Effect of hydrogen bonding on the anisotropy of the hydrostatic compressibility of polymer crystals

Ito, Takashi; Hirata, Takaki; Fujita, Shinsuke

doi:10.1002/pol.1979.180170708

Cited by 14 publications

(6 citation statements)

References 14 publications

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“…33 The linear compressibility normal to the hydrogen-bonded sheets is 4.3 times that in the parallel direction. 34 The ionic character of the hydrogen bonds, resulting from a partial transfer of the electron from the hydrogen to oxygen, and the electrostatic attraction between the electric dipoles contribute to the strength of the amide-amide interactions. 2,31 It is quite possible that the destruction of the dipolar interactions contribute to the glass transition and melting, and the breaking of the hydrogen bonds requires melting and hydrolysis.…”

Section: Structure Crystalline Structurementioning

confidence: 99%

Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Murthy

2006

J Polym Sci B Polym Phys

215

197

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Some salient results in nylon research are reviewed to identify the fundamental principles that are applicable to other strongly interacting or hydrogenbonded polymers, including proteins. The effects of hydrogen bonds on stress-, heat-, and solvent-induced changes in macroscopic properties are discussed. These data provide a window into the chain mobility and linkages between the crystalline and amorphous domains, both of which are important for any predictive model. The changes in the characteristics of the amorphous phase with the crystallinity and orientation require that it be modeled with at least two components: a rigid/immobile/ anisotropic component and a soft/ mobile/isotropic component. The deformation and shrinkage behavior of these polymers are discussed in terms of the relative contributions of the amorphous and crystalline domains and of the interactions between them. The premelting crystalline transition is accompanied by the merging of intersheet and intrasheet diffraction peaks in some nylons, as observed by Brill, and not in others even though the underlying mechanism that gives rise to these transitions, the onset of volume-increasing librational motion of the crystalline stems, is the same. Because the effects of the temperature, deformation, and solvent have a common origin associated with mobility, a fictive temperature can be associated with a given solvent activity or stress level. The magnitude of this fictive temperature is the amount by which the glass or Brill transition temperature is reduced in the presence of solvents ($50 8C) or stress or by which the annealing temperature can be reduced in the presence of a solvent (or active stress) to achieve the same structural state as that of a dry (or static) polymer.

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Section: Structure Crystalline Structurementioning

confidence: 99%

Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Murthy

2006

J Polym Sci B Polym Phys

215

197

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“…20 have reported that in the y form crystal, pressure induces an elongation in the fiber axis direction at room temperature. This means that the molecular chains in the y form, where there is considerable deviation from the planar conformation in the amide group of the chain, tend to take on a planar zigzag-like conformation under high pressure.…”

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confidence: 99%

Melting and Transformation Behavior of γ Form Nylon 6 under High Pressure

Hiramatsu

Hirakawa

1982

Polym J

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ABSTRACT:Thermal behavior under high pressure of the y form nylon 6 obtained by iodine treatment was investigated by means of a high pressure differential thermal analysis. The crystalline structures which resulted in the endo-and exo-thermic peaks in the thermogram were examined with the wide angle X-ray diffraction measurement. Under relatively low pressure kg em-2 ), two endothermic peaks were found. With increasing pressure, the lower temperature side endotherm due to the melting of the y form crystal became small, while the higher one due to the melting of the converted rx form crystal became large. Under high pressure (above 2000 kg em -z) an endotherm due to the melting of the converted rx form crystal and an exotherm were observed. This exotherm is attributed to they to rx form transformation. In this case, the transformation occurred without melting the y form crystal, in contrast to the situation at atmospheric pressure. The pressure dependences of the melting peak temperatures of the rx form and they form were almost the same and equal to !Soc per 1000 kg em-2 •

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“…14,15 Particularly, polymers possess underlying stimulus-responsive features, which allow them to undergo a conformational change or coil-to-globule transition upon changes in external stimuli such as temperature, counterions, pH, electricity and light. [16][17][18][19][20] Amid stimulus-responsive polymers, thermoresponsive polymers have been extensively studied in academic and applied polymer sciences over the last decades. 10,[17][18][19][20][21][22] A thermoresponsive polymer undergoes a change in solubility in a polymer-solvent system with varying temperatures.…”

Section: Xirui LImentioning

confidence: 99%