Rotationally molded polyethylene: Structural characterization by x-ray andmicrohardness measurements

Rotationally molded polyethylene (PE) blended in two ways (turbo blending a nd extrusion) with nucleating and nonnucleating pigments is structurally ch aracterized by wide- and small-angle x-ray scattering (WAXS and SAXS, respe ctively), DSC and microhardness measurements. Morphological observations ar e performed by polarized. light microscopy. The melting temperature and the degree of crystallinity (from both DSC and WAXS) remain essentially consta nt regardless of sample preparation and type of pigment. The same holds for the crystal sizes from WAXS and the lamella thickness from SAXS. Only the values of microhardness depend on the type of pigment, increasing about 10% when a nucleating type is used. The almost constant values of these proper ties, contrasting to the spherulitic morphology, are very favorable for cry stallization. As a consequence, optimal crystalline structure is achieved, which masks significantly the effect of pigments and blending conditions on the crystallization behavior of polyethylene. (C) 2001 John Wiley & Sons, Inc. Adv Polym Techn 20: 116-124, 2001.