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as a filler in PU matrices. As a result of the inclusion of functional nanofillers in the
PU matrix, a high-performance shape recovery of more than 95% was obtained in
the nanodiamond-loaded composites (0.5–2%), due to the better interactions
between the functional nanodiamonds and the PU, thus leading to better mechanical
properties and shape recovery. Thus, the development and integration of functional
nanodiamonds in the PU matrix can result in increased mechanical strength and
shape memory properties.
4.5 Application of Shape Memory PUs and Their
Nanocomposites
Conductive nanofiller-loaded shape memory PUs have shown good electrical,
mechanical, shape recovery, and thermal properties (Zhao et al. 2015). Fibrous
material-reinforced shape memory PUs have been used in the aerospace industry in
deployable solar panels, extendible tubular booms, hinges, morphing wings, reflective antennas, roll-up booms and truss booms (Lan et al. 2009; Liu et al. 2014). PU
and their nanocomposites also have a thermo-sensitive shape recovery effect.
However, external heating can sometimes be derogatory to stimulate the conventional shape memory effect. These materials have also been used to avoid the shock
effect and heavy weight. The electroactivate shape memory PUs and their nanocomposites have been used in actuators, and their actuation performance has been used
for space vehicles (Hager et al. 2015). Conductive nanofiller-loaded shape memory
PUs can cause spontaneous electric triggering of the PU nanocomposites due to
technological relevance. The shape recovery rate generally depends on the magnitude of the applied voltage in electrically-induced shape memory materials. The
carbon black NP-loaded PU nanocomposites have shown an improved electroactive
memory effect compared to the micro-sized conductive filler-loaded PU nanocomposites (Włoch et al. 2019). Furthermore, the nanofiller can form a conductive network interconnected with homogeneously dispersed NPs. The high nanofiller load
can also cause aggregation and low conductivity properties. In addition, the poor
dispersion of nanofiller in the matrix can lead to low σ m and E values in shape
memory PUs.
Shape memory PUs have also found application for biomedical devices and systems (Leng et al. 2011). For example, Neffe et al. (2009) studied the biodegradability and the effect of drug release in a shape memory PU. In this context, controlled
drug release can be designed from appropriate switching segments and network
structures, which can be activated by mechanical or thermal stimuli to allow drug
diffusion (Small IV et al. 2005). Shape memory PUs have also been suggested for
removal of the blood clots (Small IV et al. 2005). This is possible due to the shape
recovery effect of the PU microactuator (Fig. 4.5). These materials can also be used
for dental applications such as orthodontia (Jung and Cho 2010).
A. Kausar
as a filler in PU matrices. As a result of the inclusion of functional nanofillers in the
PU matrix, a high-performance shape recovery of more than 95% was obtained in
the nanodiamond-loaded composites (0.5–2%), due to the better interactions
between the functional nanodiamonds and the PU, thus leading to better mechanical
properties and shape recovery. Thus, the development and integration of functional
nanodiamonds in the PU matrix can result in increased mechanical strength and
shape memory properties.
4.5 Application of Shape Memory PUs and Their
Nanocomposites
Conductive nanofiller-loaded shape memory PUs have shown good electrical,
mechanical, shape recovery, and thermal properties (Zhao et al. 2015). Fibrous
material-reinforced shape memory PUs have been used in the aerospace industry in
deployable solar panels, extendible tubular booms, hinges, morphing wings, reflective antennas, roll-up booms and truss booms (Lan et al. 2009; Liu et al. 2014). PU
and their nanocomposites also have a thermo-sensitive shape recovery effect.
However, external heating can sometimes be derogatory to stimulate the conventional shape memory effect. These materials have also been used to avoid the shock
effect and heavy weight. The electroactivate shape memory PUs and their nanocomposites have been used in actuators, and their actuation performance has been used
for space vehicles (Hager et al. 2015). Conductive nanofiller-loaded shape memory
PUs can cause spontaneous electric triggering of the PU nanocomposites due to
technological relevance. The shape recovery rate generally depends on the magnitude of the applied voltage in electrically-induced shape memory materials. The
carbon black NP-loaded PU nanocomposites have shown an improved electroactive
memory effect compared to the micro-sized conductive filler-loaded PU nanocomposites (Włoch et al. 2019). Furthermore, the nanofiller can form a conductive network interconnected with homogeneously dispersed NPs. The high nanofiller load
can also cause aggregation and low conductivity properties. In addition, the poor
dispersion of nanofiller in the matrix can lead to low σ m and E values in shape
memory PUs.
Shape memory PUs have also found application for biomedical devices and systems (Leng et al. 2011). For example, Neffe et al. (2009) studied the biodegradability and the effect of drug release in a shape memory PU. In this context, controlled
drug release can be designed from appropriate switching segments and network
structures, which can be activated by mechanical or thermal stimuli to allow drug
diffusion (Small IV et al. 2005). Shape memory PUs have also been suggested for
removal of the blood clots (Small IV et al. 2005). This is possible due to the shape
recovery effect of the PU microactuator (Fig. 4.5). These materials can also be used
for dental applications such as orthodontia (Jung and Cho 2010).
A. Kausar