Chain structure comparison of two low density polyethylene resins fractionated by temperature rising elution fractionation and thermal fractionation

摘要: Two low-density polyethylene resins were fractionated into 11 fractions using the temperature rising elution fractionation technique. The of injection molding grade with similar densities but different melt indexes and mechanical properties. High-temperature gel permeation chromatography (HT-GPC), 13C-nuclear magnetic resonance (13C-NMR) spectroscopy, differential scanning calorimetry (DSC), successive self-nucleation/annealing (SSA) thermal employed to characterize original their fractions. Resin A had a higher molecular weight broader distribution than resin B did. highest contents found for 80 °C 75 °C B, respectively. In addition, weights at 2.14 × 105 1.42 × 105 g/mol, respectively, attained eluted 80 °C. According results 13C-NMR, total branching including short- long-chain branching, 3.63 mol% 4.89 mol%, DSC analysis revealed that crystallinity 3–10 was lower B. We noted presence approximately eight multiple melting peaks in sample from SSA. These indicated inhomogeneity chain. Lw Ln longer those Lastly, relationship between chain structure property also discussed.