The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Shan-hui Hsu - One of the best experts on this subject based on the ideXlab platform.
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Preparation, Characterization, and Mechanism for Biodegradable and Biocompatible Polyurethane Shape Memory Elastomers
2017Co-Authors: Yuchun Chien, U-ser Jeng, Weitsung Chuang, Shan-hui HsuAbstract:Thermally induced shape memory is an attractive feature of certain functional materials. Among the shape memory polymers, shape memory elastomers (SMEs) especially those with biodegradability have great potential in the biomedical field. In this study, we prepared waterborne biodegradable polyurethane SME based on poly(ε-caprolactone) (PCL) Oligodiol and poly(l-lactic acid) (PLLA) Oligodiol as the mixed soft segments. The ratio of the soft segments in polyurethanes was optimized for shape memory behavior. The thermally induced shape memory mechanism of the series of polyurethanes was clarified using differential scanning calorimeter (DSC), X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS). In particular, the in situ SAXS measurements combined with shape deformation processes were employed to examine the stretch-induced (oriented) crystalline structure of the polyurethanes and to elucidate the unique mechanism for shape memory properties. The polyurethane with optimized PLLA crystalline segments showed a diamond-shape two-dimensional SAXS pattern after being stretched, which gave rise to better shape fixing and shape recovery. The shape memory behavior was further tested in 37 °C water. The biodegradable polyurethane comprising 38 wt % PCL segments and 25 wt % PLLA segments and synthesized at a relatively lower temperature by the waterborne procedure showed ∼100% shape recovery in 37 °C water. The biodegradable polyurethane SME also demonstrated good endothelial cell viability as well as low platelet adhesion/activation. We conclude that the waterborne biodegradable polyurethane SME possesses a unique thermally induced shape memory mechanism and may have potential applications in making shape memory biodegradable stents or scaffolds
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Synthesis of Thermoresponsive Amphiphilic Polyurethane Gel as a New Cell Printing Material near Body Temperature.
ACS applied materials & interfaces, 2015Co-Authors: Yi-chun Tsai, U-ser Jeng, Wen-chi Chang, Shan-hui HsuAbstract:Waterborne polyurethane (PU) based on poly(e-caprolactone) (PCL) diol and a second Oligodiol containing amphiphilic blocks was synthesized in this study. The microstructure was characterized by dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and rheological measurement of the PU dispersion. The surface hydrophilicity measurement, infrared spectroscopy, wide-angle X-ray diffraction, mechanical and thermal analyses were conducted in solid state. It was observed that the presence of a small amount of amphiphilic blocks in the soft segment resulted in significant changes in microstructure. When 90 mol % PCL diol and 10 mol % amphiphilic blocks of poly(l-lactide)–poly(ethylene oxide) (PLLA–PEO) diol were used as the soft segment, the synthesized PU had a water contact angle of ∼24° and degree of crystallinity of ∼14%. The dispersion had a low viscosity below room temperature. As the temperature was raised to body temperature (37 °C), the dispersion rapidly (∼170 s) underwent sol–gel transi...
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Synthesis of Thermoresponsive Amphiphilic Polyurethane Gel as a New Cell Printing Material near Body Temperature
2015Co-Authors: Yi-chun Tsai, U-ser Jeng, Wen-chi Chang, Shan-hui HsuAbstract:Waterborne polyurethane (PU) based on poly(ε-caprolactone) (PCL) diol and a second Oligodiol containing amphiphilic blocks was synthesized in this study. The microstructure was characterized by dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and rheological measurement of the PU dispersion. The surface hydrophilicity measurement, infrared spectroscopy, wide-angle X-ray diffraction, mechanical and thermal analyses were conducted in solid state. It was observed that the presence of a small amount of amphiphilic blocks in the soft segment resulted in significant changes in microstructure. When 90 mol % PCL diol and 10 mol % amphiphilic blocks of poly(l-lactide)–poly(ethylene oxide) (PLLA–PEO) diol were used as the soft segment, the synthesized PU had a water contact angle of ∼24° and degree of crystallinity of ∼14%. The dispersion had a low viscosity below room temperature. As the temperature was raised to body temperature (37 °C), the dispersion rapidly (∼170 s) underwent sol–gel transition with excellent gel modulus (G′ ≈ 6.5 kPa) in 20 min. PU dispersions with a solid content of 25–30% could be easily mixed with cells in sol state, extruded by a 3D printer, and deposited layer by layer as a gel. Cells remained alive and proliferating in the printed hydrogel scaffold. We expect that the development of novel thermoresponsive PU system can be used as smart injectable hydrogel and applied as a new type of bio-3D printing ink
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Water-based synthesis and processing of novel biodegradable elastomers for medical applications
Journal of materials chemistry. B, 2014Co-Authors: Shan-hui Hsu, U-ser Jeng, Kun-che Hung, Ying-yi Lin, Hsi-yi Yeh, Shenghong A. Dai, Jui Che LinAbstract:Biodegradable elastomers in the form of polyurethane nanoparticles (NPs) were successfully synthesized based on the combinations of two hydrolysis-prone polyester diols by a green water-based process. The anionic nature of the polymers successfully rendered polyurethane NPs (30–50 nm) consisting of approximately 200–300 polymer chains. The mechanical properties and degradation rate could be adjusted by the types and ratios of the component Oligodiols in the soft segment. We demonstrated the feasibility using these biodegradable NPs as building blocks to generate self-assembled morphologies in nanometric, micrometric, or bulk scale, bearing excellent elasticity and biocompatibility. The elastic NPs and their various assembled forms represent a series of smart biodegradable elastomers with potential medical applications.
