Free Recovery Effects of Shape-Memory Polymers for Cardiovascular Stents

2005 ◽  
Vol 898 ◽  
Author(s):  
Christopher Michael Yakacki ◽  
Robin Shandas ◽  
Craig Lanning ◽  
Ken Gall
Keyword(s):  
Glass Transition ◽  
Shape Memory ◽  
Polymer Networks ◽  
Transition Temperatures ◽  
Poly Ethylene Glycol ◽  
Glass Transition Temperatures ◽  
Cardiovascular Stents ◽  
Geometrical Features ◽  
Poly Ethylene ◽  
Free Strain

AbstractThe shape-memory effect was examined in polymer stents intended for cardiovascular applications. Four polymer networks were synthesized from poly(ethylene glycol) dimethacrylate and tert-butyl acrylate with 10 wt% and 20 wt% crosslinker, and with glass transition temperatures (Tg) of 52°C and 55°C. Solid and 50% porous stents were manufactured and tested for free strain recoverability at temperatures at or just above 37°C. Stents with lower glass transition temperatures and a higher degree of crosslinking recovered faster than their counterparts. Lower deformation (packaging) temperatures and higher recovery temperatures induce more rapid recovery. The presence of geometrical features, such as pores, initiated recovery sooner, but had negligible influence on overall recovery.

scholarly journals Epoxy Resin Composite Bilayers with Triple-Shape Memory Effect

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Xixi Li ◽  
Yaofeng Zhu ◽  
Yubing Dong ◽  
Meng Liu ◽  
Qingqing Ni ◽  
...  
Keyword(s):  
Glass Transition ◽  
Electron Microscope ◽  
Shape Memory ◽  
Memory Effects ◽  
Epoxy Composites ◽  
Transition Temperatures ◽  
Glass Transition Temperatures ◽  
Shape Memory Effects ◽  
Triple Shape Memory ◽  
Nanosilica Particles

Triple-shape memory epoxy composites with bilayer structures of well-separated glass transition temperatures have been successfully prepared. The different glass transition temperatures of the epoxy composites were obtained by physically incorporating various amounts of nanosilica particles, which were introduced into the epoxy by utilizing polyethylene glycol. A scanning electron microscope and a transmission electron microscope were used to analyze the dispersibility of the nanosilica particles. The effects of nanosilica particles on the mechanical properties as well as on the dual-shape memory effects (DSME) and triple-shape memory effects (TSME) of the nanocomposites were studied. The nanosilica particles were homogenously dispersed in the matrix and well incorporated into the epoxy matrix. The resulting nanocomposites exhibited excellent TSME, and their shape fixity properties were significantly improved by nanosilica particles.

scholarly journals Cyclohexyl-substituted poly(phosphonate)-copolymers with adjustable glass transition temperatures

2016 ◽  
Vol 7 (17) ◽  
pp. 2934-2937 ◽  
Author(s):  
Thomas Wolf ◽  
Johannes Naß ◽  
Frederik R. Wurm
Keyword(s):  
Glass Transition ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Transition Temperatures ◽  
Glass Transition Temperatures ◽  
Anionic Ring ◽  
Poly Ethylene

2-Cyclohexyl-2-oxo-1,3,2-dioxaphospholane (cyHexPPn), a new monomer for the anionic ring-opening polymerization to poly(ethylene alkyl phosphonate)s is presented.

Body temperature-responsive two-way and moisture-responsive one-way shape memory behaviors of poly(ethylene glycol)-based networks

2017 ◽  
Vol 8 (25) ◽  
pp. 3833-3840 ◽  
Author(s):  
Guang Yang ◽  
Xueyang Liu ◽  
Alfred Iing Yoong Tok ◽  
Vitali Lipik
Keyword(s):  
Free Radical ◽  
Ethylene Glycol ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Networks ◽  
Poly Ethylene Glycol ◽  
Thermally Induced ◽  
Temperature Responsive ◽  
Shape Memory Effects ◽  
Poly Ethylene

In this work, crosslinked shape-memory polymer networks were prepared by thermally induced free-radical polymerizations of methacrylate-terminated poly(ethylene glycol) (PEG) and n-butyl acrylate (BA), which integrate thermal-responsive two-way and moisture-responsive one-way shape memory effects (SME).

