Biodegradable Shape-Memory Polymer Networks:  Characterization with Solid-State NMR

Bertmer, Marko; Adams, Alina; Blomenkamp-Höfges, Iris; Kelch, Steffen; Lendlein, Andreas

doi:10.1021/ma0501489

Cited by 57 publications

(53 citation statements)

References 23 publications

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“…It has been reported that a high glassy modulus correlates with high shape fixity during simultaneous cooling and unloading, and elasticity ratios above 100 allow for greater resistance to deformation and better shape recovery. 13 According to these findings, material with cure step 1 at 258C should exhibit less shape recovery than the others, since the elastic ratio is 53 while other elastic ratios are above 100.…”

Section: Dynamic Mechanical Analysismentioning

confidence: 95%

“…In addition, their surface can readily be modified for biocompatibility and drug elution. 12,13 Thermomechanical behavior and shape memory properties have been reported for SMP materials made from polyurethanes, 1,2,14-17 ethylene-vinyl acetate copolymers, 18 oligo(e-caprolactones), 19 poly(ethylene glycol), and poly(ethylene terephthalates). 20 The shape memory effect of thermal SMPs resides in the structure of the polymer, which is often described as being a two phase structure comprised of a hard, or fixing phase, and a soft, or reversible phase.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Shape‐memory behavior of thermally stimulated polyurethane for medical applications

Baer

Wilson

Matthews

et al. 2006

J of Applied Polymer Sci

148

108

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Shape memory polymers (SMPs) have been of great interest because of their ability to be thermally actuated to recover a predetermined shape. Medical applications in clot extracting devices and stents are especially promising. We investigated the thermomechanical properties of a series of Mitsubishi SMPs for potential application as medical devices. Glass transition temperatures and moduli were measured by differential scanning calorimetry and dynamic mechanical analysis. Tensile tests were performed with 20 and 100% maximum strains, at 37 and 808C, which are respectively, body temperature and actuation temperature. Glass transitions are in a favorable range for use in the body (35-758C), with high glassy and rubbery shear moduli in the range of 800 and 2 MPa respectively. Constrained stress-strain recovery cycles showed very low hysteresis after three cycles, which is important to know for preconditioning of the material to ensure identical properties during applications. Isothermal free recovery tests showed shape recoveries above 94% for MP5510 thermoset SMP cured at different temperatures. One material exhibited a shape fixity of 99% and a shape recovery of 85% at 808C over one thermomechanical cycle. These polyurethanes appear particularly well suited for medical applications in deployment devices such as stents or clot extractors.

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Section: Dynamic Mechanical Analysismentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Shape‐memory behavior of thermally stimulated polyurethane for medical applications

Baer

Wilson

Matthews

et al. 2006

J of Applied Polymer Sci

148

108

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show abstract

“…Crosslinking usually brings further benefits with, such as high recovery stress and rate compared to the linear counterparts. The group of Lendlein functionalized oligomers composed of L-lactide and glycolide with UV-curable methacrylate end groups [17]. The comonomer ratio and length of the chain segments in the corresponding polymer (PLLA-GA) were varied in the experiments.…”

Section: Molecular Structure 211 T G -Based Systemsmentioning

confidence: 99%

Biodegradable polyester-based shape memory polymers: Concepts of (supra)molecular architecturing

Karger‐Kocsis

Kéki

2014

Express Polym. Lett.

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Shape memory (SM) biodegradable polymers (SMPs) and related composites are emerging smart materials in different applications. SMPs may adopt one (dual-shape), two (triple-shape) or several (multishape) stable temporary shapes and recover their permanent shape (or other temporary shapes in case of multi-shape versions) upon the action of an external stimulus. The external stimulus may be temperature, pH, water, light irradiation, redox condition etc. In most cases, however, the SMPs are thermally activated. The 'switching' or transformation temperature (T trans ), enabling the material to return to its permanent shape, is either linked with the glass transition (T g ) or with the melting temperature (T m ).Thus, SMPs are often subdivided based on their switch types into T g -or T m -based SMPs. As reversible 'switches' other mechanisms such as liquid crystallization and related transitions, supermolecular assembly/disassembly, irradiation-induced reversible network formation, formation and disruption of a percolation network, may also serve [1]. The permanent shape is guaranteed by physical or chemical network structures. The latter may be both on molecular and supramolecular levels. Linkages of these networks are termed net points. The temporary shape is created by mechanical deformation above T trans . In some cases the deformation temperature may be below Abstract. Shape memory polymers (SMPs) are capable of memorizing one or more temporary shapes and recovering to the permanent shape upon an external stimulus that is usually heat. Biodegradable polymers are an emerging family within the SMPs. This minireview delivers an overlook on actual concepts of molecular and supramolecular architectures which are followed to tailor the shape memory (SM) properties of biodegradable polyesters. Because the underlying switching mechanisms of SM actions is either related to the glass transition (T g ) or melting temperatures (T m ), the related SMPs are classified as T g -or T m -activated ones. For fixing of the permanent shape various physical and chemical networks serve, which were also introduced and discussed. Beside of the structure developments in one-way, also those in two-way SM polyesters were considered. Adjustment of the switching temperature to that of the human body, acceleration of the shape recovery, enhancement of the recovery stress, controlled degradation, and recycling aspects were concluded as main targets for the future development of SM systems with biodegradable polyesters.

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“…While other classes of thermally activated shape memory materials have been developed, shape memory alloys (SMA) [2] and shape memory ceramics [3] being the two other major classes [4], SMPs have a number of unique and promising properties. Specifically, in the field of medicine, research into the development of new SMP with adjustable modulus [5], greater strain recovery, an adjustable actuation temperature, and the option of bioresorption [1,6] has opened the possibility for new medical devices and applications.…”

Section: Introductionmentioning

confidence: 99%

Inductively Heated Shape Memory Polymer for the Magnetic Actuation of Medical Devices

Buckley

McKinley

Wilson

et al. 2006

IEEE Trans. Biomed. Eng.

330

205

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Presently there is interest in making medical devices such as expandable stents and intravascular microactuators from shape memory polymer (SMP). One of the key challenges in realizing SMP medical devices is the implementation of a safe and effective method of thermally actuating various device geometries in vivo. A novel scheme of actuation by Curiethermoregulated inductive heating is presented. Prototype medical devices made from SMP loaded with Nickel Zinc ferrite ferromagnetic particles were actuated in air by applying an alternating magnetic field to induce heating. Dynamic mechanical thermal analysis was performed on both the particle-loaded and neat SMP materials to assess the impact of the ferrite particles on the mechanical properties of the samples. Calorimetry was used to quantify the rate of heat generation as a function of particle size and volumetric loading of ferrite particles in the SMP. These tests demonstrated the feasibility of SMP actuation by inductive heating. Rapid and uniform heating was achieved in complex device geometries and particle loading up to 10% volume content did not interfere with the shape recovery of the SMP.

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Biodegradable Shape-Memory Polymer Networks: Characterization with Solid-State NMR

Cited by 57 publications

References 23 publications

Shape‐memory behavior of thermally stimulated polyurethane for medical applications

Shape‐memory behavior of thermally stimulated polyurethane for medical applications

Biodegradable polyester-based shape memory polymers: Concepts of (supra)molecular architecturing

Inductively Heated Shape Memory Polymer for the Magnetic Actuation of Medical Devices

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