Comparative analysis of reactive extrusion of LDPE and LLDPE

Grafting of polyethylenes is an important method used in the modification of polyolefins with functional groups. Nevertheless, few systematic studies have been conducted regarding this type of reactions and the interdependent variables are not yet accurately established. In this investigation, the grafting of two commercial polyethylenes, low-density polyethylene and linear low-density polyethylene with diethyl maleate was carried out in a corotating twin-screw extruder at different extrusion conditions. In order to establish the interdependence of the extrusion conditions employed, a combined experimental and simplified one-dimensional, non-isothermal model was implemented in the study of flow in the elements of the screw-extruder. The effects of the grafting degree and the processing conditions employed in the preparation of the functionalized materials on their shear and elongational viscosities at high shear rates, and on their thermal and tensile properties were studied.