Mechanical and Fracture Toughness Behavior of TPNR Nanocomposites

Abstract

Thermoplastic natural rubber (TPNR) nanocomposites containing organophilic layered silicates were prepared by melt blending method at 180°C using internal mixer (Haake 600P). The aim of this study is to determine the influence of the organoclay filler on the mechanical and fracture properties. In this study, two mixing methods were employed to incorporate filler into matrix, namely the direct (DM) and indirect (IDM) method. The mechanical properties of TPNR nanocomposites were studied using tensile, flexural, and impact tests. The tensile and flexural tests revealed that the optimum loading of organoclay was at 4 wt% using the indirect method of mixing. Plane stress fracture toughness of thermoplastic natural rubber (TPNR) nanocomposite was determined by the essential work of fracture (EWF) concept using tensile-loaded deeply double-edge notched (DDEN-T) specimens. The EWF measurements indicated that the specific essential work of fracture (we) decreased in the presence of nanoclay. Nevertheless, these TPNR nanocomposites met the basic requirement of the EWF concept of full ligament yielding, which was marked by a load drop in the force—displacement curves of the DDEN-T specimens.

Keywords

Nanocomposite thermoplastic elastomer organoclay fracture toughness mechanical properties.

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References

McNally, T. , McShane, P. , Nally, G.M. , Murphy, W.R. , Cook, M. and Miller, A. (2002). Rheology, Phase Morphology, Mechanical, Impact and Thermal Properties of Polypropylene/ Metallocene Catalysed Ethylene 1-Octene Copolymer Blends. Polymer, 43: 3785—3793.

Alexandra, M. and Dubois, P. (2000). Polymer Layered Silicate Nanocomposites: Preparation, properties, and Uses of New Class of Materials. Material Science and Engineering, 28: 1—63.

Akelah, A. , Salah El-Deen , N., Hiltner , Baer, A. and Moet, A. (1994). Organophilic Rubber-Montmorillonite Nanocomposites . Material Letters, 22: 97—102.

Hasegawa, N. , Kawasumi, M. , Kato, M. , Usuki, A. and Okada, A. (1998). Preparation and Mechanical Properties of PP-clay Hybrids Using a Maleic Anhydride Modified PP Oligomer . Journal of Applied Polymer Science, 67: 87—92.

Moore, D.R. , Pavan, A. and Williams, J.G. (2001). Fracture Mechanics Testing Methods for Polymers, Adhesives and Composites. ESIS Publication, 28, Elsevier, The Netherlands.

Yasue, K. , Katahira, S. , Yoshikawa, M. and Fujimoto, K. (2001). In: Pinnavaia, T.J and Beall, G.W. (ed) Polymer Clay Nanocomposites. John Willey and Sons, New York.

Kornmann, X. , Lindberg, H. and Berglund, L.A. (2001). Synthesis of Epoxy—Clay Nanocomposites: Influence of the Nature of the Clay on Structure, Polymer, 42: 1303—1310.

White, J.R. (1999). In: Karger-Kocsis, J. (ed.), Polypropylene: An A-Z Reference, Kluwer Academic Publisher, Dordrecht.

Karger Kocsis, J. , Barany, T. and Moskala, E.J. (2003). Plane Stress Fracture Toughness of Physically Aged Plasticized PETG as Assessed by the Essential Work of Fracture (EWF) Method. Polymer, 44: 5691—5699.

10.

Karger Kocsis, J. and Barany, T. (2002). Plane Stress Fracture Behavior of Syndiotactic Polypropylenes of Various Crystallinity as Assessed by the Essential Work of Fracture Method. Polymer Engineering and Science, 42: 1410—1419.

11.

Karger Kocsis, J. and Czigany, T. (2000). Strain Rate Dependence of the Work of Fracture Response of an Amorphous Poly(ethylene-naphthalate) (PEN) Film. Polymer Engineering and Science, 40: 1809—1815.

12.

Chow, W.S. , Ishak, Z.A. , Kocsis, J.K. , Apostolov, A.A. and Ishiaku, U.S. (2003). Compatibilizing Effect of Maleated Polypropylene on the Mechanical Properties and Morphology of Injection Moulded Polyamide 6/Polypropylene/Organoclay Nanocomposites. Polymer, 44: 7427—7440.

13.

Li, X. , Park, H.M. , Lee, J.O. and Ha, C.S. (2002). Effect of Blending Sequence on Microstructure and Properties of PBT/EVA-g-MAH/Organoclay Ternary Nanocomposites. Polymer Engineering and Science, 42: 2156—2164.

14.

Zhang, Q. , Fu, Q. , Jiang, L. and Lei, Y. (2000). Preparation and Properties of Polypropylene/ Montmorillonite Layered Nanocomposites. Polymer International, 49: 1561—1564.

15.

Lim, J.W. , Hassan, A. , Rahmat, A.R. and Wahit, M.U. (2006). Mechanical Behavior and Fracture Toughness Evaluation of Rubber Toughened Polypropylene Nanocomposites. Plastics, Rubber and Composites, 35(1): 1—10.

16.

Avella, M. , Cosco, S. , Di Lorenzo, M.L. , Di Pace, E. , Errico, M.E. and Gentile, G. (2006). Nucleation Activity of Nanosized CaCO3 on Crystallization of Isotatic Polypropylene, in Dependence on Crystal Modification, Particle Shape and Coating. European Polymer Journal, 42: 1548—1557.

17.

Surip, S.N. , Ahmad, S.H. , Rasid, R. and Hassan, N.A. (2005). Thermoplastic Natural Rubber Organoclay Filled nanocomposites — Part 1: Effect of Rubber Composition on the Tensile and Impact Properties. 5th National Symposium of Polymer Proceeding, Residence Hotel, Bangi, pp. 560—566.

18.

Vaia, R. and Giannelis, E. (1997). Polymer Melt Intercalation in Organically-Modified Layered Silicates: Model Predictions and Experiment. Macromol , 30: 8000—8009.

19.

Liu, X. and Wu, Q. (2001). PP/Clay Nanocomposites Prepared by Grafting Melt Intercalation. Polymer, 42: 10013—10019.

20.

Gatos, K.G. , Kameo, K. and Karger-Kocsis , J. (2007). On the Friction and Sliding Wear of Rubber/Layered Silicate Nanocomposites . Express Polymer Letters, 1: 27—31.

21.

Cai, L.F. , Mai, Y.L. , Rong, M.Z. , Ruan, W.H. and Zhang, M.Q. (2007). Interfacial Effects in Nano-silica/Polypropylene Composites Fabricated by In-situ Blowing. Express Polymer Letters, 1: 2—7