Effect of process parameters on the properties of nanocomposites prepared by melt compounding in a twin screw extruder

In this work the effect of the process parameters, e.g. screw speed, feed rate, type of flow, etc., on the morphological and thermal properties of nanocomposites prepared by melt compounding was investigated. Compounding took place in a twin screw extruder with a screw diameter of 24 mm and a length-to-diameter ratio (L/D) of 40. Low density polyethylene (LDPE)/compatibilizer/organoclay nanocomposites were prepared via direct melt intercalation in a co-rotating twin screw extruder by varying the composition and process conditions. The nanocomposites morphology was analyzed by X-ray diffraction (XRD) and by transmission electron microscopy (TEM). In order to evaluate the degree of processability of polymeric nanocomposites, the steady shear response at high shear flow conditions was investigated with an on-line capillary rheometer. In particular the attention was focused on the level of dispersion which was reached and on possible preferential orientation of high aspect ratio nanofillers that could be induced by properly modulating the processing conditions.