Samples of polycarbonate (PC) before and after remelting and isothermal solidification treatment were characterized by wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS), microhardness, and stretching calorimetry techniques. Both PC samples could be regarded as structurally identical (X-ray amorphous); however, the isothermally solidified sample exhibited higher microhardness and Young's modulus, as well as a lower linear expansion coefficient and greatly reduced breaking strain. These results are attributed to the overlap of a network of ultramicrocrystals on the original entanglement network in the reference (untreated) PC sample.

This work was supported by the NATO Linkage Grant HTECH.LG 960084 and by the DGICYT, Spain (grant PB94-0049). Thanks are due to the Ministerio de Educacion y Cultura, Spain, for a sabbatical grant to V. P. P.

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