Annealing of melt-crystallized nylon 6

Gogolewski, Sylwester; Gasiorek, M.; Czerniawska, K.; Pennings, A. J.

doi:10.1007/bf01419096

Cited by 31 publications

(35 citation statements)

References 14 publications

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“…78 These are associated with the increases in the density and crystallinity, the increases in the size, orientation, and density of the crystals, and the increases in the long period and the intensity of the corresponding lamellar peak (lamellar intensity). [84][85][86][87][88] However, these changes cannot be quantitatively predicted from the available structural models and the known crystallization behavior. One possible tack is to study the changes brought about by the onset of certain relaxation processes and the associated increase in the mobility that promote secondary crystallization, that is, the growth of existing crystallites perhaps epitaxially, and the formation of microcrystallites.…”

Section: Temperature Effectsmentioning

confidence: 99%

See 1 more Smart Citation

Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Murthy

2006

J Polym Sci B Polym Phys

218

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: Temperature Effectsmentioning

confidence: 99%

“…These changes begin to occur at 160-190 8C in PA-6. 78,85,[87][88][89][90][91] This could be due to crystalline chain relaxation that also accounts for premelting structural transitions, 87 the Brill transition being the most widely known among these. …”

Section: Temperature Effectsmentioning

confidence: 99%

Hydrogen bonding, mobility, and structural transitions in aliphatic polyamides

Murthy

2006

J Polym Sci B Polym Phys

218

197

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“…14, 15 Gurato et al 16 and Gogolewski et al 17 demonstrated the conversion of the crystal structure of nylon 6/clay nanocomposites by an annealing treatment. A similar phenomenon was also observed in nylon 66/clay nanocomposites.…”

Section: Introductionmentioning

confidence: 98%

Crystallization behavior of nylon 11/montmorillonite nanocomposites under annealing

Zhang

Yang

Lin

2006

J of Applied Polymer Sci

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Exfoliated nylon 11/montmorillonite (MMT) nanocomposites were prepared via in situ polymerization by the dispersion of organically modified MMT in 11-aminoundecanoic acid monomer. The polymorphic behavior of the nylon 11/MMT nanocomposites was investigated with X-ray diffraction, transmission electron microscopy, and Fourier transform infrared with attenuated total reflectance. MMT induced and stabilized the d-crystalline form of nylon 11. The crystal structure of nylon 11 was transformed from a hexagonal d-form structure to a triclinic a-form structure during the annealing process. Meanwhile, the hydrogen bonds in the nanocomposites also exhibited some differences from neat nylon 11 after annealing.

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“…Incorporation of comonomers/polymers into the backbone of the PA6 can also influence the packing of the chains [16]. In general, the ␣-form is dominant when the polymer is melt-crystallized at temperatures higher than 150 • C or slowly cooled, while quenching and low-temperature crystallization promote the formation of the ␥-form [10,12,[16][17][18]. The ␥-form can be transformed into the ␣-form via slow heating or annealing at an elevated temperature [11,19].…”

Section: Introductionmentioning

confidence: 99%

“…There are also other crystal forms of PA6 reported in literature, which are mainly variations of these two crystal forms, however, most of them are not stable [4,[6][7][8][9]. The molecular packing of PA6 is highly dependent on processing conditions, thermal treatment, applied stress and presence of moisture and additives [5,[10][11][12][13]. It is well known that the ␣-form can be transformed into the ␥-form by treatment with an aqueous iodine/potassium iodide solution [14,15].…”

Section: Introductionmentioning

confidence: 99%