Researchers at the University of South Florida have developed a technology that combines two components, single and multi-walled carbon nanotubes and a specific type of themoplastic polyurethane polymer.
The carbon nanotubes are dispersed throughout the polymer matrix. The material created from combining these two substances has been shown to have increased break strength, yet still possesses an ultra-soft configuration. Another very interesting and beneficial result of dispersing the carbon nanotubes within the polymeric matrix is the resulting self-healing characteristics of the newly formed material.
More specifically, upon breaking, tearing, or cutting formed samples of the polyurethane containing carbon nanotubes, the fragmented surfaces can be rejoined and form a cohesive complex that retains some of the initial mechanical properties. The longer the material is allowed to remain together after rejoining and before restressing, the closer the material gets to the initial state and levels off at approximately two thirds of the initial break strength. This "healing" process is highly increased by warming the material to just under the glass transition temperature of the material's hard segments (65-70 degrees Celsius).
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