摘要

Spherulites are important morphological forms in semicrystalline polymers. Polarized optical microscope (POM) is a powerful tool for observing the spherulite morphology of semicrystalline polymers and their composites, but it can not resolve spherulites with average size smaller than 5 pm and also not be used to study the opaque nanocomposites film samples. Atomic force microscopy (AFM) is an excellent tool for observing spherulites comparatively small in size and not restricted by the transparency of the samples. In this work, AFM was used to investigate the impact of Al nano- and microparticles on spherulitic textures, lamellar thickness, and thickness distribution of low density polyethylene (LDPE). It was found that the spherulitic texture was seriously disordered by the nanoparticles, and that the LDPE in nanocomposites was found only to have poorly developed spherulite structure. The incorporation of microparticles can facilitate the growth of the lamellae but decrease the size of the spherulites. Furthermore, the lamellar thickness and its distribution did not alter so much with the addition of nano- and microparticles. Wide-angle X-ray diffraction (WXRD) was used to determine the crystal structure of LDPE, and the results show that both Al nanoparticles and microparticles do not change the unit cell parameters.