Controlling the Switching Temperature of Biodegradable, Amorphous, Shape-Memory Poly(rac-lactide)urethane Networks by Incorporation of Different Comonomers

AbstractThe need of intelligent implant materials for applications in the area of minimally invasive surgery leads to tremendous attention for polymers which combine degradability and shape-memory capability. Application of heat, and thereby exceeding a certain switching temperature Tsw, causes the device to changes its shape. The precise control of Tsw is particularly challenging. It was investigated in how far Tg, that can be used as Tsw, of amorphous polymer networks from star-shaped polyester macrotetrols crosslinked with a low-weight linker can be controlled systematically by incorporation of different comonomers into poly(rac-lactide) prepolymers. The molecular mass of the prepolymers as well as type and content of the comonomers was varied. The Tg could be adjusted by selection of comonomer type and ratio without affecting the advantageous elastic properties of the polymer networks.

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HEAT-TRIGGERED SHAPE MEMORY EFFECT OF PEROXIDE CROSS-LINKED ETHYLENE–METHACRYLIC ACID COPOLYMER/NITRILE–BUTADIENE RUBBER THERMOPLASTIC VULCANIZATES WITH SEA-ISLAND STRUCTURE

Rubber Chemistry and Technology ◽

10.5254/rct.21.79926 ◽

2021 ◽

Author(s):

Yingtao Sun ◽

Jiahao Li ◽

Kerui Liao ◽

Jing Hua ◽

Zhaobo Wang

Keyword(s):

Shape Memory ◽

Methacrylic Acid ◽

Shape Recovery ◽

Butadiene Rubber ◽

X Ray Diffraction ◽

Nitrile Butadiene Rubber ◽

Acid Copolymer ◽

Thermoplastic Vulcanizates ◽

Switching Temperature ◽

Shape Fixity

ABSTRACT Designing shape memory polymers (SMPs) based on thermoplastic vulcanizates (TPVs) is an essential research topic. An efficient SMP is designed with typical sea-island structured ethylene–methacrylic acid copolymer/nitrile–butadiene rubber (EMA/NBR) TPVs in which the heat-control switched phase performed by the EMA phase is related to the shape fixity ability. The results show that the heat-triggered SMPs exhibit surprising shape memory properties (shape fixity >95%, shape recovery >95%, and fast recovery speed <30 s at the switching temperature of 95 °C). Through X-ray diffraction characterization, it is seen that the shape fixity of TPVs is achieved mainly through ethylene crystallization. The switching temperature is largely determined by the melting temperature (98 °C) obtained by differential scanning calorimetery.

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Novel synthetic strategy toward shape memory polyurethanes with a well-defined switching temperature

Polymer ◽

10.1016/j.polymer.2009.07.021 ◽

2009 ◽

Vol 50 (19) ◽

pp. 4447-4454 ◽

Cited By ~ 53

Author(s):

S. D'hollander ◽

G. Van Assche ◽

B. Van Mele ◽

F. Du Prez

Keyword(s):

Shape Memory ◽

Synthetic Strategy ◽

Switching Temperature

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Controlling the switching temperature of biodegradable shape memory polymers composed of stereocomplex polylactide / poly(,-lactide-co-ε-caprolactone) blends

Polymer ◽

10.1016/j.polymer.2021.124190 ◽

2021 ◽

Vol 233 ◽

pp. 124190

Author(s):

Kenta Hashimoto ◽

Naruki Kurokawa ◽

Atsushi Hotta

Keyword(s):

Shape Memory ◽

Shape Memory Polymers ◽

Switching Temperature

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Biocompatible shape‐memory poly(vinyl chloride) with a tunable switching temperature via a plasticization effect

Journal of Applied Polymer Science ◽

10.1002/app.47992 ◽

2019 ◽

Vol 136 (39) ◽

pp. 47992 ◽

Cited By ~ 1

Author(s):

Yu Zheng ◽

Min Yin ◽

Xue Yang ◽

Ying Li ◽

Jiabin Shen ◽

...

Keyword(s):

Shape Memory ◽

Vinyl Chloride ◽

Plasticization Effect ◽

Poly Vinyl Chloride ◽

Switching Temperature

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Biobased Poly(propylene sebacate) as Shape Memory Polymer with Tunable Switching Temperature for Potential Biomedical Applications

Biomacromolecules ◽

10.1021/bm2000378 ◽

2011 ◽

Vol 12 (4) ◽

pp. 1312-1321 ◽

Cited By ~ 127

Author(s):

Baochun Guo ◽

Yongwen Chen ◽

Yanda Lei ◽

Liqun Zhang ◽

Wen You Zhou ◽

...

