Melt rheological properties of aluminaÀfilled isotactic polypropylene composites have been estimated at 0À22.2 vol% alumina at 493 K. The composite melts obeyed power law in shear stress-shear rate relations and were shear thinning. Apparent melt viscosity decreased initially up to 5.8% by volume alumina and increased with further increase in filler concentration. Melt elasticity decreased marginally upto f F ¼ 5.8% whereas the data increased upon further increase in alumina content. Surface modification of alumina particles by a titanate coupling agent LICA 38 brought about interesting modification of the rheological properties through a plasticizing=lubricating function and=or blocking of the surface groups of Al 2 O 3 particles.

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