DETERMINATION OF 1-BUTENE DISTRIBUTION IN LLDPE BY DSC ANALYSIS AFTERTHERMAL FRACTIONATED CRYSTALLIZATION

The chemical composition distribution (CCD) of LLDPE (1-butene comonom er) has been studied by thermal analysis. After an opportune thermal t reatment of the polymers, thermal fractionated crystallization (TFC), the melting endotherms have been subdivided in areas with fixed temper ature ranges. The distribution of the endotherms in different areas ga ve a semiquantitative idea of the CCD. The comparison with thermal ris ing elution fractionation and C-13 NMR data of the whole polymers and fractions showed fairly good correlations. An approximate evaluation o f the average ethylene sequence length was also obtained.