| This investigation was undertaken to determine the effect that crystallinity had on the mechanical relaxation of a polymer above its glass transition temperature. It was proposed that above the glass transition temperature, the crystals exert a bracing action, acting like physical crosslinks limiting mobility of the amorphous regions of the polymer, affecting the slope of the relaxation spectra.;Five, commercially available thermoplastics, with varying ranges of crystallinity, were studied. Differential scanning calorimetry was used to determine the degree of crystallinity and dynamic mechanical rheology was used to obtain the relaxation spectra.;The results were mixed and this study was unable to confirm, on a broad range of materials, that as crystallinity increases, the slope of the relaxation spectra will decrease in a linear fashion. |
