Carbon nanotube -polymers shape-memory

Keywords Carbon nanotubes Nanoparticle Shape-memory effect Shape-memory polymer composite Stimuli-sensitive polymer... 

Zhang CS, Ni QQ, Fu SY, Kurashiki K (2007) Electromagnetic interference shielding effect of nanocomposites with carbon nanotube and shape memory polymer. Compos Sci Technol 67(14) 2973-2980. doi 10.1016/j.compscitech.2007.05.011... 

Al-Saleh MH, Sundararaj U (2009) Electromagnetic interference shielding mechanisms of CNT/polymer composites. Carbon 47(7) 1738-1746. doi 10.1016/j.carbon.2009.02.030 Jin X, Ni QQ, Natsuki T (2011) Composites of multi-walled carbon nanotubes and shape memory polyurethane for electromagnetic interference shielding. J Compos Mater 45(11) 2547-2554. doi 10.1177/0021998311401106... 

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. 

TABLE 16.2 Comparison between Two Mechanical Properties of Different Actuating Materials Skeletal Muscles, Thermomechanical (Thermal Liquid Crystals and Thermal Shape Memory Alloys), Electrochemomechanical (Conducting Polymers and Carbon Nanotubes) and Electromechanical (Ionic Polymer Metal Composites, Field Driven Liquid Crystal Elastomers, Dielectric Elastomers)... 

Recently, the concept of cold hibernated elastic memory utilising SMP in open cellular structures was proposed for space-bound structural applications [108]. The concept of cold-hibernated elastic memory can be extended to various new applications such as microfoldable vehicles, shape determination and microtags [109]. Recent studies on shape memory PU-based conductive composites using conducting polymers and carbon nanotubes show considerable promise for application as electroactive and remote sensing actuators [110]. 

A reduction of the required energy could be reached by the incorporation of conductive fillers such as heat conductive ceramics, carbon black and carbon nanotubes [103-105] as these materials allowed a better heat distribution between the heat source and the shape-memory devices. At the same time the incorporation of particles influenced the mechanical properties increased stiffness and recoverable strain levels could be reached by the incorporation of microscale particles [106, 107], while the usage of nanoscale particles enhanced stiffness and recoverable strain levels even more [108, 109]. When nanoscale particles are used to improve the photothermal effect and to enhance the mechanical properties, the molecular structure of the particles has to be considered. An inconsistent behavior in mechanical properties was observed by the reinforcement of polyesterurethanes with carbon nanotubes or carbon black or silicon carbide of similar size [3, 110]. While carbon black reinforced materials showed limited Ri around 25-30%, in carbon-nanotube reinforced polymers shape-recovery stresses increased and R s of almost 100% could be determined [110]. A synergism between the anisotropic carbon nanotubes and the crystallizing polyurethane switching segments was proposed as a possible... 

To ground the readers and provide benchmarks for comparisons of the SMPlNCs, Section 2 presents a brief outline of recent advances in shape memory polymer-organic composites, with a focus on carbon nanomaterials such as graphene, carbon nanotubes, and carbon black. 

Li H et al (2013) The reinforcement efficiency of carbon nanotubes/shape memory polymer nanocomposites. Compos B Eng 44(1) 508-516... 

Breuer, O. and Sundararaj, U. (2004), Big returns from small fibres A review of polymer/ carbon nanotube composites . Polymer Composites, Vol. 25, Issue 6, pp. 630-645. Br0ndsted, P., Lystrup, A. and Lilholt, H. (2005), Composite materials for wind power turbine blades . Annual Review of Materials Research, Vol. 35, pp. 505-538. Buckley, P.R., McKinley, G.H., Wilson, T.S., Small, W., Benett, W.J., Bearinger, J.P., McElfresh, M.W. and Maitland, D.J. (2006), Inductively heated shape memory polymer for the magnetic actuation of medical devices , IEEE Trans Biomed Eng, Vol. 53, Issue 10, pp. 2075-2083. 

Sahoo, N. G., Jung, Y. C., Cho, J. W. (2007a), Electroactive shape memory effect of polyurethane composites filled with carbon nanotubes and conducting polymer. Mater. Manuf. Process., 22,419-23. 

Yu K, Zhang Z, Liu Y, Leng J (2011) Carbon nanotube chains in a shape memory polymer/caibon black composite to significanfly reduce the electrical resistivity. Appl Phys Lett 98 074102... 

Nanocomposites offer opportunities to enhance the performance of active polymers. Opportunities arise from the extensive polymer-nanoparticle interface the responsiveness of the percolative nanoparticle network and the impact of nanoparticles on the local electric field. For example, carbon nanotube addition to shape memory polyurethane increases blocking stress and provides electrical and optical triggering of recovery. Similarly, carbon nanotubes modify the local electric field in the surrounding polymer, decreasing the actuation voltage for ferroelectric polymers. Challenges facing characterization and the establishment of structure-property correlations will be discussed. 

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