Temperature-induced changes in chain-folded lamellar crystals of aliphatic polyamides. Investigation of nylons 2 6, 2 8, 2 10, and 2 12

Jones, Nathan; Cooper, Sharon J.; Atkins, E. D. T.; Hill, M. J.; Franco, Lourdes

doi:10.1002/(sici)1099-0488(199703)35:4<675::aid-polb14>3.0.co;2-d

Cited by 72 publications

(132 citation statements)

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“…92 This behavior has been observed in many other nylons. [93][94][95][96][97] Figure 9 shows some recent examples of such results. The first peak at 2h$208 corresponds to the intrasheet distances between the hydrogen-bonded chains, and the second peak at 2h$248 corresponds to intersheet distances.…”

Section: Premelting Transitionsmentioning

confidence: 96%

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: Premelting Transitionsmentioning

confidence: 96%

Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Murthy

2006

J Polym Sci B Polym Phys

215

197

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“…Above behavior of the molecular chain packing is often observed for other nylon below the Brill transition. On heating, the crystalline phase transition, the so-called Brill transition, is observed in aliphatic nylons [4,5,19,20]. The Brill transitions of various nylons have been extensively studied [21][22][23].…”

Section: Temperature Variation Of the Crystal Structure In The Scsmentioning

confidence: 99%

“…The crystal structures for aliphatic nylons have been widely investigated [1][2][3][4][5]. Generally, the  form appears in the crystals of even-even nylons [1,6].…”

Section: Introductionmentioning

confidence: 99%

Polymorphism of poly(nonamethyleneoxamide) crystal

Nakagawa

Nozaki

Maeda

et al. 2015

Polymer

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The crystal structures of poly(nonamethyleneoxamide) (nylon-9,2) were investigated by wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry. Nylon-9,2 shows a polymorphism with two different structures depending on the conditions of sample preparation.Monoclinic form I is the dominant crystalline phase for the solution-crystallized sample. For melt-crystallized samples, form I and new monoclinic form I′ coexist. Variable-temperature WAXD measurements were used to investigate the stability of each crystal form and the phase transition. Form I does not undergo any phase transitions prior to melting, although the orthorhombic molecular chain packing in form I at low temperature comes close to the quasihexagonal one during the heating process. Form I′ shows no phase transition on heating until its melting, too. The crystal lattice simply expands due to the thermal expansion. Form I is believed to be more stable, because the melting temperature of form I is higher than that of form I′.

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“…[1] In recent years, it has been found that several even-even nylons and even nylons also display Brill transition. [2][3][4][5][6] However, the mechanism of the transition has not been fully understood yet. Two models were proposed to explain the transition process.…”

Section: Introductionmentioning

confidence: 99%