ABSTRACT In this paper, a comparative study on the fracture toughness of woven glass fibre reinforced polypropylene, chopped glass fibre reinforced polypropylene and nanoclay filled polypropylene composites is presented. Nanoclays (Cloisite 15A) of 1 wt. % to 5 wt. % were filled in polypropylene (PP) matrix and they were subjected to fracture toughness stu-dies. The specimen with 5 wt. % nanoclay showed 1.75 times and 3 times improvement in critical stress intensity factor (KIC) and strain energy release rate (GIC), respectively, over virgin PP. On the other hand, 3 wt. % nanoclay PP composites showed superior crack containment properties. These structural changes of composite specimens were examined using Transmission Electron Microscopy (TEM) and X-ray diffraction (XRD) methods. It showed that exfoli-ated nanocomposite structures were formed up to 3 wt. % nanoclay, whereas, intercalated nanocomposite structures formed above 3 wt. % nanoclay in the PP matrix. Furthermore, the woven fibre reinforced PP composites demonstrated superior crack resistant properties than that of clay filled nanocomposites and chopped fibre PP composites. However, KIC and GIC values for woven fibre composites were lesser than that of chopped fibre composites. Moreover, KIC and GIC values for both nanoclay filled PP composites and woven fibre composites are comparable even though the clay filled PP demonstrated catastrophic failure. Also, the crack propagation rate of PP-nanoclay composites is comparable to that of chopped fibre composites.
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nullA. Ramsaroop, K. Kanny and T. Mohan, "Fracture Toughness Studies of Polypropylene- Clay Nanocomposites and Glass Fibre Reinfoerced Polypropylene Composites," Materials Sciences and Applications, Vol. 1 No. 5, 2010, pp. 301-309. doi: 10.4236/msa.2010.15044.
 J. Karger-Kocsis, T. Harmia and T. Czigany, “Comparison of the Fracture and Failure Behavior of Polypropylene Composites Reinforced by Long Glass Fibers and by Glass Mats,” Compo-sites Science and Technology, Vol. 54, No. 3, 1995, pp. 287-298.
 J. Liakus, B. Wang, R. Cipra and T. Siegmund, “Processing–Microstructure-Property Predictions for Short Fiber Reinforced Composite Structures Based on a Spray Deposition Process,” Composite Structures, Vol. 61, No. 4, 2003, pp. 363-374.
 S. W. Jung, S. Y. Kim, H. W. Nam and K. S. Han, “Measurements of Fiber Orientation and Elastic-Modulus Analysis in Short-Fiber-Reinforced Composites,” Composites Science and Technology, Vol. 61, No. 1, 2001, pp. 107-116.
 H.-Y. Cheung, M.-P. Ho, K.-T. Lau, F. Cardona and D. Hui, “Natural Fibre-Reinforced Composites for Bioen-gineering and Environmental Engineering Applications,” Composites Part B: Engineering, Vol. 40, No. 7, 2009, pp. 655-663.
 G. Ben-Dor, A. Dubinsky and T. Elperin, “An Engineering Approach to Shape Optimization of Impactors against Fiber-Reinforced Plastic Laminates,” Composites Part B: Engineering, Vol. 40, No. 3, 2009, pp. 181-188.
 M. Bhattacharya and A. K. Bhowmick, “Polymer–Filler Interaction in Nanocomposites: New Interface Area Function to Investigate Swelling Behavior and Young’s Modulus,” Polymer, Vol. 49, No. 22, 2008, pp. 4808- 4818.
 T. A. Rajesh and D. Kumar, “Recent Progress in the Development of Nano-Structured Conducting Polymers/ Nanocomposites for Sensor Applica-tions,” Sensors and Actuators B: Chemical, Vol. 136, No. 1, 2009, pp. 275-286.
 L. Kumari, T. Zhang, G. H. Du, W. Z. Li, Q. W. Wang, A. Datye and K. H. Wu, “Thermal Properties of CNT- Alumina Nanocomposites,” Composites Science and Technology, Vol. 68, No. 9, 2008, pp. 2178-2183.
 D. Sikdar, D. R. Katti, K. S. Katti and R. Bhowmik, “Insight into Molecular Interactions between Constituents in Polymer Clay Nanocomposites,” Polymer, Vol. 47, No. 14, 2006, pp. 5196-5205.
 B. Xu, Q. Zheng, Y. H. Song and Y. G. Shangguan, “Calculating Barrier Properties of Polymer/Clay Nanocomposites: Effects of Clay Layers,” Polymer, Vol. 47, No. 8, 2006, pp. 2904-2910.
