Structural changes accompanying hydration in nylon 6

Murthy, N. Sanjeeva; Stamm, Manfred; Sibilia, J. P.; Krimm, Samuel

doi:10.1021/ma00193a043

Cited by 144 publications

(165 citation statements)

References 13 publications

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“…5,42 Most importantly, they have provided unambiguous confirmation of the IR results showing that the hydrogen bonds are weaker in the a form than in the c form (27 meV vs 32.5 and 37 meV for the torsional vibration about the CÀ ÀN bond, amide VII mode). 5,39 IR data that show the hydrogen bonds in the amorphous phase to be similar to those in the c phase lead to the suggestion that the hydrogen bonds between the chains in the a phase are weaker than those in the amorphous phase. The conformation of the amide group influences both the strength of the hydrogen bonds and the chain-axis repeat.…”

Section: Structure Crystalline Structurementioning

confidence: 99%

“…38 At room temperature, the crystalline stems resist dueteration. [38][39][40][41] Full exchange occurs at elevated temperatures (140-150 8C) in the presence of water. The hydrogen-deuterium exchange is reversible only when it occurs in the amorphous regions and is not when this exchange is accompanied by crystallization.…”

Section: Structure Crystalline Structurementioning

confidence: 99%

“…The hydrogen-deuterium exchange is reversible only when it occurs in the amorphous regions and is not when this exchange is accompanied by crystallization. 39 In general, the exchange can be reversed only under conditions more severe than those during previous conditioning of the sample. 39,41 Inelastic neutron scattering measurements have also provided valuable information on the nature of the various amide modes.…”

Section: Structure Crystalline Structurementioning

confidence: 99%

“…39 In general, the exchange can be reversed only under conditions more severe than those during previous conditioning of the sample. 39,41 Inelastic neutron scattering measurements have also provided valuable information on the nature of the various amide modes. 5,42 Most importantly, they have provided unambiguous confirmation of the IR results showing that the hydrogen bonds are weaker in the a form than in the c form (27 meV vs 32.5 and 37 meV for the torsional vibration about the CÀ ÀN bond, amide VII mode).…”

Section: Structure Crystalline Structurementioning

confidence: 99%

“…Water transforms the pseudohexagonal crystalline phase in PA-66 (not the high-temperature Brill phase) to a triclinic a phase. 113 Moisture that enables PA-6 to crystallize preferentially in the a-crystalline form at ambient temperatures 39,114 causes it to crystallize completely in the a form at high temperatures and even brings about transformation of the c form into the a form. 28,105,115 Because water (solvent) molecules diffuse preferentially into the amorphous regions, these data show that the interactions between the crystalline stems and amorphous segments are bidirectional; that is, an increase in the mobility of the amorphous chains can affect the motion of the crystalline stems.…”

Section: Interaction Between Amorphous and Crystalline Domainsmentioning

confidence: 99%

See 4 more Smart Citations

Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Murthy

2006

J Polym Sci B Polym Phys

222

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%

Section: Structure Crystalline Structurementioning

confidence: 99%

Section: Structure Crystalline Structurementioning

confidence: 99%

Section: Structure Crystalline Structurementioning

confidence: 99%

Section: Interaction Between Amorphous and Crystalline Domainsmentioning

confidence: 99%

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Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Murthy

2006

J Polym Sci B Polym Phys

222

197

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Polyamide Fibres

2015

Physico‐chemical Aspects of Textile Coloration

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SAXS study of polyamide 6 swollen in methanol

Baldrián

Pleštil

1991

Acta Polymerica

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VIw effect of tlic annealing teinperature on the structure of unoricnted 1ut.yainidc 6 was studied by swelling in methanol ;ind sinnll-anglc X-ray scatteiiiig. Tlic observed values of mean-square fluctuations of scattering density can be c.splaiiiet1 1)s using 11 rnotlel with aii iiiliornogerieously swelling amorphous phase. An increase in the annealing tempcriiture iiiiprovcbs tlic iiitcriial structure of tlie lairiellae atid reduces coarseness of tlicir surface. The conceutration o f pnlynit*r cli;iiiis in the ceiitri. o f the swollen amorphous interlayer strongly tlccreases. SLLSS-~~rrter.siic.tiurigeti u n irr hlr!/iunol gepollenem Pvlyurtiiil GI k r l < i d l t d \ t l e r Teriipertcrlipel.:itiir auf die Struktiir von iinorienticrtcrn I'olyaniid fi wiirile diircli Quellung iu Metliaiiol iriid Huiitgenkleiiiwiiikelstreuuiig untersuclit. Die gefuntlenen Werte dcr niittlereii quadratisclien I~luktuationcn der Streiiilictite kiiiiiieii durcli eiii Moclell iriit ciner inlioinogen quellcntlcn amorplien Phase erklirt werden. Die Erholiung cler Teliil"'tcniperatiir verbcssert die innerc Struktiii. iler Lariiellen uriil verringert die Rauliigkeit ilti-cr Oberfliiclie. Uiv I

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Structural changes accompanying hydration in nylon 6

Cited by 144 publications

References 13 publications

Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Polyamide Fibres

SAXS study of polyamide 6 swollen in methanol

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