Comparison of memory effects in multiblock copolymers and covalently crosslinked multiphase polymer networks composed of the same types of oligoester segments and urethane linker

2013 ◽  
Vol 1569 ◽  
pp. 123-128
Author(s):  
Li Wang ◽  
Ulrich Nöchel ◽  
Marc Behl ◽  
Karl Kratz ◽  
Andreas Lendlein
Keyword(s):  
Shape Recovery ◽  
Polymer Networks ◽  
Memory Effects ◽  
Hexamethylene Diisocyanate ◽  
Multiblock Copolymers ◽  
Polymer Systems ◽  
Degradable Polymer ◽  
Temperature Memory Effect ◽  
Switching Temperature ◽  
Shape Fixity

ABSTRACTPhase-segregated multiblock copolymers (MBC) as well as covalently crosslinked multiphase polymer networks, which are composed of crystallizable oligo(ε-caprolactone) (OCL) and oligo(ω-pentadecalactone) (OPDL) segments have been recently introduced as degradable polymer systems exhibiting various memory effects. Both types of copolyesterurethane networks can be synthesized via co-condensation of the respective hydroxytelechelic oligomers and 2,2(4),4-trimethyl-hexamethylene diisocyanate (TMDI) as aliphatic linker.In this work the dual-shape properties as well as the temperature-memory capability of thermoplastics and covalently crosslinked copolyesterurethanes containing OCL and OPDL domains are explored. Both copolyesterurethane networks exhibited excellent dual-shape properties with high shape fixity ratios Rf ≥ 93% and shape recovery ratios in the range of 92% to 100% determined in the 2nd and 3rd test cycle, whereby the dual-shape performance was substantially improved when covalent crosslinks are present in the copolymer.A pronounced temperature-memory effect was achieved for thermoplastic as well as crosslinked copolyesterurethanes. Hereby, the switching temperature Tsw could be adjusted via the variation of the applied deformation temperature Tdeform in the range from 32 °C to 53 °C for MBC and in the range from 29 °C to 78 °C for multiphase polymer networks.

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

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.

High-strain slide-ring shape-memory polycaprolactone-based polyurethane

Soft Matter ◽  
2018 ◽  
Vol 14 (22) ◽  
pp. 4558-4568 ◽  
Author(s):  
Ruiqing Wu ◽  
Jingjuan Lai ◽  
Yi Pan ◽  
Zhaohui Zheng ◽  
Xiaobin Ding
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
High Strain ◽  
Shape Memory Polymer ◽  
Polymer Networks ◽  
Ring Structure ◽  
Recovery Ratio ◽  
Ring Shape ◽  
High Deformability ◽  
Shape Fixity

To enable shape-memory polymer networks to achieve recoverable high deformability with a simultaneous high shape-fixity ratio and shape-recovery ratio, novel semi-crystalline slide-ring shape-memory polycaprolactone-based polyurethane (SR-SMPCLU) with movable net-points constructed by a topologically interlocked slide-ring structure was designed and fabricated.

scholarly journals Thermally-Induced Shape-Memory Behavior of Degradable Gelatin-Based Networks

2021 ◽  
Vol 22 (11) ◽  
pp. 5892
Author(s):  
Axel T. Neffe ◽  
Candy Löwenberg ◽  
Konstanze K. Julich-Gruner ◽  
Marc Behl ◽  
Andreas Lendlein
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Shape Recovery ◽  
Polymer Networks ◽  
Water Soluble ◽  
Compression Tests ◽  
Thermally Induced ◽  
Thermomechanical Process ◽  
Triple Helices

Shape-memory hydrogels (SMH) are multifunctional, actively-moving polymers of interest in biomedicine. In loosely crosslinked polymer networks, gelatin chains may form triple helices, which can act as temporary net points in SMH, depending on the presence of salts. Here, we show programming and initiation of the shape-memory effect of such networks based on a thermomechanical process compatible with the physiological environment. The SMH were synthesized by reaction of glycidylmethacrylated gelatin with oligo(ethylene glycol) (OEG) α,ω-dithiols of varying crosslinker length and amount. Triple helicalization of gelatin chains is shown directly by wide-angle X-ray scattering and indirectly via the mechanical behavior at different temperatures. The ability to form triple helices increased with the molar mass of the crosslinker. Hydrogels had storage moduli of 0.27–23 kPa and Young’s moduli of 215–360 kPa at 4 °C. The hydrogels were hydrolytically degradable, with full degradation to water-soluble products within one week at 37 °C and pH = 7.4. A thermally-induced shape-memory effect is demonstrated in bending as well as in compression tests, in which shape recovery with excellent shape-recovery rates Rr close to 100% were observed. In the future, the material presented here could be applied, e.g., as self-anchoring devices mechanically resembling the extracellular matrix.

