Abstract
The objectives of this work were (a) to investigate the influence of micrometer and submicrometer scale graphite platelets of different aspect ratios and volume fractions on the effective and local quasi-static and dynamic properties of composites with micrometer and submicrometer scale reinforcement, and (b) to compare and evaluate mechanical property measurements of inhomogeneous materials via local (microscale) and bulk (macroscale) experimental methods. Small platelet volume fractions (0.5%) provided proportionally larger increase of the elastic and storage moduli compared to large volume fractions (3.0%). Randomly distributed 15 μm platelets provided marginally higher composite stiffness compared to 1 μm platelets while small volume fractions (0.5%) of 15 μm platelets had a pronounced effect on the effective Poisson's ratio. It was found that local property measurements of inhomogeneous materials conducted by nanoindentation are not representative of the bulk behavior even when the characteristic length of the inhomogeneity is an order of magnitude smaller than the indentation contact area. In this case, statistical averaging of data from a large number of indentations does not result in agreement with bulk measurements. On the other hand, for small aspect ratio platelets with dimensions two orders of magnitude smaller than the nanoindentation contact area, the nanoindenter-obtained properties agreed well with the effective material behavior. It was found that platelets residing at the specimen surface contribute the most to nanoindentation data, which implies that this technique is only valid for well-distributed nanoparticulate and microparticulate systems, and that nanoindentation cannot be used for depth profiling of microstructured composites.
Similar content being viewed by others
References
Pinnavaia, T.J. and Beal, G.W., editors, Polymer-Clay Nannocomposites, Wiley, New York (2001).
Nanocomposites 1999: Polymer Technology for the Next Century, Principia Partners, Exton, PA (1999).
Vaia, R.R. andGiannelis, E.P., “Polymer Nanocomposites: Status and Opportunities,” MRS Bulletin26,(5), 394–401 (2001).
Fukuskima, H. and Drzal, L. T., “Graphite Nanoplatelets as Reinforcements for Polymers: Structural and Electrical Properties,” Proceedings of the 16th Annual American Society of Composites Consites Conference, Blacksburg, VA, September 10–12 (2001).
Chasiotis, L., Chen, Q., and Odegard, G., “Multiscale Experiments of Polymer Nanocomposites,” Proceedings of the Society for Experimental Mechanics, Costa Mesa, CA (2004).
Testworks 4 Software Manual for Nanoindentation Systems. Version 14, MTS System Corporation, Oak Ridge (2001).
Penumadu, D., Dutta, A., Pharr, G.M., andFiles, B., “Mechanical Properties of Blended Single-wall Carbon Nanotube Composites,”Journal of Materials Research,18,(8), 1849–1853 (2003).
Li, X. andBhushan, B.: “A Review of Nanoindentation Continuous Stiffness Measurement Technique and its Applications,” Materials Characterization,48,11–36 (2002).
Shen, L., Phang, I.Y., Chen, L., Liu, T., and Zeng, K., “Nanoindentation and Morphological Studies on Nylon 66 Nanocomposites. I: Effect of Clay Loading,” Polymer,45,3341–3349 (2004).
Oliver, W.C. and Pharr, G.M., “An Improved Technique for Determining Hardness and Elastic Modulus Using Load and Displacement Sensing Indentation Experiments,” Journal of Materials Research,7 (6), 1564–1583 (1992).
Odegard, G.M., Gates, T.S. and Herring, H.M., “Characterization of Viscoelastic Properties of Polymeric Materials Through Nanoindentation,” Experimental Mechanics,45, (2), 130–136 (2005).
Cano, R.J. and Dow, M.B., “Properties of Five Toughened Composite Materials,” NASA TP-3254, NASA LaRC (1992).
VanLandingham, M.R., Villarrubia, J.S., Guthrie, W.F., and Meyers, G.F., “Nanoindentation of Polymers: An Overview,” Macromolecular Symposia,167,15–43 (2001).
Cheng, L., Xia, X., Yu, W., Scriven, L.E., and Gerberich, W.W., “Flatpunch Indentation of Viscoelastic Material,” Journal of Polymer Science Part B: Polymer Physics,38, (1), 10–22 (2000).
Lu, H., Wang, B., Ma, J., Huang, G., and Viswanathan, H., “Measurement of Creep Compliance of Solid Polymers by Nanoindentation,” Mechanics of Time-Dependent Materials,7 (3–4), 189–207 (2003).
Liu, C., “On the Minimum Size of Representative Volume Element,” Proceedings of the Society for Experimental Mechanics, X International Congress, Costa Mesa, CA, June 7–10 (2004).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Chasiotis, I., Chen, Q., Odegard, G.M. et al. Structure-property relationships in polymer composites with micrometer and submicrometer graphite platelets. Experimental Mechanics 45, 507–516 (2005). https://doi.org/10.1007/BF02427904
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02427904