Determination of orientation of the crystalline and amorphous phases in polyethylene by X-ray diffraction

Autor: Zigmond W. Wilchinsky
Rok vydání: 1968
Předmět:
Zdroj: Journal of Polymer Science Part A-2: Polymer Physics. 6:281-288
ISSN: 1542-9377
0449-2978
DOI: 10.1002/pol.1968.160060118
Popis: For polyethylene fibers, orientation parameters of the form 〈cos2 ϕ〉 were calculated from traces obtained with an x-ray diffractometer equipped with an orientation integrator. The angle ϕ is that which a crystal or molecular axis makes with the fiber axis. Traces over a continuous range of diffraction angle were obtained for (2/π)Iav, and also the weighted averages (2/π)Iav 〈cos2ϕ〉 and (2/π)Iav 〈sin2ϕ〉, where Iav is the intensity averaged over all orientations. The orientation for the crystal a, b, and c axes were determined from area measurements of the {110} and {200} lines, and the orientation parameter for the molecular axis in the amorphous phase was determined from area measurements of the amorphous halos. An undrawn fiber showed a slight a and c axis orientation along the fiber axis, and a slight transverse orientation of the b axis and the molecular axis. For a highly drawn fiber the orientation parameter for the c axis was 0.98 and for the molecular axis 0.65. The degree of crystallinity, measured from the (2/π)Iav versus 2θ traces, were 66.1% and 73.3% for the undrawn and drawn fiber, respectively.
Databáze: OpenAIRE
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