Rewritable Shape-Memory Polylactic Acid Fabricated by Thermo-Reversible Cross-Linking Based on the Diels-Alder Reaction

Inoue, Kentaro; Yamashiro, Midori; Iji, Masatoshi

doi:10.1295/koron.62.261

Cited by 9 publications

(12 citation statements)

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“…The related chain-extension based on Diels-Alder reaction had ever been reported by Yoshie et al, who used maleimide linkers for chain coupling of bis furan-terminated polyesters [22,23]. Inoue et al also exhibited the Diels-Alder coupling of bis furanterminated PLLA with maleimide linkers [24,25]. These examples indicate that the terminal Diels-Alder reaction between furan-and maleimide-terminated prepolymers can be a good method for coupling polymer chains having different structure and properties.…”

Section: Introductionmentioning

confidence: 80%

Reactive Electrospinning of Stereoblock Polylactides Prepared via Spontaneous Diels-Alder Coupling of Bis Maleimide-terminated Poly-L-lactide and Bis Furan-terminated Poly-D-lactide

et al. 2012

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Bis maleimide-terminated poly-L-lactide (M-PLLA-M) and bis furan-terminated poly-D-lactide (F-PDLA-F) were synthesized by isocyanate coupling reactions of mono maleimide-terminated PLLA (M-PLLA) and mono furanterminated PDLA (F-PDLA) that had been prepared by the ordinary ring opening polymerization of L-and D-lactides with N-(2-hydroxyethyl)-maleimide and furfurylamine as the initiators, respectively. Both the M-PLLA-M and F-PDLA-F were dissolved in CH2Cl2 in 1 : 1 ratio and subjected to the ordinary electrospinning where the initial polymer concentration was increased up to 20 wt% because of the prepolymer state of the solute and the fiber diameter could be retained in nanometer to submicron size. The molecular weight of the polymers was found to have increased from 1.0 × 10 4 to 2.5 and 4.5 × 10 4 after the electrospinning and post annealing, respectively, due to the spontaneous chain extension taking place by the terminal Diels-Alder reaction of M-PLLA-M and F-PDLA-F to form a stereoblock polylactide. The as-spun fibers were amorphous or partially semi-crystalline, whereas the annealed fibers become fully crystalline due to the formation of the stereocomplex showing a melting temperature above 200°C.

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Section: Introductionmentioning

confidence: 80%

Reactive Electrospinning of Stereoblock Polylactides Prepared via Spontaneous Diels-Alder Coupling of Bis Maleimide-terminated Poly-L-lactide and Bis Furan-terminated Poly-D-lactide

et al. 2012

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“…The maleimide linkers were as previously described. [3][4][5]14 Materials PLA was purchased from Unitika Ltd., 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (WSC) was purchased from Wako Pure Chemical Industries, and other reagents were purchased from Kanto Chemical. All the reagents and solvents were used as received.…”

Section: Methodsmentioning

confidence: 99%

“…For the first condition, the reaction temperature was set to 100 C, hence the Diels-Alder reaction between furan and maleimide functions was monitored around 100 C in our DSC study. [3][4][5] In the case of the first condition (Condition I: 100 C for 1 h), which produced a low reaction ratio between furan and maleimide functions, the flexural strengths of the TCPs cross-linked with DDM (TCPd-I), HDM (TCPh-I), and TMI (TCPt-I) were lower than that of neat PLA (120 MPa). We suggested that the insufficient flexural strengths were caused by defects in the cross-linked structures because of the low reaction ratios.…”

Section: Diels-alder Reaction Between Fp and Maleimide Linkermentioning

confidence: 99%

“…It actually showed shape-memory behavior as good as that of a reference PLA cross-linked with rigid TMI. [3][4][5] The original shape (a) was easily deformed into a C-shape (b) by heating the plate at 70…”

Section: Shape-memory and Recycle Behavior Of Tcpmentioning

confidence: 99%

“…Therefore, we developed new intelligent PLA compounds that perform recyclable shape-memory by cross-linking PLA based on thermo-reversible Diels-Alder cyclo-addition. [3][4][5] Our PLA compounds have the potential to expand the use of biomassbased polymers in future high-performance products, for example, biomedical devices and wearable electronic equipments, the shapes of which users can reform easily.…”

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confidence: 99%

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Recyclable Shape-memory and Mechanical Strength of Poly(lactic acid) Compounds Cross-linked by Thermo-reversible Diels-Alder Reaction

