Various alkyl ammonium cations were ionically exchanged with the sodium cations of montmorillonites with two different cation exchange capacities (CECs). The organo-montmorillonites were compounded with polypropylene (PP) and the effect of filler-matrix interactions on the intercalation-exfoliation behavior and the mechanical properties of the composites were investigated. With increasing the chain packing density, an increase in the d-spacing was observed and for the same cation, the d-spacing of the OMMT was higher for the higher CEC clay. Covering the surface with molecules of higher cross-sectional area led to large basal plane spacing which was helpful in achieving the partial delamination of the filler in the PP matrix even without the use of conventional compatibilizers. The modulus of PP organo-montmorillonite composites was significantly enhanced, but the other tensile properties decreased indicating the increased brittleness and lack of stronger attraction forces at interface. Augmenting the filler volume fraction also led to a significant increase in the stiffness which was compared to the theoretical predictions using the Halpin Tsai model and its modified versions.
Usuki, A., Kojima, Y., Kawasumi, M., Okada, A., Fukushima, Y., Kurauchi, T. and Kamigaito, O. (1993). Synthesis of Nylon 6-Clay Hybrid, Journal of Materials Research, 8(5): 1179—1184.
Gilman, J.W. , Jackson, C.L., Morgan, A.B., Harris, R., Manias, E., Giannelis, E.P., Wuthenow, M., Hilton, D. and Phillips, S.H. (2000). Flammability Properties of Polymer-Layered Silicate Nanocomposites. Polypropylene and Polystyrene Nanocomposites, Chemistry of Materials,12(7): 1866—1873.
4.
LeBaron, P.C. , Wang, Z. and Pinavaia, T.J. (1999). Polymer-Layered Silicate Nanocomposites: An Overview, AppliedClay Science, 15(1—2): 11—29.
5.
Alexandre, M. and Dubois, P. (2000). Polymer-Layered Silicate Nanocomposites: Preparation, Properties and Uses of a New Class of Materials , Materials Science and Engineering R, 28(1—2): 1—63.
6.
Osman, M.A., Mittal, V., Morbidelli, M. and Suter, U.W. (2003). Polyurethane Adhesive Nanocomposites as Gas Permeation Barrier, Macromolecules,36(26): 9851—9858.
7.
Pukanszky, B. (1995). In: Karger-Kocsis, J. (ed.), Polypropylene Structure, Blends and Composites. Volume 3, Chapman and Hall, London.
8.
Sun, T. and Garces, J.M. (2002). High Performance Polypropylene-Clay Nanocomposites by In-Situ Polymerization With Metallocene/Clay Catalysts, Advanced Materials, 14(2): 128—130.
9.
Kawasumi, M., Hasegawa, N., Kato, M., Usuki, A. and Okada, A. (1997). Preparation and Mechanical Properties of Polypropylene-Clay Hybrids, Macromolecules,30(20): 6333—6338.
10.
Oya, A., Kurokawa, Y. and Yasuda, H. (2000). Factors Controlling Mechanical Properties of Clay Mineral/Polypropylene Nanocomposites, Journal of MaterialsScience, 35(5): 1045—1050.
11.
Xu, W., Liang, G., Wang, W., Tang, S., He, P. and Pan, W.P. (2003). PP-PP-g-MAH-Org-MMT Nanocomposites. I. Intercalation Behavior and Microstructure, Journal of AppliedPolymer Science , 88(14): 3225—3231.
12.
Ellis, T.S. and D'Angelo, J.S. (2003). Thermal and Mechanical Properties of a Polypropylene Nanocomposite, Journal of AppliedPolymer Science, 90(6): 1639—1647.
13.
Su, S., Jiang, D.D. and Wilkie, C.A. (2004). Poly(methyl methacrylate), Polypropylene and Polyethylene Nanocomposite Formation by Melt Blending Using Novel Polymerically-Modified Clays, Polymer Degradation and Stability, 83(2): 321—331.
14.
