SMP Technologies Inc.

Tokyo, Japan

SMP Technologies Inc.

Tokyo, Japan
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Pieczyska E.A.,Polish Institute of Fundamental Technological Research | Staszczak M.,Polish Institute of Fundamental Technological Research | Maj M.,Polish Institute of Fundamental Technological Research | Kowalczyk-Gajewska K.,Polish Institute of Fundamental Technological Research | And 4 more authors.
Smart Materials and Structures | Year: 2016

This paper presents experimental and modeling results of the effects of thermomechanical couplings occurring in a polyurethane shape memory polymer (SMP) subjected to tension at various strain rates within large strains. The SMP mechanical curves, recorded using a testing machine, and the related temperature changes, measured in a contactless manner using an IR camera, were used to investigate the polymer deformation process at various loading stages. The effects of thermomechanical couplings allowed the determination of the material yield point in the initial loading stage, the investigation of nucleation and development of the strain localization at larger strains and the estimation of the effects of thermoelastic behavior during the unloading process. The obtained stress-strain and thermal characteristics, the results of the dynamic mechanical analysis and estimated values of the shape fixity and shape recovery parameters confirmed that the shape memory polymer (T g = 45 °C) is characterized by good mechanical and shape memory properties, as well as high sensitivity to the strain rate. The mechanical response of the SMP subjected to tension was simulated using the finite element method and applying the large strain, two-phase model. Strain localization observed in the experiment was well reproduced in simulations and the temperature spots were correlated with the accumulated viscoplastic deformation of the SMP glassy phase. © 2016 IOP Publishing Ltd.


Pieczyska E.A.,Polish Institute of Fundamental Technological Research | Maj M.,Polish Institute of Fundamental Technological Research | Kowalczyk-Gajewska K.,Polish Institute of Fundamental Technological Research | Staszczak M.,Polish Institute of Fundamental Technological Research | And 4 more authors.
Journal of Materials Engineering and Performance | Year: 2014

Multifunctional new material - polyurethane shape memory polymer (PU-SMP) - was subjected to tension carried out at room temperature at various strain rates. The influence of effects of thermomechanical couplings on the SMP mechanical properties was studied, based on the sample temperature changes, measured by a fast and sensitive infrared camera. It was found that the polymer deformation process strongly depends on the strain rate applied. The initial reversible strain is accompanied by a small drop in temperature, called thermoelastic effect. Its maximal value is related to the SMP yield point and increases upon increase of the strain rate. At higher strains, the stress and temperature significantly increase, caused by reorientation of the polymer molecular chains, followed by the stress drop and its subsequent increase accompanying the sample rupture. The higher strain rate, the higher stress, and temperature changes were obtained, since the deformation process was more dynamic and has occurred in almost adiabatic conditions. The constitutive model of SMP valid in finite strain regime was developed. In the proposed approach, SMP is described as a two-phase material composed of hyperelastic rubbery phase and elastic-viscoplastic glassy phase, while the volume content of phases is specified by the current temperature. © 2014 ASM International.


Tobushi H.,Aichi Institute of Technology | Hayashi S.,SMP Technologies Inc. | Pieczyska E.,Polish Academy of Sciences | Date K.,Ochiai Nexus Co. | Nishimura Y.,Aichi Institute of Technology
Materials Science Forum | Year: 2011

The SMC belt composed of two kinds of SMAs and SMP was fabricated and the three-way movement and recovery force in bending were investigated. The results obtained can be summarized as follows. (1) The three-way bending movement was achived during heating and cooling based on the characteristics of the SMA tapes and the SMP sheet. (2) The recovery force increased during heating and decreased during cooling. The recovery force was evaluated by the proposed simple model. © (2011) Trans Tech Publications, Switzerland.


Tobushi H.,Aichi Institute of Technology | Hayashi S.,SMP Technologies Inc. | Pieczyska E.,Polish Academy of Sciences | Date K.,Ochiai Nexus Co. | Nishimura Y.,Aichi Institute of Technology
Archives of Mechanics | Year: 2011

The SMC belt composed of two kinds of SMAs with different phase transformation temperatures and SMP, was fabricated and the three-way (reciprocating) movement and recovery force in bending actuation were investigated. The results obtained can be summarized as follows. 1) The three-way bending movement was achived during heating and cooling, based on the characteristics of the SMA tapes and the SMP tape. 2) The recovery force decreased at first and increased thereafter during heating and decreased during cooling. The recovery force was roughly estimated by the proposed model. 3) The development and application of multi-functional SMCs with simple structure for three-dimensional actuators are highly expected. Copyright © 2011 by IPPT PAN.


