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For the first time we carried out a detailed Raman study of reactor blends of high-density ultrahigh molecular weight polyethylene (UHMW PE) with random ethylene/1-hexene copolymers (CEHs). The blends were produced by consecutive two-step polymerization in the presence of rac-Me 2 Si(Ind) 2 ZrCl 2 /methylaluminoxane catalyst. The blends differed significantly in the CEH content as well as in the 1-hexene content in the CEH. We revealed a strong dependence of the Raman spectra of the blends on their structure. We found out that an increase in both the CEH content in the blend and the 1-hexene content in the CEH causes a reduction of the blend crystallinity and the total content of trans-conformers, while an increase in the content of gauche-conformers is observed. To investigate the effect of molecular weight on the neat polyethylene (PE) structure and Raman spectrum, we analyzed three neat PE samples with molecular weights of 34 000, 750 000, and 1 000 000. In order to better understand general regularities in the spectra, Raman spectra of solid n-alkanes C 18 H 38 and C 36 H 74 were also studied.

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We carried out detailed Raman structural study ofmelt-mixed blends of linear low-densitypolyethylene (PE) and isotactic polypropylene (PP).The relative content of PE in the PE/PP blendsvaried from 13 to 75 %. We show that Ramanspectroscopy can be effectively used for aquantitative analysis of phase and conformationalcompositions of these blends. The changes in thesecompositions due to changing the content of theblend components are discussed. Also, we studied astructure of the amorphous phase of reactor blendsof PE with random ethylene/1-hexene copolymer(CEH).

In this work we present Raman study of random copolymers of ethylene and propylene with a number of α-olefins, and investigation of the relationships between the spectral characteristics of the Raman lines and the copolymer structural properties. For both the copolymers we observed rapid decrease in the crystallinity and conformational order as the content of the incorporated monomer increases.