Novel Degradable Polymer Networks Containing Acetal Components and Well-Defined Backbones

2010 ◽  
Vol 63 (10) ◽  
pp. 1497 ◽  
Author(s):  
Xin-Ce Sui ◽  
Yan Shi ◽  
Zhi-Feng Fu
Keyword(s):  
Addition Reaction ◽  
Polymer Networks ◽  
Strong Acid ◽  
Hydroxyl Group ◽  
Molar Ratio ◽  
Degradable Polymer ◽  
Reversible Addition ◽  
Raft Agent ◽  
Chain Transfer Polymerization ◽  
Copolymer Network

A novel copolymer network was successfully prepared by combining the reversible addition–fragmentation chain-transfer polymerization (RAFT) and addition reaction between hydroxyl and vinyloxy groups. 2-Hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) were copolymerized in 1,4-dioxane with 2,2′-azobisisobutyronitrile as initiator and 2-(ethoxycarbonyl)prop-2-yl dithiobenzoate as a RAFT agent. The molecular weight of poly(HEMA-co-MMA) was well controlled and the polydispersity was low. The hydroxyl group from the HEMA unit in the copolymer underwent an addition reaction with 1,4-cyclohexanedimethanol divinyl ether in the presence of pyridinium p-toluenesulfonate, generating a copolymer network with an acetal component in the crosslinking segment. The crosslinking time depended on the molar ratio of HEMA and MMA in the poly(HEMA-co-MMA). After being treated in strong acid, the copolymer network was able to be degraded owing to the acetal structure, but the backbone chains of poly(HEMA-co-MMA) remained intact.

Characristics of Shape Memory Composites Combined with Shape Memory Alloy and Shape Memory Polymer

2013 ◽  
Vol 705 ◽  
pp. 169-172
Author(s):  
Xue Feng ◽  
Li Min Zhao ◽  
Xu Jun Mi
Keyword(s):  
Shape Memory ◽  
Room Temperature ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Young Modulus ◽  
Thermomechanical Properties ◽  
The Matrix ◽  
Shape Memory Composites ◽  
Shape Fixity

In order to develop high functionality of shape memory materials, the shape memory composites combined with TiNi wire and shape memory epoxy were prepared, and the mechanical and thermomechanical properties were studied. The results showed the addition of TiNi wire increased the Young modulus and breaking strength both at room temperature and at elevated temperature. The composites maintained the rates of shape fixity and shape recovery close to 100%. The maximum recovery stress increased with increasing TiNi wire volume fraction, and obtained almost 3 times of the matrix by adding 1vol% TiNi wire.

Synthesis and Characterization of Thermally Degradable Polymer Networks

1998 ◽  
Vol 10 (12) ◽  
pp. 3833-3838 ◽  
Author(s):  
Kenji Ogino ◽  
Jir-Shyr Chen ◽  
Christopher K. Ober
Keyword(s):  
Polymer Networks ◽  
Synthesis And Characterization ◽  
Degradable Polymer

Ability to Control the Glass Transition Temperature of Amorphous Shape-Memory Polyesterurethane Networks by Varying Prepolymers in Molecular Mass as well as in Type and Content of Incorporated Comonomers

2009 ◽  
Vol 1190 ◽  
Author(s):  
Joerg Zotzmann ◽  
Steffen Kelch ◽  
Armin Alteheld ◽  
Marc Behl ◽  
Andreas Lendlein
Keyword(s):  
Glass Transition ◽  
Minimally Invasive Surgery ◽  
Shape Memory ◽  
Molecular Mass ◽  
Amorphous Polymer ◽  
Polymer Networks ◽  
Precise Control ◽  
Low Weight ◽  
Switching Temperature ◽  
Selection Of

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.

Depolymerizable, adaptive supramolecular polymer nanoparticles and networks

2014 ◽  
Vol 5 (12) ◽  
pp. 3788-3794 ◽  
Author(s):  
Joshua A. Kaitz ◽  
Catherine M. Possanza ◽  
Yang Song ◽  
Charles E. Diesendruck ◽  
A. Jolanda H. Spiering ◽  
...  
Keyword(s):  
Polymeric Nanoparticles ◽  
Polymer Networks ◽  
Polymer Nanoparticles ◽  
Cross Linking ◽  
Supramolecular Polymer ◽  
Single Chain ◽  
Degradable Polymer

Depolymerizable polymers are appended with supramolecular cross-linking motifs to enable preparation of tunable single-chain polymeric nanoparticles and degradable polymer networks.

scholarly journals Determination of Shape Fixity and Shape Recovery Rate of Carbon Nanotube-filled Shape Memory Polymer Nanocomposites

2012 ◽  
Vol 41 ◽  
pp. 1641-1646 ◽  
Author(s):  
Shahrul Azam Abdullah ◽  
Aidah Jumahat ◽  
Nik Rosli Abdullah ◽  
Lars Frormann
Keyword(s):  
Carbon Nanotube ◽  
Shape Memory ◽  
Polymer Nanocomposites ◽  
Recovery Rate ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Shape Fixity
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