Blends of single-site linear and branched polyethylene. I. Thermal characterisation

Blends of a low-molecular-weight linear polyethylene and several different ethylene–hexene copolymers are investigated using differential scanning calorimetry and transmission electron microscopy. All blend components are based on single-site catalysts. For cooling rates higher than 1°C/min, reorganisation effects are generally present, making the interpretation of the blends less clear. The reorganisation effects are found to be dependent of the amount of comonomer in the branched blend component, the compositions of the blends and the cooling and heating rates applied. For a low content of the linear blend component, even 1.8 mol% comonomer content in the branched blend component is sufficient to create two crystal populations during crystallisation. For higher amounts of the linear blend component 2.5 mol% comonomer will result in two crystal populations.