Polymer composite strength

P. M. Ajayan, L. S. Schadler, C. Giannaris, A. Rubio, Single-Walled Carbon Nanotube-Polymer Composites Strength and Weakness. Adv Mater 2000, 12,750-753. 

Ajayan, P. M., Schadler, L. S., Giannaris, C., and Rubio, A. Single-walled carbon nano-tube-polymer composites strength and weakness. Adv Mater., 12,750-3 (2000). 

Ajayan P M, Schadler L S, Giannaris S C, Rubio A, Single-walled carbon nanotube-polymer composites strength and weakness . Advanced Materials, 2000 12 (10) 750-753. 

The importance of polymer composites arises largely from the fact that such low density materials can have unusually high elastic modulus and tensile strength. Polymers have extensive applications in various fields of industry and agriculture. They are used as constructional materials or protective coatings. Exploitation of polymers is of special importance for products that may be exposed to the radiation or temperature, since the use of polymers make it possible to decrease the consumption of expensive (and, sometimes, deficient) metals and alloys, and to extent the lifetime of the whole product. 

Density and polymer composition have a large effect on compressive strength and modulus (Fig. 3). The dependence of compressive properties on cell size has been discussed (22). The cell shape or geometry has also been shown important in determining the compressive properties (22,59,60,153,154). In fact, the foam cell stmcture is controlled in some cases to optimize certain physical properties of rigid cellular polymers. 

Those stmctural variables most important to the tensile properties are polymer composition, density, and cell shape. Variation with use temperature has also been characterized (157). Flexural strength and modulus of rigid foams both increase with increasing density in the same manner as the compressive and tensile properties. More specific data on particular foams are available from manufacturers Hterature and in References 22,59,60,131 and 156. Shear strength and modulus of rigid foams depend on the polymer composition and state, density, and cell shape. The shear properties increase with increasing density and with decreasing temperature (157). 

These composites and the information gained from stndying them have set the stage for the next generation of polymer composites, based on high-strength fibers such as the aramids. 

Fu, S. and Lauke, B Effects of fiber length and fiber orientation distributions on the tensile strength of short-fiber-reinforced polymers, Composites Sci. Technol., 56, 1179 (1996). 

Wetherhold, R. C., Statistical distribution of strength of fiber-reinforced composite materials, Polym. Composites, 7, 116 (1986). 

Brink, A. E., Owens, J. T., Oshinski, A. J. and Pecorini, T. J., Process for preparing high strength fiber reinforced polymer composites, US Patent 6 048 922, 2000. 

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