Toughening-modified epoxy-amine system: Cure kinetics, mechanical behavior, and shape memory performances

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Original post:
http://onlinelibrary.wiley.com/doi/10.1002/app.40853/abstract

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Toughening-modified epoxy-amine system: Cure kinetics, mechanical behavior, and shape memory performances

1. Xianghai Jing¹, 
 
2. Yuyan Liu^1,*, 
 
3. Yuxi Liu¹, 
 
4. Zhenguo Liu¹ and
 
5. Huifeng Tan^2,*

Article first published online: 30 APR 2014

DOI: 10.1002/app.40853

Copyright © 2014 Wiley Periodicals, Inc.

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Journal of Applied Polymer Science

Early View (Online Version of Record published before inclusion in an issue)

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Keywords:

• differential scanning calorimetry;
 
• kinetics;
 
• resins;
 
• shape memory;
 
• toughness

ABSTRACT

Shape memory epoxy resins are derived on reacting E51 with triethylenetetramine in presence of the toughening agent polypropylene glycol diglycidyl ether (PPGDGE). The curing behaviors are studied with differential scanning calorimetry. The toughening system shows a decrease in activation energy. Šesták–Berggren model is utilized to establish the kinetic equations. The fitting results prove that the equations can well describe the reactions. Tensile tests and dynamic mechanical analysis are used to analyze mechanical performances and thermodynamics. Shape memory properties are characterized by fold-deploy tests. The elongation at break increases as the concentration of PPGDGE increases. The toughening materials have lower glass transition temperature (T_g). The fixable ratios of all systems are greater than 99.5%. The shape recovery time decreases with increasing the PPGDGE concentration. The optimal system can fully recover its original shape in about 2 min at T_g + 30°C, and exhibit the maximum fold-deploy cycles as 13 cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40853.

For related shape memory application resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

Highly pH-Sensitive Polyurethane Designed for Switching both Shape Memory and Drug Release

Here is the latest from:

Polymer Chemistry

Encompassing all aspects of synthetic and biological macromolecules, and related emerging areas

Original post:
http://pubs.rsc.org/en/content/articlelanding/2014/py/c4py00474d#!divAbstract

Related resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

Paper

Highly pH-Sensitive Polyurethane Designed for Switching both Shape Memory and Drug Release

shaobing Zhou,   Hongmei Chen,   Ying Li,   Y Liu,  Tao Gong and   Lin Wang  

Polym. Chem., 2014, Accepted Manuscript

DOI: 10.1039/C4PY00474D
Received 03 Apr 2014, Accepted 01 May 2014
First published online 02 May 2014

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In this study, a highly pH-sensitive polymer is synthesised by introducing pyridine rings into the backbone of polyurethane. The chemical structure of the resulting materials is confirmed by FT-IR and 1H-NMR. To analyse the mechanism of the pH sensitivity of this polymer, its structural transformations under acidic and basic conditions are studied by FT-IR, theoretical calculation and 1H-NMR. We observe that the mechanism of pH responsiveness is the formation of a hydrogen bond interaction between the N atom of the pyridine ring and the H-N of urethane in neutral or alkaline environments which is disrupted under acidic conditions due to the protonation of the pyridine ring. The pH-sensitivity is demonstrated by simply adjusting the pH value of the environment, which can act as a switch to control shape memory and drug release. Unlike other systems with thermally sensitive behaviour, the shape memory functionality of this material is independent of temperature, which is dependent only on the variation in the pH of the environment. This strategy provides a potent tool for the design of multifunctional materials based on the physiological environment to fulfil the complex requirements of drug delivery and tissue engineering systems.

For related shape memory application resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

SMA: BME Announces Expanded Availability Of The Speed Shift™ Nitinol Compression Fixation System Designed For Sliding Calcaneal Osteotomies

Here is the latest from: Digital Journal on Nitinol and bone fixation

Original post:
http://www.digitaljournal.com/pr/1876762

For related shape memory application resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

PR Newswire

SAN ANTONIO, April 28, 2014

SAN ANTONIO, April 28, 2014 /PRNewswire/ -- BioMedical Enterprises, Inc. (BME), a pioneer and U.S. leader in shape memory technology for small bone fixation, announced today the nationwide availablity of the Speed Shift™ Continuous Active Compression System.

The Speed Shift™ Continuous Active Compression implant is the world's first superelastic Nitinol bone fixation device with an offset bridge to accommodate uneven bone surfaces that are procedure-specific, such as for sliding calcaneal osteotomies. This unique superelastic implant, with a stepped bridge (available in a range of sizes from 4mm to 12mm) offers the Foot & Ankle surgeon intraoperative options for reconstruction of flatfoot and high arch conditions.  In addition, the new Speed Shift System is a patented, fully disposable, pre-sterilized implant & instrumentation system designed to enhance operating room efficiencies.

"BME is aggresively driving innovation in the area of Nitinol Shape Memory systems for small bone fixation," states Keith M. Peeples, President & CEO of BME. "We saw great success with the game-changing technologies behind the Speed™ Continuous Active Compression System. The Speed Shift™ builds upon that foundation and give surgeons more anatomically-shaped implant options. Our mission is to design and manufacture implants that significantly enhance the healing of bone without compromise."

BME, Inc. is the only U.S. manufacturer of Nitinol metal implants for musculoskeletal fixation. BME has led the innovation and advancement of Nitinol implants and patented disposable instrumentation in the U.S. market. BME continues to develop new standards for manufacturing processes while defining new parameters for product development with emphasis on education of our surgeon communities on the benefits of BME shape memory technologies.

SOURCE BME, Inc.

