Effect of blend composition on abrasive wear of red mud filled PP/LDPE blends

Effect of blend composition on abrasive wear behaviour has been studied for red mud (RM) particulate filled blends of isotactic polypropylene (PP) and sernicrystalline low density polyethylene (LDPE) by using two body abrasion tester. Wear rate has been correlated with the composition and structure of the studied systems. Wear rate decreased with the increase of PP content in those blend compositions where PP form the matrix, whereas reverse was observed in case of compositions in which LDPE forms matrix. Mechanism of this behaviour has been explained on the basis of X-ray diffraction studies and interaction amongst the constituents of composites. Chemical resistance, high damping properties for low noise emission, ability of dry sliding etc.!" makes polymers and their blends suitable for wear applications. The problem associated with polymers lies in their low operating temperature due to which strength goes down owing of creep which occurs under a load. In such cases particulate filled polymers provide a high load capacity 1 • Moreover addition of filler into polymers improves flexural modulus, dimensional stability, heat deflection temperature etc?". Fillers reduce wear by modifying the counterphase surface 10 by changing crystalline structure of polymer" or by inhibiting the large scale destruction of banded structure" . In recent years several studies have been reportedlQ-ls to understand the wear behaviour of some selected polymeric systems such as teflon based materials but less attention has been focused on polyolefin blends. These blends have drawn attention of researchers due to the possibilities of improving the performance of materials as well as their recycleability. Mechanical, rheological and morphological properties of red mud particulate filled isotactic polypropylene (PP) / low density polyethylene (LDPE) blends have been reported recently'<". Red mud is a solid waste material produced by the alumina industries following the Bayer's process. Several studies related to disposal, characterization and utilization ofred mud have been reviewed". It has been used as filler'"?' material with several polymers and blends to improve their mechanical, thermal and rheological properties. Effect of addition of red mud particles in PPILDPE blend was studied". Blend ratio ofPPILDPE was fixed at 1.0 and loading of redmud was varied. It was observed that at low concentration of redmud, abrasive wear loss of composites increased with redmud loading. The wear loss however, showed a decreasing trend after a critical loading of redmud in the composites. This improvement was attributed to the increased number of RM particles available on the surface to resist abrasion of polymer. In present paper redmud loading has been kept constant and blend ratio of PPILDPE has been varied to study the effect of matrix composition on wear properties.