Polymers with Aromatic Rings in the Chain

Critchley, J. P.; Knight, G. J.; Wright, W. W.

doi:10.1007/978-1-4899-0396-9_4

Cited by 2 publications

(2 citation statements)

References 44 publications

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“…This demands a backbone structure with strong chemical bonding and intermolecular interactions. 29 All of these attributes are naturally against stretchability and therefore potentially reduce toughness. To address this challenge, we show that by controlling the structural relaxation of aramid nanofibers (ANFs), which we first demonstrated as an attractive high-performance nanoscale building unit, 30 ultratough crimped aramid fibers can be synthesized with a stretchability up to 163%.…”

Section: Introductionmentioning

confidence: 99%

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Controlled Structural Relaxation of Aramid Nanofibers for Superstretchable Polymer Fibers with High Toughness and Heat Resistance

Ji,

Feng,

Yang

2024

ACS Nano

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Polymer fibers that combine high toughness and heat resistance are hard to achieve, which, however, hold tremendous promise in demanding applications such as aerospace and military. This prohibitive design task exists due to the opposing property dependencies on chain dynamics because traditional heat-resistant materials with rigid molecular structures typically lack the mechanism of energy dissipation. Aramid nanofibers have received great attention as highperformance nanoscale building units due to their intriguing mechanical and thermal properties, but their distinct structural features are yet to be fully captured. We show that aramid nanofibers form nanoscale crimps during the removal of water, which primarily resides at the defect planes of pleated sheets, where the folding can occur. The precise control of such a structural relaxation can be realized by exerting axial loadings on hydrogel fibers, which allows the emergence of aramid fibers with varying angles of crimps. These crimped fibers integrate high toughness with heat resistance, thanks to the extensible nature of nanoscale crimps with rigid molecular structures of poly(p-phenylene terephthalamide), promising as a template for stable stretchable electronics. The tensile strength/modulus (392−944 MPa/11−29 GPa), stretchability (25−163%), and toughness (154−445 MJ/cm 3 ) are achieved according to the degree of crimping. Intriguingly, a toughness of around 430 MJ/ m 3 can be maintained after calcination below the relaxation temperature (259 °C) for 50 h. Even after calcination at 300 °C for 10 h, a toughness of 310 MJ/m 3 is kept, outperforming existing polymer materials. Our multiscale design strategy based on water-bearing aramid nanofibers provides a potent pathway for tackling the challenge for achieving conflicting property combinations.

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Section: Introductionmentioning

confidence: 99%

“…To integrate high toughness with heat resistance, polymers with an inherently superior thermal stability are therefore the ideal choice. This demands a backbone structure with strong chemical bonding and intermolecular interactions . All of these attributes are naturally against stretchability and therefore potentially reduce toughness.…”

Section: Introductionmentioning

confidence: 99%

Controlled Structural Relaxation of Aramid Nanofibers for Superstretchable Polymer Fibers with High Toughness and Heat Resistance

Ji,

Feng,

Yang

2024

ACS Nano

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New Polymer Syntheses Part 56: Novel Friedel-Crafts Polyketones Containing Naphthalene Moiety: Synthesis, Characterization and Antimicrobial Activity

Hussein

Abdelrahman

Aly

2012

Journal of Macromolecular Science, Part A

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Novel Friedel-Crafts polyketones containing naphthalene moiety were synthesized via the electrophilic Friedel-Crafts polycondensation method. The desired polyketones were obtained by the interaction of newly synthesized dinaphthylidenecycloalkanone monomers with different aliphatic and aromatic diacid chlorides. The structures of new monomers and polymers were confirmed by elemental and spectral analyses, besides X-ray single crystal data for the two new monomers. The new polyketones were characterized by solubility, viscometry, thermal properties, scanning electron microscopy and antimicrobial activity test. All the polyketones were soluble in formic acid as protonic solvent giving yellowish to brown colors. Some of the polyketones were partially soluble in n-hexane, benzene and chloroform. The thermal properties of those polymers were evaluated by TGA; DTG and DTA measurements. The desired polyketones have high thermal stability at T 10 except polymer 3 b which have low T 10 value. FDT for all polyketones is nearly completed at around 522-677 • C. The morphological properties of polyketone 2 b were tested by SEM measurements. The synthesized monomers and polymers were screened for their antibacterial and antifungal activities. They showed a moderated antibacterial activity against tested Gram-negative and Gram-positive bacteria and no significant influence against the selected fungi species except monomer 1 b and polymers 2 a , 3 b .

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Polymers with Aromatic Rings in the Chain

Cited by 2 publications

References 44 publications

Controlled Structural Relaxation of Aramid Nanofibers for Superstretchable Polymer Fibers with High Toughness and Heat Resistance

Controlled Structural Relaxation of Aramid Nanofibers for Superstretchable Polymer Fibers with High Toughness and Heat Resistance

New Polymer Syntheses Part 56: Novel Friedel-Crafts Polyketones Containing Naphthalene Moiety: Synthesis, Characterization and Antimicrobial Activity

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