U-ser Jeng - One of the best experts on this subject based on the ideXlab platform.
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Preparation, Characterization, and Mechanism for Biodegradable and Biocompatible Polyurethane Shape Memory Elastomers
2017Co-Authors: Yuchun Chien, U-ser Jeng, Weitsung Chuang, Shan-hui HsuAbstract:Thermally induced shape memory is an attractive feature of certain functional materials. Among the shape memory polymers, shape memory elastomers (SMEs) especially those with biodegradability have great potential in the biomedical field. In this study, we prepared waterborne biodegradable polyurethane SME based on poly(ε-caprolactone) (PCL) Oligodiol and poly(l-lactic acid) (PLLA) Oligodiol as the mixed soft segments. The ratio of the soft segments in polyurethanes was optimized for shape memory behavior. The thermally induced shape memory mechanism of the series of polyurethanes was clarified using differential scanning calorimeter (DSC), X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS). In particular, the in situ SAXS measurements combined with shape deformation processes were employed to examine the stretch-induced (oriented) crystalline structure of the polyurethanes and to elucidate the unique mechanism for shape memory properties. The polyurethane with optimized PLLA crystalline segments showed a diamond-shape two-dimensional SAXS pattern after being stretched, which gave rise to better shape fixing and shape recovery. The shape memory behavior was further tested in 37 °C water. The biodegradable polyurethane comprising 38 wt % PCL segments and 25 wt % PLLA segments and synthesized at a relatively lower temperature by the waterborne procedure showed ∼100% shape recovery in 37 °C water. The biodegradable polyurethane SME also demonstrated good endothelial cell viability as well as low platelet adhesion/activation. We conclude that the waterborne biodegradable polyurethane SME possesses a unique thermally induced shape memory mechanism and may have potential applications in making shape memory biodegradable stents or scaffolds
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Synthesis of Thermoresponsive Amphiphilic Polyurethane Gel as a New Cell Printing Material near Body Temperature.
ACS applied materials & interfaces, 2015Co-Authors: Yi-chun Tsai, U-ser Jeng, Wen-chi Chang, Shan-hui HsuAbstract:Waterborne polyurethane (PU) based on poly(e-caprolactone) (PCL) diol and a second Oligodiol containing amphiphilic blocks was synthesized in this study. The microstructure was characterized by dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and rheological measurement of the PU dispersion. The surface hydrophilicity measurement, infrared spectroscopy, wide-angle X-ray diffraction, mechanical and thermal analyses were conducted in solid state. It was observed that the presence of a small amount of amphiphilic blocks in the soft segment resulted in significant changes in microstructure. When 90 mol % PCL diol and 10 mol % amphiphilic blocks of poly(l-lactide)–poly(ethylene oxide) (PLLA–PEO) diol were used as the soft segment, the synthesized PU had a water contact angle of ∼24° and degree of crystallinity of ∼14%. The dispersion had a low viscosity below room temperature. As the temperature was raised to body temperature (37 °C), the dispersion rapidly (∼170 s) underwent sol–gel transi...
