Triple Shape Memory Effect of Star-Shaped Polyurethane

Yang, Xifeng; Wang, Lin; Wang, Wenxi; Chen, Hongmei; Yang, Guang; Zhou, Shaobing

doi:10.1021/am5001344

Cited by 78 publications

(52 citation statements)

References 45 publications

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“…1.35−1.42 ppm, H-(e) at 4.05−4.1 ppm, all chemistry shift signals matched with the corresponding protons, indicate the successful synthesis of PCL−PEG-PCL 53. From the intensity of signal H-(a) and H-(e), the repeating unit m was calculated and then M n was deduced.…”

mentioning

confidence: 88%

pH-Responsive Shape Memory Poly(ethylene glycol)–Poly(ε-caprolactone)-based Polyurethane/Cellulose Nanocrystals Nanocomposite

Chen

Liu

et al. 2015

ACS Appl. Mater. Interfaces

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164

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In this study, we developed a pH-responsive shape-memory polymer nanocomposite by blending poly(ethylene glycol)-poly(ε-caprolactone)-based polyurethane (PECU) with functionalized cellulose nanocrystals (CNCs). CNCs were functionalized with pyridine moieties (CNC-C6H4NO2) through hydroxyl substitution of CNCs with pyridine-4-carbonyl chloride and with carboxyl groups (CNC-CO2H) via 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) mediated surface oxidation, respectively. At a high pH value, the CNC-C6H4NO2 had attractive interactions from the hydrogen bonding between pyridine groups and hydroxyl moieties; at a low pH value, the interactions reduced or disappeared due to the protonation of pyridine groups, which are a Lewis base. The CNC-CO2H responded to pH variation in an opposite manner. The hydrogen bonding interactions of both CNC-C6H4NO2 and CNC-CO2H can be readily disassociated by altering pH values, endowing the pH-responsiveness of CNCs. When these functionalized CNCs were added in PECU polymer matrix to form nanocomposite network which was confirmed with rheological measurements, the mechanical properties of PECU were not only obviously improved but also the pH-responsiveness of CNCs could be transferred to the nanocomposite network. The pH-sensitive CNC percolation network in polymer matrix served as the switch units of shape-memory polymers (SMPs). Furthermore, the modified CNC percolation network and polymer molecular chains also had strong hydrogen bonding interactions among hydroxyl, carboxyl, pyridine moieties, and isocyanate groups, which could be formed or destroyed through changing pH value. The shape memory function of the nanocomposite network was only dependent on the pH variation of the environment. Therefore, this pH-responsive shape-memory nancomposite could be potentially developed into a new smart polymer material.

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confidence: 88%

pH-Responsive Shape Memory Poly(ethylene glycol)–Poly(ε-caprolactone)-based Polyurethane/Cellulose Nanocrystals Nanocomposite

Chen

Liu

et al. 2015

ACS Appl. Mater. Interfaces

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164

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“…As a potential intelligent material, shape memory polymers (SMPs) have the capability of changing from one temporary shape to a predefined shape in response to different external stimuli such as heat, light, electricity, magnetism, even certain chemicals . This intriguing characteristic provides SMP a broad range of applications in smart packages, textiles, devices, and biomedical fields …”

Section: Introductionmentioning

confidence: 99%

Thermal induced shape‐memory and self‐healing of segmented polyurethane containing diselenide bonds

Jin

Pan

et al. 2018

J of Applied Polymer Sci

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Herein, we synthesized a series of polyurethane copolymers (PUs) with poly(1,4-butylene adipate) glycol as soft segment and 2,4-toluene diisocyanate as well as extenders including 1,4-butanediol and di(1-hydroxyethylene) diselenide as hard segment. The chemical structure, thermal property, crystallization behavior, shape memory, and self-healing performances of the PUs were systematically characterized by a series of experiments. It was found that the PU2 containing a higher diselenide component (33 mol %) exhibited both shape memory and self-healing behaviors under a moderate temperature (57 8C). Meanwhile, the PUs showed a good repeatability of shape memory function, and their fixity and recovery ratios were all above 90%. Additionally, the dynamic exchangeable feature of diselenide bonding endues the PUs chains with an acceptable reprocessability and self-healing performances, and the PU2 sample could be healed for five times by thermal treatment with the healing efficiencies above 70%. This work provides a heuristic perspective for the development of shape memory and self-healing materials. V C 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46326.

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“…13 In PU, the so segments further soen above T d and provide a feature of deformation; meanwhile, reversible stress can be programmed into the hard segments by reducing the temperature to below T d . 14,15 This underlying principle can be used to construct SMPs by blending two or more polymers with distinct reversible phase transitions. 16 A temporary shape can be programmed into a polymer composite when one component is so and the other remains stiff.…”

Section: Introductionmentioning

confidence: 99%

PU/PMMA composites synthesized by reaction-induced phase separation: a general approach to achieve a shape memory effect

Zhang¹,

Li²,

Wu³

et al. 2017

RSC Adv.

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Triple Shape Memory Effect of Star-Shaped Polyurethane

Cited by 78 publications

References 45 publications

pH-Responsive Shape Memory Poly(ethylene glycol)–Poly(ε-caprolactone)-based Polyurethane/Cellulose Nanocrystals Nanocomposite

pH-Responsive Shape Memory Poly(ethylene glycol)–Poly(ε-caprolactone)-based Polyurethane/Cellulose Nanocrystals Nanocomposite

Thermal induced shape‐memory and self‐healing of segmented polyurethane containing diselenide bonds

PU/PMMA composites synthesized by reaction-induced phase separation: a general approach to achieve a shape memory effect

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