Effects of Filler Incorporation Routes on Mechanical Properties of Low Density Polyethylene/Natural Rubber/Silica (LDPE/NR/Si) Composites

Abstract

Low density polyethylene (LDPE) and natural rubber (NR) filled silica composites were prepared by using internal mixer (Brabender) at 150°C and 50 rpm for 10 minutes. Silica was incorporated into polymer matrix by three mixing routes by using Brabender. In mixing I, filler was added into LDPE/NR blend. In mixing II, filler was added prior to LDPE, which was further compounded with NR. In mixing III, filled was pre-dispersed into NR using two-roll mill, after that the compound is blended with LDPE. The effects of filler incorporation routes on the morphological and tensile properties of prepared composites were studied. Observation from SEM result showed that silica tended to localize in NR phase than LDPE phase in the composite. In addition, silica filled LDPE/NR composite exhibited the highest tensile strength in mixing II and lowest in mixing III. Tensile fracture surface of the composites showed typical morphology of LDPE and NR phase depending on mixing methods. KEYWORDS: LDPE/NR, silica, mixing order, tensile properties, morphology