Shape memory polymers (SMPs) belong to a class of smart polymers, which have drawn considerable research interest in last few years because of their applications in microelectromechanical systems, actuators, for self healing and health monitoring purposes, and in biomedical devices. Like in other fields of applications, SMP materials have been proved to be suitable substitutes to metallic ones because of their flexibility, biocompatibility and wide scope of modifications. The shape memory properties of SMPs polymers might surpass those of shape memory metallic alloys (SMAs). In addition to block copolymers, polymers blends and interpenetrating network structured SMP systems have been developed. The present review mainly highlights the recent progress in synthesis, characterization, evaluation, and proposed applications of SMPs and related composites.

Recent advances in shape memory polymers and composites : a review

We propose a simple theory describing the influence of nanoparticles on thermodynamics of binary polymer mixture. In particular, we consider the case in which nanoparticles preferentially segregate into one of the polymeric components. Depending on the particle radius Rp and the polymer degree of polymerization N, addition of nanoparticles can either promote or hinder mixing of the polymers. We calculate how the addition of nanoparticles shifts the spinodal of the polymer blend. These results help to improve understanding of recent simulations on the dynamics of polymer/particle mixtures.

Influence of Nanoparticles on Miscibility of Polymer Blends. A Simple Theory

A novel biodegradable multiblock poly(ester urethane) containing poly(L-lactic acid) and poly(butylene succinate) blocks

Artificial muscles composed of carbon nanotube yarns have previously demonstrated fast, large-angle rotations. Here, the authors infiltrate carbon nanotube yarns with a paraffin wax and polystyrene-based copolymer mixture, achieving stable 9,800 r.p.m. rotation without apparent oscillation.

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Hybrid carbon nanotube yarn artificial muscle inspired by spider dragline silk

Shape memory polymers (SMP) belong to the class of stimuli-responsive materials and have generated significant research interest. Their capability to retain an imposed, temporary shape and to recover the initial, permanent shape upon exposure to an external stimulus depends on the "functional determinants", which in simplistic terms, can be divided into structural/morphological and processing/environmental factors. The primary aim of the first part of this review is to reflect the knowledge about these fundamental relationships. In a next step, recent advances in shape memory polymer composites are summarized. In contrast to earlier reviews, studies on the impairment of shape memory properties through various factors, such as aging, compression and hibernation, lubricants, UV light and thermo-mechanical cycling, are extensively reviewed. Apart from summarizing the state-of-the-art in SMP research, recent progress is commented.

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Review on the Functional Determinants and Durability of Shape Memory Polymers

Damping performance of polymer blend/organic filler hybrid materials with selective compatibility

The influence of microscale fillers on ethylene–propylene rubbers (EPR) was examined with respect to their vibrational damping capacity and viscoelastic properties. The vibrational damping and dynamic mechanical properties of reinforced EPR were studied in systematic and comparative ways that reinforced the evidence of a direct relation between the vibrational damping loss factor and its mechanical damping loss factor. In this study, the sensitivity of the vibrational damping loss factor of reinforced EPR was quantified with respect to the variation in thickness, filler type, and filler content. Dynamic mechanical relaxation behaviors were also analyzed. The viscoelastic properties in terms of the storage modulus, loss modulus, mechanical damping loss factor, and frequency dependence of molecular relaxation showed interesting results with the filler types and compositions that had good correspondence with the vibrational damping behaviors. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3058–3066, 2001

Characterization of the vibrational damping loss factor and viscoelastic properties of ethylene-propylene rubbers reinforced with micro-scale fillers

We investigate the effects of the cross-sectional structure of a polyester-type polyurethane (pu)/polyvinylchloride (pvc) blend dope-coated nylon fabric on moisture permeability. The waterproof coating is applied by a one-sided wet-coagulation process. The blending of hydrophobic pvc to hydrophilic pu forms a three-layered cross-sectional structure—a pvc-rich micronetwork, a porous pu-rich layer, and the nylon fabric. As the blend ratio of pvc to pu increases, the moisture permeability (mp) and dew condensation (dc) of the coated fabrics improve. Compared to the pu homopolymer, the mp value of a pu/pvc blend in a weight ratio of 4:1 increases 1.18 times to 492 g/m2·h (JIS A-1 method) and 1.16 times to 815 g/m2·h (JIS B-1 method), but the dc value decreases one-fourth to 4.60 g/m2 · h. This gradient three-layered cross-sectional structure contributes to vapor transport properties.

Physical properties of polyurethane blend dope-coated fabrics

PROBLEM TO BE SOLVED: To provide an aqueous vibration-damping coating composition exhibiting high-degree vibration-damping performances. SOLUTION: The composition includes at least a matrix resin and a filler, where the filler includes an inorganic filler having a high aspect ratio, an inorganic filler having a low aspect ratio and an organic filler. The inorganic filler having a high aspect ratio has a weight-average aspect ratio of 10-200 and the content thereof based on all of the filler components is 35-70 wt.%. The inorganic filler having a low aspect ratio has a weight-average aspect ratio of 1-5 and the content thereof based on all of the filler components is 10-30 wt.%. The organic filler is an organic material which is in a crystalline state at a service temperature, has a melting point of 40-200°C and the content thereof based on all of the filler components is 3-40 wt.%. COPYRIGHT: (C)2010,JPO&INPIT

Aqueous vibration-damping coating composition

PROBLEM TO BE SOLVED: To obtain an organic hybrid vibration damping material having high damping effect and excellent stability and provide its production process. SOLUTION: The objective vibration damping material is composed of a composite material containing a material exhibiting piezoelectric dielectric and electrically conducting effects and an organic polymer matrix material and capable of converting the mechanical vibration energy and acoustic vibration energy supplied from external source into electric or dielectric energy. The material can be produced by homogeneousl mixing the material exhibiting piezoelectric, dielectric and electrically conducting effects with the organic polymer matrix material at or above room temperature and pressing or drawing at a high temperature. The material exhibiting piezoelectric, dielectric and electrically conducting effects is e.g. 4,4'-thiobis(3-methyl-6-t-butylphenol) and 2,2'-methylenebis(4-ethyl-6-t-butylphehol) and the organic polymer matrix material is e.g. acrylic rubber and chlorinated polyolefin.

Kiyohiro Inoue

Papers

Damping performance of polymer blend/organic filler hybrid materials with selective compatibility

Characterization of the vibrational damping loss factor and viscoelastic properties of ethylene-propylene rubbers reinforced with micro-scale fillers

Physical properties of polyurethane blend dope-coated fabrics

Aqueous vibration-damping coating composition

Organic hybrid vibration damping material and its production