Yamashiro

Inoue

Iji

2008

Polym J

Self Cite

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We developed poly(lactic acid) (PLA) compounds which achieved recyclable shape-memory and practical strength. The PLA compounds were composed of a furan-modified poly(lactic acid) and a maleimide linker, and cross-linked by the Diels-Alder cyclo-addition between furan and maleimide functions. The cross-linking condition was optimized to increase a reaction ratio between furan and maleimide functions, and the increase in the reaction ratio decreased the defects in its structure and enhanced its strength. Furthermore, using a maleimide linker with a flexible unit (dodecamethylene dimaleimide) induced relaxation of the inner strain in the PLA compound also enhanced its strength.KEY WORDS: Poly(lactic acid) / Shape-memory / Thermo-reversible Cross-linking / Diels-Alder Reaction / Recycling / Biomass-based polymers made from renewable plant resources, including poly(lactic acid) (PLA), have recently received increasing attention as new environmentally friendly polymers and are now starting to be used in products. However, the applications of biomass-based polymers have been limited because many practical characteristics of biomass-based polymers are lower than those of conventional petroleumbased polymers. 1,2For biomass-based polymers to be used in a larger variety of products, the characteristics of such polymers should be superior to those of petroleum-based polymers. Therefore, we developed new intelligent PLA compounds that perform recyclable shape-memory by cross-linking PLA based on thermo-reversible Diels-Alder cyclo-addition.3-5 Our PLA compounds have the potential to expand the use of biomassbased polymers in future high-performance products, for example, biomedical devices and wearable electronic equipments, the shapes of which users can reform easily.Generally, shape-memory polymers have cross-linked structures, which can have either intermolecular bonding or covalent bonding to determine their permanent shapes. 6,7 Shape-memory polymers cross-linked by intermolecular bonding, for example, entanglement networks, crystal domains, and hydrogen bonding can be remolded into other shapes by melting them at temperatures above their melting points, however their shape-memory performance is insufficient because of creep behavior due to weak intermolecular bonding. Shape-memory polymers cross-linked by covalent bonding cannot be melted due to covalently cross-linked structures and then they are hard to be recycled into other products, although these shape-memory polymers have sufficient shape-memory because their creep behavior is retarded by strong covalent bonding. Therefore, conventional shape-memory polymers hardly perform as recyclable shape-memory.In our previous work, we achieved recyclable shapememory by using thermo-reversible bonding, which is based on a Diels-Alder reaction, to cross-link PLA as a biomassbased polymer. Some kinds of Diels-Alder reactions are well known as thermo-reversible reactions [8][9][10][11][12][13] and they are suitable to be introduced into PLA because the reactions occur betwee...

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A review of shape memory polymers bearing reversible binding groups

Lewis

Dell

2016

J Polym Sci B Polym Phys

141

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Shape memory polymers (SMP) can be deformed to a stable, temporary shape and recovered to their original shape by applying a stimulus. These networks rely on the presence of two types of net points to establish their permanent and temporary shapes. Classical strategies to stabilize temporary shapes rely on cooling below T g /T m where macromolecules become pinned in a stressed state. Recovery of the SMP usually involves heating to above the transition temperature where the permanent shape is remembered. Employing reversible binding groups (RBGs) in SMPs has emerged as an alternative strategy for stabilizing temporary shapes or imparting recyclability of the permanent shape. The use of dynamic chemistry often engenders additional functionality such as intrinsic self-healing characteristics or alternative shape recovery triggering strategies. SMPs bearing both supramolecular and covalent RBGs will be reviewed with an emphasis on hydrogen bonding, ionic interactions, metal-ligand coordination, and dynamic covalent exchange and addition reactions.

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Rewritable Shape-Memory Polylactic Acid Fabricated by Thermo-Reversible Cross-Linking Based on the Diels-Alder Reaction

Abstract: Scheme 2. Synthesis of the reversible cross-linked PLA (RCP).

Cited by 9 publications

References 0 publications

Reactive Electrospinning of Stereoblock Polylactides Prepared via Spontaneous Diels-Alder Coupling of Bis Maleimide-terminated Poly-L-lactide and Bis Furan-terminated Poly-D-lactide

Reactive Electrospinning of Stereoblock Polylactides Prepared via Spontaneous Diels-Alder Coupling of Bis Maleimide-terminated Poly-L-lactide and Bis Furan-terminated Poly-D-lactide

Recyclable Shape-memory and Mechanical Strength of Poly(lactic acid) Compounds Cross-linked by Thermo-reversible Diels-Alder Reaction

A review of shape memory polymers bearing reversible binding groups

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