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Synthesis of Thermoresponsive Amphiphilic Polyurethane Gel as a New Cell Printing Material near Body Temperature
2015Co-Authors: Yi-chun Tsai, U-ser Jeng, Wen-chi Chang, Shan-hui HsuAbstract:Waterborne polyurethane (PU) based on poly(ε-caprolactone) (PCL) diol and a second Oligodiol containing amphiphilic blocks was synthesized in this study. The microstructure was characterized by dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and rheological measurement of the PU dispersion. The surface hydrophilicity measurement, infrared spectroscopy, wide-angle X-ray diffraction, mechanical and thermal analyses were conducted in solid state. It was observed that the presence of a small amount of amphiphilic blocks in the soft segment resulted in significant changes in microstructure. When 90 mol % PCL diol and 10 mol % amphiphilic blocks of poly(l-lactide)–poly(ethylene oxide) (PLLA–PEO) diol were used as the soft segment, the synthesized PU had a water contact angle of ∼24° and degree of crystallinity of ∼14%. The dispersion had a low viscosity below room temperature. As the temperature was raised to body temperature (37 °C), the dispersion rapidly (∼170 s) underwent sol–gel transition with excellent gel modulus (G′ ≈ 6.5 kPa) in 20 min. PU dispersions with a solid content of 25–30% could be easily mixed with cells in sol state, extruded by a 3D printer, and deposited layer by layer as a gel. Cells remained alive and proliferating in the printed hydrogel scaffold. We expect that the development of novel thermoresponsive PU system can be used as smart injectable hydrogel and applied as a new type of bio-3D printing ink
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Water-based synthesis and processing of novel biodegradable elastomers for medical applications
Journal of materials chemistry. B, 2014Co-Authors: Shan-hui Hsu, U-ser Jeng, Kun-che Hung, Ying-yi Lin, Hsi-yi Yeh, Shenghong A. Dai, Jui Che LinAbstract:Biodegradable elastomers in the form of polyurethane nanoparticles (NPs) were successfully synthesized based on the combinations of two hydrolysis-prone polyester diols by a green water-based process. The anionic nature of the polymers successfully rendered polyurethane NPs (30–50 nm) consisting of approximately 200–300 polymer chains. The mechanical properties and degradation rate could be adjusted by the types and ratios of the component Oligodiols in the soft segment. We demonstrated the feasibility using these biodegradable NPs as building blocks to generate self-assembled morphologies in nanometric, micrometric, or bulk scale, bearing excellent elasticity and biocompatibility. The elastic NPs and their various assembled forms represent a series of smart biodegradable elastomers with potential medical applications.
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characterization of biodegradable polyurethane nanoparticles and thermally induced self assembly in water dispersion
ACS Applied Materials & Interfaces, 2014Co-Authors: Chunwei Ou, Chiuhun Su, U-ser JengAbstract:Waterborne polyurethanes (PU) with different compositions of biodegradable Oligodiols as the soft segment were synthesized as nanoparticles (NPs) in this study. Using dynamic light scattering (DLS), multiangle light scattering (MALS), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS), we demonstrated that these NPs were compact spheres with different shape factors. The temperature-dependent swelling of the PU NPs in water was distinct. In particular, PU NPs with 80 mol % polycaprolactone (PCL) diol and 20 mol % poly(l-lactide) (PLLA) diol as the soft segment had significant swelling (∼450%) at 37 °C. This was accompanied by a sol–gel transition observed in about 2 min for the NP dispersion. The thermally induced swelling and self-assembly of these NPs were associated with the secondary force (mainly hydrogen bonding) and degree of crystallinity, which depended on the soft segment compositions. The thermo-responsiveness of the PU NPs with mixed biodegradable Oligodiols may be ...
Ser U Jeng - One of the best experts on this subject based on the ideXlab platform.
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preparation characterization and mechanism for biodegradable and biocompatible polyurethane shape memory elastomers
ACS Applied Materials & Interfaces, 2017Co-Authors: Yuchun Chien, Weitsung Chuang, Ser U JengAbstract:Thermally induced shape memory is an attractive feature of certain functional materials. Among the shape memory polymers, shape memory elastomers (SMEs) especially those with biodegradability have great potential in the biomedical field. In this study, we prepared waterborne biodegradable polyurethane SME based on poly(e-caprolactone) (PCL) Oligodiol and poly(l-lactic acid) (PLLA) Oligodiol as the mixed soft segments. The ratio of the soft segments in polyurethanes was optimized for shape memory behavior. The thermally induced shape memory mechanism of the series of polyurethanes was clarified using differential scanning calorimeter (DSC), X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS). In particular, the in situ SAXS measurements combined with shape deformation processes were employed to examine the stretch-induced (oriented) crystalline structure of the polyurethanes and to elucidate the unique mechanism for shape memory properties. The polyurethane with optimized PLLA crystalline segm...
Yuchun Chien - One of the best experts on this subject based on the ideXlab platform.
