Abstract: Long chain branched polypropylene (LBPP) were prepared via reactive extrusion in the presence of pentaerythritol triacrylate (PETA) and a peroxide. The rheology and thermal properties of linear PP and modified LBPP were evaluated using rotational rheometer and differential scanning calorimetric (DSC). Moreover, the influence of the type of peroxide on the properties and branching degree of LBPP were also evaluated. LBPP exhibited a higher G’ at low frequency, lower Tan δ at low frequency, higher zero shear viscosity, and stronger shear shinning, which constituted the features of long branching. DSC determination showed that the crystallization temperature of LBPP was higher than that of linear PP. In addition, it was found that the type of peroxide did not significantly affect the thermal and rheological properties and branching degree of modified LBPP.

Key words: long chain branching polypropylene, rheology, thermal properties, reactive extrusion