Shape memory polyurethanes materials

Another promising field which we will follow will be to do research in the area of biomedicine where candidate shape memory polyurethane materials could enable... 

Goo et al. investigated the actuation durability of a conducting shape memory polyurethane/MWNT (CSMPU) actuator and concluded that the number of cycles at breaking decreased, as the actuation temperature increased (108). The possible reason is that more material degradation of CSMPU can be induced due to rapid and large movement of polymer chains as the actuation temperature increases. For a CSMPU actuator, the authors confirmed that an actuation temperature that is higher than the transition temperature produces a rapid response but low durability. 

As compared to metallic compounds used as shape memory materials, shape memory polymers have low density, high shape recoverability, easy processability, and low cost. Since the discovery by Mitsubishi in 1988, polyurethane SMPs have attracted a great deal of attention due to their unique properties, such as a wide range of shape recovery temperatures (— 30°C to 70°C) and excellent biocompatibility, besides the usual advantages of plastics. A series of shape memory polyurethanes (SPMUs), prepared from polycaprolactone diols (PCL), 1,4-butanediol (BDO) (chain extender), and 4,4 -diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI) have recently been introduced [200—202]. 

A relatively new and exciting application for polymers is as shape memory materials. Therefore, one of the objectives which we will continue to follow in the immediate future will be to focus on novel crosslinked shape-memory polyurethanes. 

Orthodontics is an area in which polymers are desirable for both their esthetic appeal and shape-memory effect. In 2007, Eliades published an opinion paper on projected future materials for orthodontics and discussed research into polymer-based archwires [67]. In the following year, Jung and Cho demonstrated the use of shape-memory polyurethanes for arch wires [68]. An in vitro dental model was used to test the correction of misaligned teeth and can be seen in Fig. 10. The melt spun polymer, synthesized from 4,4 -methylene bis(phenylisocyanate) and PCL-diol, was stretched to the length required to realign the teeth and attached to stainless... 

Rodriguez, J.N., Clubb, F.J., Wilson, T.S., Miller, M.W., Fossum, T.W., Hartman, J., Tuzun, E., Singhal, R, Maitland, D.J., 2014. In vivo response to an implanted shape memory polyurethane foam in a porcine aneurysm model. Journal of Biomedical Materials Research Part... 

Jung, Y, Cho, J. (2010). Application of shape memory polyurethane in orthodontic (Translated from English). Journal of Materials Science Materials in Medicine, 27(10), 2881-2886 (in English). 

The change in electric conductivity by varying the applied stress, the filler type and concentration and the temperature of materials has been extensively reported (Gunes et al, 2009 Leng et al, 2007). Cho (2005) investigated shape memory polyurethanes with multiwall CNTs. The author evidenced two important results the enhancement of mechanical properties of the nanocomposite with respect to the neat matrix and its electrosensitive response, making it a good candidate for an electrical actuator. 

Zhu Y, H.J., Yeung L.Y., Liu Y, Ji F.L. and Yeung K.W. (2006), Development of shape memory polyurethane fiber with complete shape recoverability. Smart Materials and Structures, 15 pp. 1385-1394. 

Zhuo H.T., Hu J.L. and Chen S.J. (2008), Electrospun polyurethane nanofibres having shape memory effect. Materials Letters, 62(14) pp. 2074-2076. 

Zhuo H., Hu J. and Chen S. (2011), Study of the thermal properties of shape memory polyurethane nanofibrous Journal of Materials Science, 46 ... 

Huang H., Zhang D., Wang T.J., Mao Z.P., Yu W.D. and Yan H.J. (2007), Influence of hard segment content on the water vapor permeabUity of segmented shape memory polyurethane membranes. Proceedings of the 2007 International Conference on Advanced Fibers and Polymer Materials, 1-2 ... 

Razzaq, M. Y, Anhalt, M., Froimann, L., Weidenfeller, B. (2007a), Mechanical spectroscopy of magnetite fiUed polyurethane shape memory polymers. Materials Science and Engineering A, 471, 57-62. 

Zhu, Y, Hu, J., Yeung, L.-Y, Lu, J., Meng, Q., etal. (2007a), Effect of steaming on shape memory polyurethane fibers with various hard segment contents. Smart Materials and Structures, 16, 969-81. 

Tobushi, H., Hara, H., Yamada, E., Hayashi, S. (1996), Thermo-mechaiucal properties in a thin film of shape memory polymer of polyurethane series. Smart Mater. Struct., 5,483. Zhu, Y, Hu, J. L., Yeung, L. Y, Liu, Y, Ji, F. L., Yeung, K. W. (2006), Development of shape memory polyurethane fiber with complete shape recoverability. Smart Materials and Structures, 15, p. 1385-94. 

Sahoo, N. G., Jung, Y. C., Goo, N. S., Cho, J. W. (2005), Conducting shape memory polyurethane-polypyirole composites for an electroactive actuator, Macromolecular Materials and Engineering, 290,1049-55. 

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