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Polyurethane shape memory polymers (PU-SMPs) are active materials that can be transformed into complex shapes with
the ability to recover their original shape even after undergoing large deformations. Because of their light weight,
large recoverability, low cost, and high compliance, SMPs can be potentially employed as actuators, MEMS devices,
temperature sensors, and damping elements to name a few. One of the key challenges in implementing SMPs is
the response time which is limited by the method of heating and cooling and the material. Unlike shape memory alloys,
SMPs can be activated by multiple stimuli including lasers, resistive heating, electric fields, and magnetic fields.
While these methods may provide an efficient way of heating the SMP, they rely on the slow process of passive
conduction for cooling. In this paper, a self regulating SMP (SR-SMP) composite is introduced, whereby a novel
heating and cooling system consisting of embedded silica capillary tubes in the SMP (DiAPLEX® MP4510: SMP
Technologies, Inc.) has been developed. The tubes are used to pump hot/cold fluid through the SMP membrane and
hence provide a local temperature source. In order to show the effectiveness and efficiency of the mechanism, the
thermomechanical response of the SR-SMP is compared experimentally to a SMP with "conventional" i.e. global
heating and cooling mechanisms. It is shown that the SR-SMP has a faster thermomechanical response. It has been
demonstrated previously that soft SMPs can be controlled by an electric field while in the rubbery phase, thus taking
advantage of the Maxwell stress or electrostatic stress effect. Thermomechanical characterization of PU-SMPs is
described for different weight percentages of resin (Diphenylmethane-4, 4'-diisocyanate) and hardener (1,4-Butanediol).
Varying the percent hardener reduced the effective cross-link density of the polymer and hence the thermomechanical
properties. The electromechanical response of pure SMP and SR-SMP is predicted numerically. The numerical
computation indicates that the softer SMPs (resin:hardener = 5:4, 8:7, and 9:8) could be used as electroactive polymers.
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