Read more: http://www.digitaljournal.com/pr/1876762#ixzz31HpQZUp2

Related resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

Here is the latest from: ESRF, The European Synchrotron

Original post:
http://www.esrf.eu/home/events/Seminars/area-seminars/esrf-seminars-list/toward-a-better-understanding-of-shape-memory-alloys.html

For related shape memory application resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

Toward a better understanding of Shape Memory Alloys

Seminar

Since its discovery in the early 1960s, near equiatomic Ni-Ti alloy has attracted a lot of attention due to its unique functional properties (superelasticity, one-way and two-way shape memory) and its excellent mechanical properties (low elastic anisotropy, high resistance to corrosion and abrasion, …). Its crystallographic structure can change from the cubic austenite to the monoclinic martensite through the application of temperature or strain. It is from this reversible phase transformation that the unique functional properties of NiTi originate.

Ni-Ti alloys are mainly produced in the form of thin wires in a cold-worked state, which do not show any specific properties. To achieve the functional properties, a heat treatment, which traditionally can take up to 1 hour in a furnace, is needed. Recently, a non conventional technique called Final Thermo-Mechanical Treatment by Electric Current (FTMT-EC) has been developed, enabling a reduction in the time needed to heat treat a wire down to a few milliseconds.

In this talk, I will present new results related to the influence of this new heat treatment on the evolution of the microstructure and to properties of the wires which have been subjected to this new technique. These results are based on data obtained from experiments performed at the ESRF, on the Material Science Beamline ID11 and the High Resolution Powder Diffraction Beamline ID31.

Visitors from off-site please contact Claudine Roméro tel +33 (0)4 76 88 20 27 to arrange for a gate pass.

Requests made by e-mail will be confirmed. If you do not receive a confirmation e-mail, please contact us by phone.

Related resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

Here is the latest from:

Original post:
http://pubs.acs.org/doi/pdfplus/10.1021/jp500709m

For related shape memory application resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

High-Speed Actuation and Mechanical Properties of Graphene-Incorporated Shape Memory Polyurethane Nanofibers

Hye Jon Yoo, Sibdas Singha Mahapatra, and Jae Whan Cho *

Department of Organic and Nano System Engineering,Konkuk University, Seoul 143-701, Republic of Korea

J. Phys. Chem. C, Article ASAP

DOI: 10.1021/jp500709m

Publication Date (Web): April 28, 2014

Copyright © 2014 American Chemical Society

*E-mail: jwcho@konkuk.ac.kr. Phone: +82 (2) 4503513. Fax: +82 (2) 4578895.

Related resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

Here is the latest from the Journal Applied Polymer Science on Shape Memory performance

Original post:
http://onlinelibrary.wiley.com/doi/10.1002/app.40853/abstract

For related shape memory application resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

Toughening-modified epoxy-amine system: Cure kinetics, mechanical behavior, and shape memory performances

1. Xianghai Jing¹, 
2. Yuyan Liu^1,*, 
3. Yuxi Liu¹, 
4. Zhenguo Liu¹ and
5. Huifeng Tan^2,*

Article first published online: 30 APR 2014

DOI: 10.1002/app.40853

Copyright © 2014 Wiley Periodicals, Inc.

Issue

Journal of Applied Polymer Science

Early View (Online Version of Record published before inclusion in an issue)

ABSTRACT

Shape memory epoxy resins are derived on reacting E51 with triethylenetetramine in presence of the toughening agent polypropylene glycol diglycidyl ether (PPGDGE). The curing behaviors are studied with differential scanning calorimetry. The toughening system shows a decrease in activation energy. Šesták–Berggren model is utilized to establish the kinetic equations. The fitting results prove that the equations can well describe the reactions. Tensile tests and dynamic mechanical analysis are used to analyze mechanical performances and thermodynamics. Shape memory properties are characterized by fold-deploy tests. The elongation at break increases as the concentration of PPGDGE increases. The toughening materials have lower glass transition temperature (T_g). The fixable ratios of all systems are greater than 99.5%. The shape recovery time decreases with increasing the PPGDGE concentration. The optimal system can fully recover its original shape in about 2 min at T_g + 30°C, and exhibit the maximum fold-deploy cycles as 13 cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40853.

Related resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

Highly pH-Sensitive Polyurethane Designed for Switching both Shape Memory and Drug Release

Here is the latest on Shape Memory and Drug Release:

Polymer Chemistry

Encompassing all aspects of synthetic and biological macromolecules, and related emerging areas

Original post:
http://pubs.rsc.org/en/content/articlelanding/2014/py/c4py00474d#!divRelatedContent

For related shape memory application resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/

Abstract

In this study, a highly pH-sensitive polymer is synthesised by introducing pyridine rings into the backbone of polyurethane. The chemical structure of the resulting materials is confirmed by FT-IR and 1H-NMR. To analyse the mechanism of the pH sensitivity of this polymer, its structural transformations under acidic and basic conditions are studied by FT-IR, theoretical calculation and 1H-NMR. We observe that the mechanism of pH responsiveness is the formation of a hydrogen bond interaction between the N atom of the pyridine ring and the H-N of urethane in neutral or alkaline environments which is disrupted under acidic conditions due to the protonation of the pyridine ring. The pH-sensitivity is demonstrated by simply adjusting the pH value of the environment, which can act as a switch to control shape memory and drug release. Unlike other systems with thermally sensitive behaviour, the shape memory functionality of this material is independent of temperature, which is dependent only on the variation in the pH of the environment. This strategy provides a potent tool for the design of multifunctional materials based on the physiological environment to fulfil the complex requirements of drug delivery and tissue engineering systems.

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For related resources, Design for Disassembly, Eco-Design, Environment and AD Technology guidelines related to this can be downloaded for free at:

http://www.activedisassembly.com/strategy/