A novel two-dimensional simulation method to analyze a wide-angle X-ray diffraction (WAXD) pattern is applied to crystal and crystallites of strain-induced crystallization (SIC) of un-vulcanized natural rubber (NR) and synthetic polyisoprene rubber (IR) at -50�C. Conventional one-dimensional profile analysis to determine crystallite information tends to be inaccurate due to very broad peak shapes that lead to difficult identifications of exact scattering angles of crystal peaks. This new two-dimensional approach leads to more precise values for integrated intensities and diffraction peaks, and can generate more accurate estimates for the crystallite size, percent crystallinity, as well as the preferred orientation. The unit cell dimensions of SIC were determined by calculation of scattering factors based on atomic coordinates and symmetry, and were compared with the observed data. It was found that the unit cell dimensions are the same in NR and IR, and do not change during extension. The crystallites' dimensions in NR and IR are almost the same at -50�C. The orientation of crystallites in NR is lower than in IR. The crystalline fraction increases with strain because of the increase in the number of crystallites. The different behavior of SIC in NR and IR seem to be caused by the pseudo-network of NR. 

Strain-induced crystal and crystallites structure of natural rubber and synthetic cis-1,4-polyisoprene by a new 2D wide angle X-ray diffraction simulation method

246th National Meeting (2013)

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