 P. Meneghetti and S. Qutubuddin, “Synthesis, Thermal Properties and Applications of Polymer-Clay Nanocomposites,” Thermochimica Acta, Vol. 442, No. 1-2, 2006, pp. 74-77.
 G. Scocchi, P. Posocco, A. Danani, S. Pricl and M. Fermeglia, “To the Nanoscale, and Beyond: Multiscale Molecular Modeling of Polymer-Clay Na-nocomposites,” Fluid Phase Equilibria, Vol. 261, No. 1-2, 2007, pp. 366-374.
 J. G. Zhang, D. D. Jiang and C. A. Wilkie, “Polyethylene and Polypropylene Nanocomposites Based upon an Oligomerically Modified Clay,” Thermochimica Acta, Vol. 430, No. 1-2, 2005, pp. 107-113.
 Q. Yuan, S. Awate and R. D. K. Misra, “Nonisothermal Crystallization Behavior of Polypropylene–Clay Nanocomposites,” European Polymer Journal, Vol. 42, No. 9, 2006, pp. 1994-2003.
 D. Garcia-Lopez, O. Picazo, J. C. Merino and J. M. Pastor, “Poly-propylene–Clay Nanocomposites: Effect of Compatibilizing Agents on Clay Dispersion,” European Polymer Journal, Vol. 39, No. 5, 2003, pp. 945-950.
 Y. Dong and D. Bhattacha-ryya, “Mapping the Real Micro/Nanostructures for the Prediction of Elastic Moduli of Polypropylene/Clay Nanocomposites,” Polymer, Vol. 51, No. 3, 2010, pp. 816-824.
 L. Raka, G. Bogoeva-Gaceva, K. B. Lu and J. Loos, “Characterization of Latex-Based Isotactic Polypropylene/Clay Nanocomposites,” Polymer, Vol. 50, No. 15, 2009, pp. 3739-3746.
 L. Cauvin, D. Kondo, M. Brieu and N. Bhatnagar, “Mechanical Properties of Polypropylene Layered Silicate Nanocomposites: Characterization and Micro-Macro Modelling,” Polymer Testing, Vol. 29, No. 2, 2010, pp. 245-250.
 N. A. Siddiqui, R. S. C. Woo, J.-K. Kim, C. C. K. Leung and A. Munir, “Mode I Interlaminar Fracture Behavior and Mechanical Properties of CFRPs with Nanoclay-Filled Epoxy Matrix,” Composites Part A: Applied Science and Manufacturing, Vol. 38, No. 2, 2007, pp. 449-460.
 B. Cotterell, J. Y. H. Chia and K. Hbaieb, “Fracture Mechanisms and Fracture Toughness in Semicrys-talline Polymer Nanocomposites,” Engineering Fracture Me-chanics, Vol. 74, No. 7, 2007, pp. 1054-1078.
 L. Y. Sun, R. F. Gibson, F. Gordaninejad and J. Suhr, “Energy Absorption Capability of Nanocomposites: A Review,” Composites Science and Technology, Vol. 69, No. 14, 2009, pp. 2392-2409.
 W. P. Lui, S. V. Hoa and M. Pugh, “Fracture Toughness and Water Uptake of High-Performance Epoxy/Nanoclay Nanocomposites,” Composites Science and Technology, Vol. 65, No. 15-16, 2005, pp. 2364- 2373.
 M. N. Bureau, M.-T. T.-T. and F. Perrin-Sarazin, “Essential Work of Fracture and Failure Mechanisms of Polypropylene-Clay Nanocomposites,” Engineering Fracture Mechanics, Vol. 73, No, 16, 2006, pp. 2360- 2374.
 S. C. Tjong and S. P. Bao, “Fracture Toughness of High Density Polyethy-lene/SEBS-g-MA/Montomorrilonite Nanocomposites,” Com-posites Science and Technology, Vol. 67, No. 2, 2007, pp. 314-323.
 Y. Xu and S. Van Hoa, “Mechanical Properties of Carbon Fibre Reinforced Epoxy/Clay Nanocomposites,” Composites Science and Technology, Vol. 68, No. 3-4, 2008, pp. 854-861.
 V. K. Moodley and K. Kanny, “Characterization of Polypropylene Nanocomposite Structures,” Journal of Engineering Materials and Technology, Vol. 40, 2007, pp. 1-8.
 K. Lau, M. Ho, C. Lam, H. L. Ng and D. Hui, “Me-chanical Properties of Epoxy-Based Composites Using Nanoc-lays,” Composites Structures, Vol. 75, No. 1-4, 2006, pp. 415-421.