STRUCTURE-PROPERTY RELATIONSHIPS OF COPOLYAMIDES .2. CRYSTAL-STRUCTURE OF DRAWN COPOLYAMIDE FILMS

The crystal structures of drawn copolyamides 6/6.6, 6/6.T, 6/6.1, 6/PXD.6, 6/MXD.6, and 6/MXD.I were examined by wide‐angle x‐ray diffraction. Copolyamide 6/6.6, which follows the inclusion model, shows only α‐characteristics at all the comonomer compositions examined (0–33.3 mol%). However, the other copolyamides, which follow either the partial‐inclusion or complete‐exclusion model, show γ‐characteristics more predominantly as the comonomer content increases. The interplanar spacing of the (200) planes, which corresponds to the hydrogen bond distance between antiparallel chains, remain constant, whereas the spacing of the (020) planes corresponding to the distance between hydrogen bonded sheets increases monotonically with increasing the comonomer content. It is also observed that both the crystal perfection index and the crystal thickness decrease as the comonomer content increases. Copyright © 1990 John Wiley & Sons, Inc.