| Abstrakt: |
Summary A variety of techniques, comprising degradation, low angle X-ray diffraction, and measures of crystallinity, have been applied to polyethylene crystals showing crystallographic contact between constituent layers. The results are analysed in the light of the model proposed in the preceding communication, and defined more concretely in the present paper. This model requires that the short molecules-one to three times the layer thickness in length-which largely constitute these crystals should have their ends at the lamellar surfaces. As a consequence, in the presence of the finite molecular weight spread, these surfaces will have to the rough owing to uneven lengths of the lamellar traverses. This roughness enables intermeshing of layers, which constitutes the observed crystallographic contact. Infra red experiments verify that the ends are at the surfaces; G. P. C. analysis of nitric acid degraded material measures the surface roughness as detected by fluctuations in the depths of the folds. |
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