Reichert, P. , Nitz, H., Klinke, S., Brandsch, R., Thomann, R. and Mülhaupt, R. (2000). Poly(propylene)/Organoclay Nanocomposite Formation: Influence of Compatibilizer Functionality and Organoclay Modification, Macromolecular Materials and Engineering, 275(1): 8—17.
15.
Lertwimolnun, W. and Vergnes, B. (2005). Influence of Compatibilizer and Processing Conditions on the Dispersion of Nanoclay in a Polypropylene Matrix, Polymer, 46(10): 3462—3471.
16.
Hasegawa, N. , Kawasumi, M., Kato, M., Usuki, A. and Okada, A. (1998). Preparation and Mechanical Properties of Polypropylene-Clay Hybrids Using a Maleic Anhydride-Modified Polypropylene Oligomer, Journal of AppliedPolymer Science , 67(1): 87—92.
17.
Wang, Y., Chen, F.-B., Li, Y.-C. and Wu, K.-C. (2004). Melt Processing of Polypropylene/ Clay Nanocomposites Modified with Maleated Polypropylene Compatibilizers, Composites Part B: Engineering,35(2):111—124.
18.
Kato, M., Usuki, A. and Okada, A. (1997). Synthesis of Polypropylene Oligomer-Clay Intercalation Compounds, Journal of AppliedPolymer Science, 66(9): 1781—1785.
19.
Hasegawa, N. , Okamoto, H., Kawasumi, M., Kato, M., Tsukigase, A. and Usuki, A. (2000). Polyolefin-Clay Hybrids Based on Modified Polyolefins and Organophilic Clay, Macromolecular Materials and Engineering,280/281(1): 76—79.
20.
Osman, M.A. , Rupp, J.E.P. and Suter, U.W. (2005). Gas Permeation Properties of Polyethylene-Layered Silicate Nanocomposites, Journal of Materials Chemistry, 15(12): 1298—1304.
21.
Osman, M.A. , Mittal, V. and Suter, U.W. (2007). Poly(propylene)-Layered Silicate Nanocomposites: Gas Permeation Properties and Clay Exfoliation, Macromolecular Chemistry andPhysics, 208(1): 68—75.
22.
Osman, M.A. and Rupp, J.E.P. (2005). Interfacial Interactions and Properties of Polyethylene-Layered Silicate Nanocomposites, MacromolecularRapid Communications, 26(11): 880—884.
23.
Osman, M.A. , Atallah, A. and Suter, U.W. (2004). Influence of Excessive Filler Coating on the Tensile Properties of LDPE-Calcium Carbonate Composites , Polymer, 45(4): 1177—1183.
24.
Osman, M.A., Ploetze, M. and Suter, U.W. (2003). Surface Treatment of Clay Minerals- Thermal Stability, Basal-Plane Spacing and Surface Coverage, Journal of Materials Chemistry, 13(9): 2359—2366.
25.
Morgan, A.B. and Harris, J.D. (2003). Effects of Organoclay Soxhlet Extraction on Mechanical Properties, Flammability Properties and Organoclay Dispersion of Polypropylene Nanocomposites, Polymer, 44(8): 2313—2320.
26.
Fornes, T.D., Yoon, P.J. and Paul, D.R. (2003). Polymer Matrix Degradation and Color Formation in Melt Processed Nylon 6/Clay Nanocomposites, Polymer, 44(24): 7545—7556.
27.
Wee, J.W., Lim, Y.T. and Park, O.O. (2000). Thermal Characteristics of Organoclay and their Effects upon the Formation of Polypropylene/Organoclay Nanocomposites, PolymerBulletin, 45(2): 191—198.
28.
Kerner, E.H. (1956). The Elastic and Thermo-Elastic Properties of Composite Media, Proceedings of the Physical Society, B69(8): 808—813.
29.
Hashin, Z. and Shtrikman, S. (1963). A Variational Approach to the Theory of the Elastic Behavior of Multiphase Materials, Journal of the Mechanics andPhysics of Solids, 11(2): 127—140.
30.
