State 13C NMR Analyzes of the Crystalline-Noncrystalline Structure for Metallocene-Catalyzed Linear Low-Density Polyethylene" Macromolecules. 30, No.24. 7516-7521 (1997)

K.Kuwabara、H.Kaji、F.Horii、D.C.Bassett、R.olley：“茂金属催化线性低密度聚乙烯结晶-非结晶结构的固态 13C NMR 分析”。