Recent advances in shape–memory polymers: Structure, mechanism, functionality, modeling and applications

Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding

Stimulus-responsive shape memory materials: A review

The past several years have witnessed significant advances in the field of shape memory polymers (SMPs) with the elucidation of new compositions for property tuning, the discovery of new mechanisms for shape fixing and recovery, and the initiation of phenomenological modeling. We critically review research findings on new shape memory polymers along these lines, emphasizing exciting progress in the areas of composites, novel recovery triggering, and new application developments.

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Shape Memory Polymer Research

As a new class of smart materials, shape memory polymers and their composites (SMPs and SMPCs) can respond to specific external stimulus and remember the original shape. There are many types of stimulus methods to actuate the deformation of SMPs and SMPCs, of which the thermal- and electro-responsive components and structures are common. In this review, the general mechanism of SMPs and SMPCs are first introduced, the stimulus methods are then discussed to demonstrate the shape recovery effect, and finally, the applications of SMPs and SMPCs that are reinforced with fiber materials in aerospace are reviewed. SMPC hinges and booms are discussed in the part on components; the booms can be divided again into foldable SMPC truss booms, coilable SMPC truss booms and storable tubular extendible member (STEM) booms. In terms of SMPC structures, the solar array and deployable panel, reflector antenna and morphing wing are introduced in detail. Considering the factors of weight, recovery force and shock effect, SMPCs are expected to have great potential applications in aerospace.

https://iopscience.iop.org/article/10.1088/0964-1726/23/2/023001/pdf

Shape memory polymers and their composites in aerospace applications: a review

The thermomechanical properties of polyurethane-shape memory polymer (SMP) foams and the influence of shape-holding conditions on shape recovery were investigated experimentally. The results obtained can be summarized as follows. (1) By cooling the foam down to below the glass transition temperature Tg after compressive deformation above Tg, stress decreases and the deformed shape is fixed. By heating the shape-fixed foam up to above Tg under no load, the original shape is recovered. (2) The shape deformed above Tg is maintained for six months under no load at Tg− 60 K without depending on the maximum strain, and the original shape is recovered by heating thereafter. (3) If the deformed shape is held at high temperature, the original shape is not recovered. (4) The ratio of shape irrecovery increases in proportion to the holding strain, holding temperature and holding time.

The influence of shape-holding conditions on shape recovery of polyurethane-shape memory polymer foams

https://www.tandfonline.com/doi/pdf/10.1088/1468-6996/9/1/015009

Shape recovery and irrecoverable strain control in polyurethane shape-memory polymer

The thermomechanical properties of polyurethane shape memory polymer (SMP) foams were investigated experimentally. The results obtained can be summarized as follows. (1) By cooling the foam...

/pdf/shape-fixity-and-shape-recovery-of-polyurethane-shape-memory-2hrmtt6mpp.pdf

Shape fixity and shape recovery of polyurethane shape-memory polymer foams:

In order to describe the thermomechanical properties in shape memory polymer of polyurethane series, a thermomechanical constitutive model was developed. In order to describe the variation in mechanical properties due to the glass transition, coefficients in the model were expressed by a single exponential function of temperature. The proposed theory expressed well the thermomechanical properties of the material, such as shape fixity and shape recovery.

Thermomechanical Constitutive Modeling of Polyurethane-Series Shape Memory Polymer

In shape memory polymers, large strain can be fixed at low temperature and thereafter can be recovered at high temperature. If the shape memory polymer is held at high temperature for a long time, the secondary-shape forming with irrecoverable strain appears. The secondary-shape forming can be applied to a new simple method of fabricating shape-memory polymer elements. In the present paper, the influence of the strain-holding conditions on shape recovery and the secondary-shape forming in polyurethane-shape memory polymer is investigated by the tension test for film and the three-point bending test for sheet. The higher the shape-holding temperature and the longer the shape-holding time, the higher the rate of secondary-shape forming is. The equation to express the rate of secondary-shape forming is formulated.

Syunichi Hayashi

Papers

The influence of shape-holding conditions on shape recovery of polyurethane-shape memory polymer foams

Shape recovery and irrecoverable strain control in polyurethane shape-memory polymer

Shape fixity and shape recovery of polyurethane shape-memory polymer foams:

Thermomechanical Constitutive Modeling of Polyurethane-Series Shape Memory Polymer

Shape Recovery and Secondary-Shape Forming in Polyurethane-Shape Memory Polymer