Shape memory composites

By hybridization or incorporation of inorganic materials in SMP, smart composites can be produced, combining the unique function or property of each component [51]. The morphology and mechanical properties of such composites have been reported recently [52]. The addition of conducting carbon black (CB) 

Thermal properties of phenoxy/TPU blends [45] glass transition tempera- 

The shape memory effect in polymers is based on a large difference in the glassy 

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Madbouly SA, Lendlein A (2009) Shape-Memory Composites. In Advances in Polymer Sciences, Volume Shape-Memory Polymers, Springer... 

Cuevas J et al (2012) Shape memory composites based on glass-fibre-reinforced poly(ethylene)-like polymers. Smart Mater Struct 21(3) 035004... 

Mosleh Y et al (2014) TPU/PCL/nanomagnetite ternary shape memory composites studies on their thermal, dynamic-mechanical, rheological and electrical properties. Iranian Polym J 23(2) 137-145... 

Boyd, J.G. Lagoudas, D.C. Thermomechanical response of shape memory composites. J. Intelligent Material Systems and Structures, 5 (1994), pp. 333 346... 

Cuevas, J. M., Alonso, J., German, L., Iturrondobeitia, M, Laza, J. M., et al. (2009), Magneto-active shape memory composites by incorporating ferromagnetic microparticles in a thermo-responsive polyalkenamer. Smart Materials and Structures, 18,075003. 

The design of smart materials and adaptive stmctures has required the development of constitutive equations that describe the temperature, stress, strain, and percentage of martensite volume transformation of a shape-memory alloy. These equations can be integrated with similar constitutive equations for composite materials to make possible the quantitative design of stmctures having embedded sensors and actuators for vibration control. The constitutive equations for one-dimensional systems as well as a three-dimensional representation have been developed (7). 

Finally, metallic fibers find some limited applications as reinforcement in composites. They are generally not desirable due to their inherently high densities and because they present difficulties in coupling to the matrix. Nonetheless, tungsten fibers are used in metal-matrix composites, as are steel fibers in cement composites. There is increasing interest in shape memory alloy filaments, such as Ti-Ni (Nitanol) for use in piezoelectric composites. We will discuss shape-memory alloys and nonstructural composites in later chapters of the text. 

Other shape memory alloys are listed in Table 20.1, and Figure 20.3 shows the dependence of the Ms temperature for Cu-Zn-Al alloys on composition. For the copper-base alloys controlled cooling is necessary after heating into the (3 phase region. 

The dependence of the Ms temperature of copper-zinc-aluminum alloys on composition. The dots indicate alloys for which the Ms has been measured. Data from D. E. Hodgson, M. H. Wu, and R. J. Biermann, Shape Memory Alloys, Johnson Matthey, http //www.jmmedical.com/html/. shape.memory.alloysJitml (accessed May 6, 2006). 

The temperature for the acoustic damping capacity change from Nitinol was found to be different for alloys that were prepared at different laboratories (even though both alloys have identical composition). Further, the shape memory response to temperature change, such as how fast and how much force, also varied a great deal from one alloy to another. 

The above analysis takes the synthesis methods, the performance affected by the dispersion of CNTs, enhanced physical properties and the latest applications of carbon nanotube/polyurethane composites described in literature reports as the reference point. In the interest of brevity, this is not a comprehensive review, however, it goes through numerous research reports and applications which have been learned and described in the recent years. Despite that, there are still many opportunities to synthesize new carbon nano-tube/polyurethane systems and to modify carbon nanotubes with new functional groups. The possibility of producing modern biomedical and shape memory materials in that way makes the challenge of the near future. 

As seen in the previous sections, carbon nanotubes can improve mechanical properties and bring electrical conductivity to PVA materials. Moreover, other original properties of PVA/nanotube composites have been reported over the last years. Among them, we can cite the remarkable capability of some nanotube/PVA composites to absorb mechanical energy and shape memory phenomena that differ from traditional behaviors of other polymers. 

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