Keyword(s):

Shape Memory ◽

Biomedical Applications ◽

Shape Memory Polymer ◽

Poly Propylene ◽

Switching Temperature

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Mechanical Properties of Polymer Blends Having Shape-memory Capability

MRS Proceedings ◽

10.1557/proc-1190-nn01-05 ◽

2009 ◽

Vol 1190 ◽

Cited By ~ 4

Author(s):

Marc Behl ◽

Ute Ridder ◽

Wolfgang Wagermaier ◽

Steffen Kelch ◽

Andreas Lendlein

Keyword(s):

Mechanical Properties ◽

Polymer Blends ◽

Shape Memory ◽

Design Principle ◽

Shape Memory Polymers ◽

Multiblock Copolymers ◽

New Class ◽

Binary Polymer ◽

Permanent Shape ◽

Switching Temperature

AbstractThe general design principle of shape-memory polymers (SMP) requires two key compo-nents: covalent or physical crosslinks (hard domains) determining the permanent shape and switching domains fixing the temporary shape as well as influencing the switching temperature Tsw. In conventional thermoplastic SMP hard and switching domains determining segments are combined in one macromolecule, e.g. block copolymers such as polyurethanes. Recently, binary polymer blends having shape-memory properties, from two different multiblock copolymers have been presented, whereby the first one is providing the segments forming hard domains and the second one the segments forming the switching domains. Besides the shape-memory proper-ties, the mechanical properties of such materials are application relevant. Here we investigate how the blend composition influences mechanical properties of this new class of shape-memory materials.

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Tensile Failure of 55-Nitinol Wire

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113858 ◽

1975 ◽

Vol 33 ◽

pp. 46-47

Author(s):

F. I. Grace

Keyword(s):

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Stoichiometric Composition ◽

Tensile Failure ◽

Initial State ◽

Initial Shape ◽

Nitinol Wire ◽

Cscl Type ◽

Shear Transformation

An interest in NiTi alloys with near stoichiometric composition (55 NiTi) has intensified since they were found to exhibit a unique mechanical shape memory effect at the Naval Ordnance Laboratory some twelve years ago (thus refered to as NITINOL alloys). Since then, the microstructural mechanisms associated with the shape memory effect have been investigated and several interesting engineering applications have appeared.The shape memory effect implies that the alloy deformed from an initial shape will spontaneously return to that initial state upon heating. This behavior is reported to be related to a diffusionless shear transformation which takes place between similar but slightly different CsCl type structures.

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TEM study of order, structure and defects of β and martensite in Cu-Al-Mn shape memory alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100174072 ◽

1990 ◽

Vol 48 (4) ◽

pp. 188-189

Author(s):

J.M. Guilemany ◽

F. Peregrin

Keyword(s):

Shape Memory ◽

Orthophosphoric Acid ◽

Isopropyl Alcohol ◽

Metastable Phase ◽

Characteristic Temperature ◽

Ethanol Solution ◽

Order Structure ◽

Thin Foils ◽

Polycrystalline Alloys ◽

Diamond Saw

The shape memory effect (SME) shown by Cu-Al-Mn alloys stems from the thermoelastic martensitic transformation occuring between a β (L2,) metastable phase and a martensitic phase. The TEM study of both phases in single and polycrystalline Cu-Al-Mn alloys give us greater knowledge of the structure, order and defects.The alloys were obtained by vacuum melting of Cu, Al and Mn and single crystals were obtained from polycrystalline alloys using a modified Bridgman method. Four different alloys were used with (e/a) ranging from 1.41 to 1.46 . Two different heat treatments were used and the alloys also underwent thermal cycling throughout their characteristic temperature range -Ms, Mf, As, Af-. The specimens were cut using a low speed diamond saw and discs were mechanically thinned to 100 μm and then ion milled to perforation at 4 kV. Some thin foils were also prepared by twin-jet electropolishing, using a (1:10:50:50) urea: isopropyl alcohol: orthophosphoric acid: ethanol solution at 20°C. The foils were examinated on a TEM operated at 200 kV.

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