The structural change of natural rubber with mastication was examined by 'H pulsed NMR. Although the conventional pulsed NMR method gives the spin-spin relaxation time (T2), the fraction (F) and the Weibull index (W), the method has subjectivity and ambiguity in the separation of components. By applying the Gaussian expansion to the spin-spin relaxation decay, the relaxation spectrum was obtained as a relationship of relaxation time and component. The decay curve was reconstructed from relaxation spectrum in good agreement with the measured decay. The main peak of the relaxation spectrum, which corresponds to entangled network chains, became broad with the decrease of molecular weight caused by mastication. Since the broadening was observed only in the longer side of relaxation time, the broadening is considered to correspond with the increase of the non-network chains and the loose entanglements. Expansion by Gaussian or other series is one of the effective measures to avoid subjectivity in pulsed NMR analysis, and also gives more information in combination with conventional parameters　(T2,　F, and W).

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The macroscopic magnetization M(t) obtained from pulsed-NMR measurement is data with very much amount of information about molecular structure, adegree of crystallinity, entanglement, etc. So, analysis is very complicated. Usually FID signal was expressed as the sum of some distribution functions with different relaxationtime. For this reason, the information on macroscopic magnetization M(t) was not fully utilized. By carrying out numerical differentiation of FID signal, the author made the program which calculates a relaxation spectrum. Compare dwith T2 conventional relaxation time, the amount of information acquired increased overwhelmingly. However, the analysis remained qualitatively. Then, we separated into some peaks by assuming this relaxation spectrum to be an aggregate of a density function. The program of multi-peak fitting was created. By using this method, multi-peak analysis of styrene block polymer was performed. Moreover, the relaxation spectrum could be disassembled into 11 peaks by enlarging measurement density in polystyrene. The effect of annealing could be caught quantitatively. However, showing clearly which peak belongs to which proton must wait for future research. We believe that low resolution 1H-Pulsed NMR will be widely utilized by quantification by multi-peak revolution of this relaxation spectrum from now on.

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Poly (vinyl alcohol)(PVA)/montmorillonite (MMT)nanocomposite was prepared simply by castingaqueous suspension. X-ray diffraction, scanning electron microscopy (SEM) and tensile test were used to investigate the structure and the mechanical properties of the nanocomposite. In the nanocomposite, MMT layers were found to be successfully exfoliated and nano dispersed in the PVA matrix. The mechanical properties of the nanocomposite increased by the incorporation of only a small amount (5%W/W) of MMT. "X-ray diffraction method" was applied to investigate the stress transfer system in the nanocomposite from a microscopic point of view. The stress on MMT is found to be incredibly high compared with that applied on the whole composite; the outstanding stress transfer in the nanocomposite was revealed. Therefore the high mechanical properties of the PVA/MMTnanocomposite could be attributed to this excellent stress transfer system in the nanocomposite.

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