Two-Dimensional Wide-Angle X-Ray Diffraction Simulation Study On Strain-Induced Crystallization and Temperature-Induced Crystallization of Un-Vulcanized Natural and Synthetic Rubber

New insights into the strain-induced crystallization (SIC) and temperature-induced crystallization (TIC) of un-vulcanized natural rubber (NR) and synthetic polyisoprene rubber (IR) have been obtained using a novel two-dimensional simulation method that calculates a wide-angle X-ray diffraction (WAXD) pattern. 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 WAXD patterns of strain-induced crystallization (SIC) and temperature-induced crystallization (TIC) of un-vulcanized NR and IR were analyzed in this study. The calculated WAXD patterns from simulations were compared with the experimental obtained WAXD patterns and demonstrated an excellent fit. Lateral crystallite sizes, crystallinity fractions, and crystallite orientations were calculated from the simulated WAXD patterns.