A SMALL-ANGLE AND WIDE-ANGLE X-RAY-SCATTERING STUDY OF 1-BUTENE LLDPEOBTAINED BY METALLOCENE AND ZIEGLER-NATTA CATALYSIS

Four samples were examined of 1-butene linear low density polyethylene , having comparable molecular weight and different comonomer content. Two of them were obtained by using metallocene catalysts and the other ones were commercial products from Ziegler-Natta catalysis. An analys is was carried out by small- and wide-angle X-ray scattering in order to obtain information on the distribution of the lamellar thicknesses, the crystallinity of the samples and the expansion of the crystalline unit cell, as a function of the comonomer content. A narrower distrib ution of the lamellar thicknesses was detected in the samples obtained by homogeneous catalysis. Some evidence is reported on the exclusion of chain branchings from the crystalline regions. (C) 1997 Elsevier Sc ience Ltd.