Investigation of morphological aspects and thermal properties of ZnO/poly(amide–imide) nanocomposites based on levodopa-mediated diacid monomer

Ahmadi, Mehdi; Rad‐Moghadam, Kurosh; Hatami, Mehdi

doi:10.1007/s00289-018-2366-2

Cited by 8 publications

(5 citation statements)

References 36 publications

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“…Subsequently, poly(amic acid) was dissolved in THF and refluxed at 66 °C overnight for imidization. After removal of the solvent, imidization was then completed by heating at 80 °C i n vacuo for 15 h. After drying, Fourier transform infrared (FTIR) spectroscopy was performed to verify formation of imide from the appearance of bands at 1780 and 1725 cm –1 (see SI Figure S7) and further confirmed by 1 H NMR spectra of poly(amic acid) and polyimide (see SI Figure S2). The number-average molar mass, M n , of the linear polyimide was determined with size-exclusion chromatography in THF (see SI Figure S8) to be 20 kg·mol –1 relative to polystyrene standards.…”

Section: Resultsmentioning

confidence: 99%

Dynamic Polyamide Networks via Amide–Imide Exchange

et al. 2021

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The diamide–imide equilibrium was successfully exploited for the synthesis of dynamic covalent polymer networks in which a dissociative bond exchange mechanism leads to high processibility at temperatures above ≈110 °C. Dynamic covalent networks bridge the gap between thermosets and thermoplastic polymers. At the operating temperature, when the network is fixed, dynamic covalent networks are elastic solids, while at high temperatures, chemical exchange reactions turn the network into a processible viscoelastic material. Upon heating a dissociative network, the viscosity may also decrease due to a shift of the chemical equilibrium; in such materials, the balance between processibility and excessive flow is important. In this study, a network is prepared that upon heating to above ≈110 °C dissociates to a significant extent due to a shift in the amide–imide equilibrium of a bisimide, pyromellitic diimide, in combination with poly(tetrahydrofuran) diamines. At room temperature, the resulting materials are elastic rubbers with a tensile modulus of 2–10 MPa, and they become predominantly viscous above a temperature of approximately 110 °C, which is dependent on the stoichiometry of the components. The diamide–imide equilibrium was studied in model reactions with NMR, and variable temperature infrared (IR) spectroscopy was used to investigate the temperature dependence of the equilibrium in the network. The temperature-dependent mechanical properties of the networks were found to be fully reversible, and the material could be reprocessed several times without loss of properties such as modulus or strain at break. The high processibility of these networks at elevated temperatures creates opportunities in additive manufacturing applications such as selective laser sintering.

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Section: Resultsmentioning

confidence: 99%

Dynamic Polyamide Networks via Amide–Imide Exchange

et al. 2021

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“…This results in improved photoabsorption in the visible range and increased photocurrent density. [ 33,35,39,64,75,87,92 ] Other spectroscopic techniques used for the characterization of metal oxide/catechol systems include NMR spectroscopy for determining whether catechol‐type ligands link other molecules, [ 93 ] Raman spectroscopy for quantifying the amount of catechol ligand bonded to metal oxide nanostructure surface, [ 68,79 ] and photoemission spectroscopy for experimentally obtaining the occupied and unoccupied states of the adsorbed catechol ligands. [ 41 ] TGA studies allow for the calculation of the maximum grafting density of ligands, adsorption coefficient, and negative‐free binding energies of the surface functionalization of metal oxide nanostructures.…”

Section: Characterization Of Metal Oxide/catechol Systemsmentioning

confidence: 99%

Surface Functionalization of Metal Oxide Semiconductors with Catechol Ligands for Enhancing Their Photoactivity

et al. 2021

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Metal oxide nanostructures are increasingly important materials for various emerging photocatalytic, photovoltaic and photoelectrochemical (PEC) applications. They are commonly used as photoelectrode materials due to their unique functional properties such as wide bandgap, reactive electronic transitions, and high stability. To increase the effectiveness of semiconductor metal oxides photoelectrodes, researchers seek to use various photoabsorption amplification and colloidal stability enhancement strategies. An effective method for achieving this is the surface functionalization of metal oxide semiconductors with catechol‐type ligands. Catechol‐type ligands are a family of organic molecules that adsorb very strongly onto metal oxides by forming complexes with metal atoms through adjacent phenolic —OH groups. Once adsorbed, catechol‐type ligands facilitate improved particle dispersion by inhibiting agglomeration and enhance photoexcitation in metal oxide semiconductors by improving visible light absorption. Herein, the surface complexation of catechol‐type ligand onto metal oxide semiconductor surfaces and their photoabsorption enhancement mechanisms is described. In addition, recent advances and trends in this area are described by presenting recent advancements made in applications of catechol‐modified metal oxide systems in photocatalysis, PEC biosensing, and solar cells.

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“…The morphology of different elaborated composite (PGE-PBAP/MDA/PN) without and with natural phosphate incorporated in the epoxy matrix was determined by using the polarizing optical microscope (Fig. 11) [27,28]. The morphology of the prepared composite varied greatly with the different percentages of the natural phosphate incorporated into pentafunctional epoxy resin PGEPBAP.…”

Section: Morphology Of Composite (Pgepbap/mda/pn)mentioning

confidence: 99%

Investigation of structure and rheological behavior of a new epoxy polymer pentaglycidyl ether pentabisphenol A of phosphorus and of its composite with natural phosphate

et al. 2019

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Novel pentafunctional epoxy resin, mainly based on pentaglycidyl ether pentabisphenol A of phosphorus (PGEPBAP) has been synthesized and characterized through different spectroscopic methods (FTIR, 1 H NMR, 13 C NMR and 31 P NMR). Moreover, the analysis of the viscosity of (PGEPBAP/Methanol) system was determined by using viscosimeter VB-1423 of the Ubbelohde type. Furthermore, the analysis of the rheological properties of the matrix PGEPBAP and their (PGEPBAP/ MDA/PN) elaborated composite was performed according the RHM01-RD HAAKE rheometer. In addition, the morphology of different (PGEPBAP/MDA/PN) prepared composite was determined by using the polarizing optical microscope.

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Investigation of morphological aspects and thermal properties of ZnO/poly(amide–imide) nanocomposites based on levodopa-mediated diacid monomer

Cited by 8 publications

References 36 publications

Dynamic Polyamide Networks via Amide–Imide Exchange

Dynamic Polyamide Networks via Amide–Imide Exchange

Surface Functionalization of Metal Oxide Semiconductors with Catechol Ligands for Enhancing Their Photoactivity

Investigation of structure and rheological behavior of a new epoxy polymer pentaglycidyl ether pentabisphenol A of phosphorus and of its composite with natural phosphate

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