Author
D Shimada
Bio: D Shimada is an academic researcher from Toyota. The author has contributed to research in topics: Shape-memory polymer. The author has an hindex of 1, co-authored 1 publications receiving 107 citations.
Topics: Shape-memory polymer
Papers
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TL;DR: In this article, the shape-fixed foam 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.
Abstract: 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.
111 citations
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TL;DR: A brief review on the current progress in stimuli-responsive shape memory materials can be found in this article, where the focus is on twofold, namely newly observed ones, and novel applications with great potential at present and in near future.
864 citations
TL;DR: In this article, the authors examined the research in shape memory polymers (SMPs) composites and blends achieved by numerous research groups around the world, mainly for five aims: (1) to improve shape recovery stress and mechanical properties; (2) to decrease shape recovery induction time by increasing thermal conductivity; (3) to create new polymer/polymer blends with shape-memory effect (SME); (4) to tune switch temperature, mechanical properties, and biomedical properties of SMPs; (5) to fabricate shape memory materials sensitive to electricity,
Abstract: Shape memory polymers (SMPs) are a kind of very important smart polymers. In order to improve the properties or obtain new functions of SMPs, SMP composites and blends are prepared. We thoroughly examine the research in SMP composites and blends achieved by numerous research groups around the world. The preparation of SMPs composites and blends is mainly for five aims: (1) to improve shape recovery stress and mechanical properties; (2) to decrease shape recovery induction time by increasing thermal conductivity; (3) to create new polymer/polymer blends with shape-memory effect (SME); (4) to tune switch temperature, mechanical properties, and biomedical properties of SMPs; (5) to fabricate shape memory materials sensitive to electricity, magnetic, light and moisture. The trend of SMP composite development is discussed. SMP composites and blends exhibit novel properties that are different from the conventional SMPs and thus can be utilized in various applications.
525 citations
TL;DR: In this paper, a review of the literature on shape memory polymers (SMPs) is presented, and it is concluded that covalently crosslinked glassy thermosets appear to be better SMP candidates because of their intrinsically higher modulus, greater thermal and chemical stability, higher shape fixity and recovery, and possibly their longer cycle life.
Abstract: Many applications ranging from biomedical to aerospace have been proposed for the use of shape memory polymers (SMPs). To optimize SMPs properties for appropriately targeting such wide-spreading application requirements, it becomes necessary to understand the structure/property relationships in SMPs. The literature was reviewed and the recent advances made in the development of SMPs were determined to establish guidelines for composition and structure considerations for designing SMPs with targeted chemical, physical, and shape memory (SM) properties. It was concluded that covalently crosslinked glassy thermosets appear to be better SMP candidates because of their intrinsically higher modulus, greater thermal and chemical stability, higher shape fixity and recovery, and possibly their longer cycle life. However, material design allows for reaching comparable or better properties for all classes of SMPs. This emphasizes that optimization of SMPs requires application-specific molecular, structural, and geometrical design. Current techniques for improving stress recovery and cycle time, which compared to shape memory alloys are the two main limitations of SMPs, are extensively discussed. Understanding the relationships between the composition and structure of an SMP and its SM properties as well as its limitations enables one to better define the development areas for high performance SMPs. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
383 citations
TL;DR: Based on the working mechanisms, a systematic literature review is logically presented to reveal that the thermo- and chemo- responsive shape memory effects (SMEs) are not the special phenomena of some particular polymers, but intrinsic features of most polymers as discussed by the authors.
Abstract: Based on the working mechanisms, a systematic literature review is logically presented to reveal that the thermo- and chemo- responsive shape memory effects (SMEs) are not the special phenomena of some particular polymers, but intrinsic features of most polymers (if not all). Subsequently, referring to the most recent experimental results and their theoretical origins, we reveal the fundamentals on the optimization of the SME in polymers and the approaches to design/synthesize polymeric materials with tailored features.
258 citations
TL;DR: In this article, a 3D thermoviscoelastic model is proposed to represent the thermomechanical behavior of shape memory polymers, which is based on a physical understanding of the material behavior and a mechanical interpretation of the stress-strain-temperature changes observed during thermal loading.
Abstract: A 3D thermoviscoelastic model is proposed to represent the thermomechanical behavior of shape memory polymers. The model is based on a physical understanding of the material behavior and a mechanical interpretation of the stress–strain–temperature changes observed during thermomechanical loading. The model is thermodynamically motivated and is formulated in a finite strain framework in order to account for large strain deformations. Model predictions capture critical features of shape memory polymer deformation and, in some cases, provide very favorable comparisons with experimental results. POLYM. ENG. SCI. 46:486–492, 2006. © 2006 Society of Plastics Engineers.
254 citations