JMS_V3_N1_RP4 Krupashankara M.S. Shreevathsa Kishore Kumar Shet B.K. Sridhara Journal on Material Science 2347–615X 3 1 23 30 Thermoplastics, Composites, Multiwalled Carbon Nanotubes, Tensile Properties, Mathematical Models, Effective Length, Effective l/d Ratio Multiwalled Carbon Nanotubes (MWCNT) were melt-blended into ABS matrix using twin screw extrusion process. The percentage of MWCNT was varied from 0 to 15%. Tensile properties were measured using ASTM D638-10. At 10 wt.% these composites showed the highest modulus values of ~1600 MPa, which is nearly 40% higher compared to pure ABS. The ultimate tensile strength values of 15 wt.% MWCNT-ABS composite was 25% more than pure ABS. The failure strain of MWCNT-ABS composites drops linearly to 4% for a reinforcement of 15 wt.% MWCNT in ABS matrix. FESEM (Field Emission Scanning Electron Microscopy) examination of the specimens revealed a combination phase separated and exfoliated structure with polymer matrix over MWCNT. The experimental results were compared with theoretical iso-stress, iso-strain & Halpin-Tsai models. The experimental results lie between the theoretical values determined using the iso-stress and Halpin-Tsai models only if the 'effective l/d' ratio is considered in case of MWCNT. Microscopic analysis of the composites revealed the 'effective l/d' ratio to be in the range of 1 to 2.5. The experimental results of the ultimate strength values match well with the modified rule of mixture model, with strength efficiency and effective length factors. This paper has attempted to introduce two new factors 'effective l/d ratio' and 'effective length' to co-relate experimental and theoretical data. April - June 2015 Copyright © 2015 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=3368