Shape memory behavior and mechanism of poly(methyl methacrylate) polymer networks in the presence of star poly(ethylene glycol)

RSC Advances ◽  
2014 ◽  
Vol 4 (37) ◽  
pp. 19273 ◽  
Author(s):  
Xingjian Li ◽  
Tuo Liu ◽  
Yaru Wang ◽  
Yi Pan ◽  
Zhaohui Zheng ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Methyl Methacrylate ◽  
Shape Memory ◽  
Polymer Networks ◽  
Poly Ethylene Glycol ◽  
Poly Methyl Methacrylate ◽  
Shape Memory Behavior ◽  
Poly Ethylene

A novel shape memory polymer based on conetworks

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Zonghui Li ◽  
Yi Pan ◽  
Peng Zhang ◽  
Zhaohui Zheng ◽  
Xiaobin Ding ◽  
...  
Keyword(s):  
Glass Transition ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Recovery Ratio ◽  
Modulus Ratio ◽  
Poly Ethylene Glycol ◽  
Shape Memory Properties ◽  
Shape Memory Effects ◽  
Shape Memory Materials ◽  
Poly Ethylene

AbstractA novel shape memory polymer based on conetworks (CNs) was synthesized. These conetworks consisting of poly(methyl methacrylate) and poly (ethylene glycol) diacrylates showed excellent shape-memory properties with a recovery ratio of nearly 100%. Moreover, different shape memory effects were discovered in different mediums due to their amphiphilic properties. In addition, a large storage modulus ratio above and below the glass transition temperature(Eratio), which probably means excellent shape memory effect, were obtained due to the designed CN structure whether crystallization existed or not. It is quite different from the traditional methods to achieve large Eratio values. The versatility of shapememory conetworks potentially provides us a new route to prepare shape memory materials.

scholarly journals Depression of glass transition temperatures of polymer networks by diluents

1983 ◽  
Vol 16 (2) ◽  
pp. 244-249 ◽  
Author(s):  
Genit ten Brinke ◽  
Frank E. Karasz ◽  
T. S. Ellis
Keyword(s):  
Glass Transition ◽  
Polymer Networks ◽  
Transition Temperatures ◽  
Glass Transition Temperatures

scholarly journals Complexation of poly(ethylene glycol) with poly(ethyl methacrylate-co-N-vinyl-2-pyrrolidone) gel based on hydrogen bonds

2013 ◽  
Vol 15 (3) ◽  
pp. 85-90 ◽  
Author(s):  
Guoqin Liu
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Complex Formation ◽  
Hydrogen Bonds ◽  
Ethylene Glycol ◽  
Amorphous Phase ◽  
Poly Ethylene Glycol ◽  
Glass Transition Temperatures ◽  
Ethyl Methacrylate ◽  
Poly Ethylene

Abstract The complexes of poly(ethyl methacrylate-co-N-vinyl-2-pyrrolidone) (P(EMA-co-VP)) gel with poly- (ethylene glycol) (PEG) stabilized by the hydrogen bonds were prepared. It was found that both the concentration and the molecular weight of PEG have a strong effect on the P(EMA-co-VP) gel. When PEG was introduced into the P(EMA-co-VP) gel, the glass transition temperatures (Tg) of the complexes decreases with the decreasing of PEG molecular weight. In such a system, the maximum molecular weight of PEG required for the complex formation is no more than 2000, and P(EMA-co-VP)/PEG complexes are a homogeneous amorphous phase, which was studied by FTIR, XRD, TEM, and DSC.

Multiple shape memory polymers for self-deployable device

RSC Advances ◽  
2016 ◽  
Vol 6 (56) ◽  
pp. 50581-50586 ◽  
Author(s):  
Shuyun Zhuo ◽  
Gongzheng Zhang ◽  
Xianqi Feng ◽  
Haoyang Jiang ◽  
Jinli Shi ◽  
...  
Keyword(s):  
Glass Transition ◽  
Shape Memory ◽  
Shape Memory Polymers ◽  
Transition Temperatures ◽  
Glass Transition Temperatures

Three-segments MH copolymers with well-separated glass transition temperatures can subsequently change their shapes in a pre-defined way.

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