http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/910 Fri, 24 May 2013 07:31:58 GMT 2013-05-24T07:31:58Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1999 Short Nylon Fibre Reinforced PP: Melt Rheology Abraham, Thomas N; George, K E Short fiber reinforced thermoplastics have generated much interest these days since fibrous materials tend to increase both mechanical and thermal properties, such as tensile strength, flexural strength, flexural modulus, heat deflection temperature, creep resistance, and some times impact strength of thermoplastics. If the matrix and reinforcement are both based on polymers the composite are recyclable. The rheological behavior of recyclable composites based on nylon fiber reinforced polypropylene (PP) is reported in this paper. The rheological behavior was evaluated both using a capillary rheometer and a torque rheometer. The study showed that the composite became pseudoplastic with fiber content and hence fiber addition did not affect processing adversely at higher shear rates. The torque rheometer data resembled that obtained from the capillary rheometer. The energy of mixing and activation energy of mixing also did not show much variation from that of PP alone. Mon, 01 Jan 2007 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1999 2007-01-01T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1998 Dynamic mechanical analysis of binary and ternary polymer blends based on nylon copolymer/EPDM rubber and EPM grafted maleic anhydride compatibilizer George, K E; Komalan, C; Kumar, P A S; Varughese, K T; Thomas, S The dynamic mechanical properties such as storage modulus, loss modulus and damping properties of blends of nylon copolymer (PA6,66) with ethylene propylene diene (EPDM) rubber was investigated with special reference to the effect of blend ratio and compatibilisation over a temperature range –100°C to 150°C at different frequencies. The effect of change in the composition of the polymer blends on tanδ was studied to understand the extent of polymer miscibility and damping characteristics. The loss tangent curve of the blends exhibited two transition peaks, corresponding to the glass transition temperature (Tg) of individual components indicating incompatibility of the blend systems. The morphology of the blends has been examined by using scanning electron microscopy. The Arrhenius relationship was used to calculate the activation energy for the glass transition of the blends. Finally, attempts have been made to compare the experimental data with theoretical models. Mon, 01 Jan 2007 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1998 2007-01-01T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1997 Silane Grafting of Polyethylenes George, K E; Isac, Sheela Reactive extrusion is an attractive means of polymer processing since the shaping and reaction take place in a single operation. In this paper we report the silane grafting of polyethylenes in a single screw extruder. The optimum conditions for silane grafting, viz. temperature, shear rate, silane and DCP concentrations, were determined on a torque rheometer and then actual extrusion was performed using these conditions. The study shows that an optimum low level of grafting/ crosslinking can be introduced into polyethylene during its extrusion for better mechanical behavior and=or thermal stability without affecting the processability. Sat, 01 Jan 2005 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1997 2005-01-01T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1996 Modification of Polypropylene/Glass Fiber Composites with Nanosilica George, K E; Jacob, Sinto; Suma, K K; Mendaz, Jude Martin; George, Abhilash Poly(propylene) (PP) reinforced with short glass fiber was modified with precipitated nanosilica (pnS) by melt mixing. The weight of the glass fiber was varied by keeping the pnS at optimum level. The properties of the composites were studied using universal testing machine, dynamic mechanic analyser (DMA), differential Scanning calorimetry (DSC) and thermo gravimetric analyser (TGA). The amount of the glass fiber required for a particular modulus could be reduced by the addition of nanosilica. Thu, 01 Jan 2009 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1996 2009-01-01T00:00:00Z