Halpin, J.C. (1969). Stiffness and Expansion Estimates for Oriented Short Fiber Composites, Journal ofComposite Materials, 3(4): 732—734.
31.
Halpin, J.C. (1992). Primer on Composite Materials Analysis, Technomic, Lancaster.
32.
van Es, M., Xiqiao, F., van Turnhout, J. and van der Giessen, E. (2001). In: Al-Malaika, S., Golovoy, A.W. and Wilkie, C.A. (eds) Specialty Polymer Additives: Principles and Application, Blackwell Science, CA Melden, MA.
33.
Fornes, T.D. and Paul, D.R. (2003). Modeling Properties of Nylon 6/Clay Nanocomposites Using Composite Theories, Polymer, 44(17): 4993—5013.
34.
Brune, D.A. and Bicerano, J. (2002). Micromechanics of Nanocomposites: Comparison of Tensile and Compressive Elastic Moduli, and Prediction of Effects of Incomplete Exfoliation and Imperfect Alignment on Modulus, Polymer, 43(2): 369—387.
35.
Osman, M.A. and Suter, U.W. (2000). Determination of Cation-Exchange Capacity of Muscovite Mica, Journal of Colloid and InterfaceScience, 224(1): 112—115.
36.
Osman, M.A. , Ploetze, M. and Skrabal, P. (2004). Structure and Properties of Alkylammonium Monolayers Self-Assembled on Montmorillonite Platelets, Journal ofPhysical Chemistry B, 108(8): 2580—2588.
37.
Edgecombe, S.R., Gardiner, J.M. and Matsen, M.W. (2002). Suppressing Autophobic Dewetting by using a Bimodal Brush, Macromolecules,35(16): 6475—6477.
38.
Dennis, H.R. , Hunter, D.L., Chang, D., Kim, S., White, J.L., Cho, J.W. and Paul, D.R. (2001). Effect of Melt Processing Conditions on the Extent of Exfoliation in Organoclay-Based Nanocomposites , Polymer, 42(23): 9513—9522.
39.
Rybnikar, F. (1991). Interactions in the System Isotactic Polypropylene-Calcite, Journal of AppliedPolymer Science, 42(10): 2727—2737.
40.
Supaphol, P. , Harnsiri, W. and Junkasem, J. (2004). Effects of Calcium Carbonate and its Purity on Crystallization and Melting Behavior, Mechanical Properties, and Processability of Syndiotactic Polypropylene, Journal of AppliedPolymer Science, 92(1): 201—212.
41.
Svoboda, P. , Zeng, C., Wang, H., Lee, L.J. and Tomasko, D.L. (2002). Morphology and Mechanical Properties of Polypropylene/Organoclay Nanocomposites, Journal of AppliedPolymer Science, 85(7): 1562—1570.
42.
Maiti, P., Nam, P.H., Okamoto, M., Hasegawa, N. and Usuki, A. (2002). Influence of Crystallization on Intercalation, Morphology, and Mechanical Properties of Polypropylene/Clay Nanocomposites , Macromolecules,35(6): 2042—2049.
43.
Osman, M.A. , Rupp, J.E.P. and Suter, U.W. (2005). Tensile Properties of Polyethalene-Layered Silicate Nanocomposites, Polymer, 46(5): 1653—1660.
44.
Luo, J.J. and Daniel, I.M. (2003). Characterization and Modeling of Mechanical Behavior of Polymer/Clay Nanocomposites, CompositesScience and Technology , 63(11): 1607—1616.
45.
Wu, Y.P., Jia, Q.X., Yu, D.S. and Zhang, L.Q. (2004). Modeling Young's Modulus of Rubber-Clay Nanocomposites Using Composite Theories, Polymer Testing,23(8): 903—909.
46.
Nicolais, L. and Nicodemo. L. (1973). Strength of Particulate Composite, Polymer Engineering and Science, 13(6): 469—469.
47.
Nielsen, L.E. (1966). Simple Theory of Stress-Strain Properties of Filled Polymers, Journal of AppliedPolymer Science, 10(1): 97—103.
