Synthesis and properties of liquid crystalline copolyarylates containing phenylhydroquinone

Higashi, Fukuji; Kim, Ji‐Hwan; Ong, Chen-Han

doi:10.1002/(sici)1099-0518(19990301)37:5<621::aid-pola12>3.0.co;2-a

Cited by 14 publications

(11 citation statements)

References 14 publications

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“…A great deal of research on PAEKs has been concentrated on the introduction of pendant groups to improve the solubility, processability, and other desired properties. To meet various demands without thermal stability being sacrificed, PAEKs with phenyl, methyl, butyl, and bromomethyl side groups have been successfully prepared 4–7…”

Section: Introductionmentioning

confidence: 99%

Poly(aryl ether ketone)s with (3‐methyl)phenyl and (3‐trifluoromethyl)phenyl side groups

Liu

Wang

et al. 2002

J. Polym. Sci. A Polym. Chem.

112

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New bisphenol monomers, (3‐methyl)phenylhydroquinone and (3‐trifluoromethyl)phenylhydroquinone, were prepared in a two‐step synthesis. A series of poly(aryl ether ketone)s were derived from these bisphenols via a nucleophilic aromatic substitution polycondensation with various bisfluoro compounds. The polycondensation proceeded quantitatively in tetramethylene sulfone in the presence of anhydrous potassium carbonate and afforded the polymers with inherent viscosities of 0.63–0.91 dL/g. The fluorinated polymers showed lower glass‐transition temperatures and higher thermal‐decomposition temperatures than the corresponding nonfluorinated polymers. The solubility of the polymers was improved by the introduction of bulky pendant groups. All the polymers formed transparent, strong, and flexible films, with tensile strengths of 86.4–102.0 MPa, Young's moduli of 2.28–3.03 GPa, and elongations at break of 14–42%. All the polymers had low dielectric constants of 2.70–2.83 at 1 MHz. Compared with the methylated polymers, the trifluoromethylated polymers exhibited lower water sorption, which was attributed to the stronger hydrophobicity of the fluorine‐containing groups. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3392–3398, 2002

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Section: Introductionmentioning

confidence: 99%

Poly(aryl ether ketone)s with (3‐methyl)phenyl and (3‐trifluoromethyl)phenyl side groups

Liu

Wang

et al. 2002

J. Polym. Sci. A Polym. Chem.

112

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“…Therefore, a great deal of effort has been expended to try to improve the processing characteristics of the relatively intractable polymers. [2][3][4][5][6][7][8][9][10][11] Introduction of pendent loops along the polymer backbone has been shown to impart greater solubility and enhanced rigidity as well as better mechanical and thermal properties to the resulting cardo polymer, which is of particular importance in aromatic heterocyclic polymers with rigid chains. 12 It has been reported that the presence of cardo groups such as fluorene, phthalide, phthalimidine, and anthrone in the repeat unit of polyester results in enhanced solubility as well as high thermal properties of polymer.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of new soluble polyesters derived from various cardo bisphenols by solution polycondensation

Liaw

Hsu

et al. 2000

J. Polym. Sci. A Polym. Chem.

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“…However, polyarylates are generally difficult to process because of their limited solubility in organic solvents and their high melting temperatures or high glass transition temperatures ( T g 's) by virtue of their rigid structures. Therefore, a great deal of effort has been expended to try to improve the processing characteristics of the relatively intractable polymers 2–11…”

Section: Introductionmentioning

confidence: 99%

Soil Seed Banks and Forest Succession Direction Reflect Soil Quality in Ziwuling Mountain, Loess Plateau, China

Cheng

Shao

et al. 2011

CLEAN Soil Air Water

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The paper presents a study by taking the soil seed banks and vegetation successions of the forests in Ziwuling Mountain as indicators to analyze the effects of the ages, and the litter layers and soil depths at growing locations in seven types of forest communities on their seed bank formations and soil quality. The results showed that the seed banks at different growing locations in the communities increased in the order of upper slope, middle slope, and lower slope; the seed storages of the seed banks in the different layers of the communities varied, much more higher in the litter layers than in 0-15 cm, and the seed storages of the seed banks in the seven types of forest communities ranked in the increasing order of Pinus tabulaeformis forest, Pinus shenkaneusis forest, Quercus liaotungensis forest, Populus davidiana forest, Betula platyphylla forest, scrub communities, and grassland communities; in the meantime, the seed storage of seed banks peaked in 30-50 years old P. shenkaneusis forest, 30-40 years old P. tabulaeformis forest, 15-30 years old Q. liaotungensis, and P. davidiana and B. platyphylla forests, and 10-15 years old scrub and grassland communities, and the ages of the communities varied with the seed storages of the seed banks in a significantly correlative manner following a fitted exponential equation. In addition, the soil seed banks of the seven types of communities consisted of rich and diverse species with the herbaceous and shrub species greatly outnumbering the arbor species; in general, the coniferous forests were composed of 31 kinds of plants, the deciduous and broadleaf forests consisted of 20-29 plant species, the shrubs contained 27 plant species, and the herbaceous plants numbered 20 plant species; The various species compositions contained only 4-6 arbor species with most being foreign species. In each of the compositions, Bothriochloa ischemum was the grassland plant with the highest occurrence frequency, Sophora viciifolia and Hippophae reamnoides were the shrub plants with the highest occurrence frequencies, and Q. liaotungensis was the arbor plant with the highest occurrence frequency, and they followed by P. shenkaneusis and P. tabulaeformis. These results showed that soil seed banks and forest successions are better indicators for soil quality from natural successions.

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Synthesis and properties of liquid crystalline copolyarylates containing phenylhydroquinone

Cited by 14 publications

References 14 publications

Poly(aryl ether ketone)s with (3‐methyl)phenyl and (3‐trifluoromethyl)phenyl side groups

Poly(aryl ether ketone)s with (3‐methyl)phenyl and (3‐trifluoromethyl)phenyl side groups

Synthesis and characterization of new soluble polyesters derived from various cardo bisphenols by solution polycondensation

Soil Seed Banks and Forest Succession Direction Reflect Soil Quality in Ziwuling Mountain, Loess Plateau, China

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