| For a long time polymer scientists have been interested in measuring crystallite size of polyethylene (PE) single crystals and melt-crystallized PE. Since crystallite sizes are related to the strength and morphology of the polymer crystals, the rationale behind this work has been to obtain a better understanding of crystallite sizes with respect to the morphology of the crystals.; X-ray line broadening experiments on dried and wet PE single crystals indicate the following: (1) crystallite size in dried PE single crystals can be explained on the basis of "mosaic blocks" whereas, crystallite size in wet PE single crystals can be explained based on geometrical limitations or the "upper limit" model.; X-ray line broadening measurements of isothermally melt-crystallized PE samples indicate that crystallite sizes in these samples could be explained based by the mosaic block model or distortion in lamellae. Moreover, crystallite sizes and paracrystalline distortion values of these samples are independent of crystallization temperature (T(,c)) and/or crystallization time. |