Nishikawa M.,Kyoto University | Matsuda S.,Kyoto University | Hayashi S.,SMP Technologies Inc. | Hojo M.,Kyoto University | Matsuda N.,Kyoto University
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2016

The present study attempted to model dynamic viscoelastic properties of polyurethane block copolymers to understand the effect of molecular properties on shape change functions of the materials. For this purpose, we proposed dynamic viscoelastic simulations to obtain stress response in frequency domain against oscillating strain history, using molecular mechanics models consisting of hard and soft segments. The simulations employed coarse-grained bead-spring model based on the force fields given by bond-stretch potential for covalent bonding and Lennard-Jones potential for intermolecular interaction. The rigidity and aggregability of hard segments (HS) were represented by varying the molecular mechanics parameters for these force fields. The proposed simulation could reproduce a clear glass transition from glassy state to rubbery state in frequency domain. The rigidity of HS increased the stiffness at glassy state and tanδ as an indicator of energy dissipation as well, which led to the sharpening of glass transition range. The aggregability of HS increased the stiffness at rubbery state and it also shifted glass transition point to a higher frequency and broadened glass transition range by changing the mobility of soft segments (SS). Finally, a spherically aggregated HS domain was found to degrade shape change functions from the viewpoint of storage modulus. We concluded that the shape change functions of the materials were closely related to energy storage ability of HS and mobility of SS, and that the aggregability of HS yielded by hydrogen bonding in polyurethanes plays an important role in shape change functions. ©2016 The Society of Materials Science.


Kuriyagawa M.,Kanazawa University | Kawamura T.,Kanazawa University | Hayashi S.,SMP Technologies Inc. | Nitta K.-H.,Kanazawa University
Journal of Materials Science | Year: 2011

The mechanical yielding behavior of the shape memory polyurethane (SMP) and its composite samples were investigated to verify the effect of addition of hindered phenol. The composite samples were prepared using SMP as matrix and hindered phenol (AO-80) as filler, and then tensile tests were carried out at a range of temperatures and with different fixed crosshead speeds. According to the tensile data at 25 °C, the yield stress was increased by adding AO-80. In terms of the Eyring theory, the activation volume of deformation units decreased with increase of the amount of AO-80 added. This is because the packing of the hard segments is enhanced by addition of AO-80. Consequently, it was suggested that the yield process is caused by the rotation of hard segment domains within the deformed plastic domains composed of glassy soft segments. © Springer Science+Business Media, LLC 2010.


Kuriyagawa M.,Kanazawa University | Kawamura T.,Kanazawa University | Hayashi S.,SMP Technologies Inc. | Nitta K.-H.,Kanazawa University
Journal of Applied Polymer Science | Year: 2010

Reinforcement of polyurethane-based shape memory polymer materials was investigated by adding hindered phenol compounds and silica particles. According to dynamic mechanical analysis, these fillers had no effect on the glass transition temperature and the activation energy of soft segments, indicating that the fillers have no ability to influence the molecular mobility of soft segments. It was found from the tensile tests that the yield stress was increased primarily by addition of the hindered phenols rather than the silica particles, whereas Young's modulus was enhanced by the silica particles rather than the hindered phenols. VC 2010 Wile y Periodicals, Inc.


Tobushi H.,Aichi Institute of Technology | Hayashi S.,SMP Technologies Inc. | Sugimoto Y.,Aichi Institute of Technology | Date K.,Aichi Institute of Technology
Materials Science Forum | Year: 2010

The shape memory composite (SMC) with shape memory alloy (SMA) and shape memory polymer (SMP) was fabricated, and the two-way bending deformation and recovery force were investigated. The results obtained can be summarized as follows. (1) Two kinds of SMA tapes which show the shape memory effect and superelasticity were heat-treated to memorize the round shape, respectively. The shape-memorized round SMA tapes were sandwiched between the SMP sheets, and the SMC belt was fabricated. (2) The two-way bending deformation with an angle of 56 degrees is observed during heating and cooling. (3) If the SMC belt is heated and cooled by keeping the form, recovery force increases during heating and decreases during cooling. © (2010) Trans Tech Publications.


Patent
SMP Technologies Inc. | Date: 2012-12-28

A polyurethane foam having excellent shape-following properties, which exhibits favorable comfort when worn on the human body, both during movement and at rest. The polyurethane foam contains a toluene diisocyanate and a polyether polyol as the main components, has a glass transition temperature, defined as the temperature corresponding with the peak value of the loss tangent, of not less than 0 C. and not more than 40 C., and in the temperature range from not less than 0 C. to not more than 40 C., the loss tangent in the frequency range from not less than 0.1 Hz to not more than 100 Hz is 0.4 or greater, and the average value of the loss tangent in the frequency range from not less than 0.1 Hz to not more than 1 Hz is not greater than the average value of the loss tangent in the frequency range from not less than 10 Hz to not more than 100 Hz.


Patent
SMP Technologies Inc. | Date: 2016-01-28

The provision of a film which is comfortable when worn on the human body, both when the body is at rest as well as when the body is in motion and which is also capable of reinforcing the movement of the human body, particularly during exercise, as well as a composite fabric containing said film. A composite fabric composed of a fabric, as well as a synthetic resin layer which covers part of the surface of at least one side of said fabric, wherein the synthetic resin layer is composed primarily of a polyurethane elastomer produced by via the polymerization of a bifunctional diisocyanate, bifunctional polyol and bifunctional chain extender using the pre-polymer method at a molar ratio of 2.00 to 1.10:1.00:1.00 to 0.10, and the coverage ratio of the synthetic resin layer relative to the surface of the fabric ranges from 10 to 90% (inclusive).

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