A STUDY OF THE LAMELLAR THICKNESS DISTRIBUTION IN 1-BUTENE, 4-METHYL-1-PENTENE AND 1-HEXENE LLDPE BY SMALL AND WIDE-ANGLE X-RAY-SCATTERING AND TRANSMISSION MICROSCOPY

Three samples were examined of commercial linear low-density polyethyl ene, containing different comonomers (I-butene, 4-methyl-1-pentene and l-hexene) and having comparable molecular weight and branching amount . An analysis was carried out by transmission electron microscopy and small- and wide-angle X-ray scattering. The thicknesses were determine d of the polymer lamellae, as well as their distributions and the morp hology of the crystalline phase. Moreover, small-angle X-ray scatterin g experimental spectra were analyzed by a fit with the profiles calcul ated from some theoretical distribution models of the lamellar thickne ss. The mathematical evaluation of small angle X-ray scattering patter ns and the analysis by transmission electron microscopy have provided crystallinity values which were compared with those obtained by wide a ngle X-ray scattering in order to obtain information on the organizati on in lamellar stacks. The fitting method has also provided lamellar t hickness values comparable to the transmission electron microscopy dat a. (C) 1998 Elsevier Science Ltd. All rights reserved.