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preparation characterization and mechanism for biodegradable and biocompatible polyurethane shape memory elastomers
ACS Applied Materials & Interfaces, 2017Co-Authors: Yuchun Chien, Weitsung Chuang, Ser U JengAbstract:Thermally induced shape memory is an attractive feature of certain functional materials. Among the shape memory polymers, shape memory elastomers (SMEs) especially those with biodegradability have great potential in the biomedical field. In this study, we prepared waterborne biodegradable polyurethane SME based on poly(e-caprolactone) (PCL) Oligodiol and poly(l-lactic acid) (PLLA) Oligodiol as the mixed soft segments. The ratio of the soft segments in polyurethanes was optimized for shape memory behavior. The thermally induced shape memory mechanism of the series of polyurethanes was clarified using differential scanning calorimeter (DSC), X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS). In particular, the in situ SAXS measurements combined with shape deformation processes were employed to examine the stretch-induced (oriented) crystalline structure of the polyurethanes and to elucidate the unique mechanism for shape memory properties. The polyurethane with optimized PLLA crystalline segm...
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Preparation, Characterization, and Mechanism for Biodegradable and Biocompatible Polyurethane Shape Memory Elastomers
2017Co-Authors: Yuchun Chien, U-ser Jeng, Weitsung Chuang, Shan-hui HsuAbstract:Thermally induced shape memory is an attractive feature of certain functional materials. Among the shape memory polymers, shape memory elastomers (SMEs) especially those with biodegradability have great potential in the biomedical field. In this study, we prepared waterborne biodegradable polyurethane SME based on poly(ε-caprolactone) (PCL) Oligodiol and poly(l-lactic acid) (PLLA) Oligodiol as the mixed soft segments. The ratio of the soft segments in polyurethanes was optimized for shape memory behavior. The thermally induced shape memory mechanism of the series of polyurethanes was clarified using differential scanning calorimeter (DSC), X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS). In particular, the in situ SAXS measurements combined with shape deformation processes were employed to examine the stretch-induced (oriented) crystalline structure of the polyurethanes and to elucidate the unique mechanism for shape memory properties. The polyurethane with optimized PLLA crystalline segments showed a diamond-shape two-dimensional SAXS pattern after being stretched, which gave rise to better shape fixing and shape recovery. The shape memory behavior was further tested in 37 °C water. The biodegradable polyurethane comprising 38 wt % PCL segments and 25 wt % PLLA segments and synthesized at a relatively lower temperature by the waterborne procedure showed ∼100% shape recovery in 37 °C water. The biodegradable polyurethane SME also demonstrated good endothelial cell viability as well as low platelet adhesion/activation. We conclude that the waterborne biodegradable polyurethane SME possesses a unique thermally induced shape memory mechanism and may have potential applications in making shape memory biodegradable stents or scaffolds
Emile Franta - One of the best experts on this subject based on the ideXlab platform.
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Cationic polymerization of 1,2-epoxy-3-nitropropane in the presence of ethylene glycol, 1 : Lower Oligodiols obtained according to the activated monomer mechanism
Die Makromolekulare Chemie, 1992Co-Authors: Florence Lagarde, Léonard Reibel, Emile FrantaAbstract:The early stage of cationic polymerization of 1,2-epoxy-3-nitropropane in the presence of ethylene glycol and borontrifluoride etherate is examined. It is shown that the reaction proceeds according to the Activated Monomer Mechanism: initiation and propagation involve the nucleophilic attack of an hydroxyl end-group moiety onto a protonated monomer molecule; this attack takes place on the carbon atom located in the β-position with regard to the -CH 2 NO 2 group
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Cationic polymerization of 1,2‐epoxy‐3‐nitropropane in the presence of ethylene glycol, 2 Higher Oligodiols: Discrepancies with the activated monomer mechanism
Die Makromolekulare Chemie, 1992Co-Authors: Florence Lagarde, Léonard Reibel, Emile FrantaAbstract:The cationic polymerization of 1,2-epoxy-3-nitropropane (ENP) in the presence of ethylene glycol and boron trifluoride etherate is studied. The reaction was performed by adding the monomer stepwise in the reaction medium, so that the instantaneous mole ratio [ENP]/[OH] was below one, in order to favor the Activated Monomer Mechanism (AMM). We have shown previously that polymerization proceeds via AMM during the first two steps of the reaction (Mn < 350). In this paper, we present our results concerning the subsequent stages. In addition to the expected molecules containing one ethylene glycol unit per chain we find also some α,ω-ENP Oligodiols which do not contain any ethylene glycol unit , some mono- or diethoxylated oligomers and and some cyclics. The experimental hydroxyl concentration exceeds that introduced through the ethylene glycol used. Primary OH groups are present and the average molecular weight is limited to 500. The viscosity of the reaction medium decreases significantly when the polymerization is terminated, or simply when the medium is put in contact with atmospheric water.
