Effect of thermoplasticizing elongation on the supermolecular structure of polymer fibres

Гинзбург, Б. М.; Tuichiyev, Sh.; Poveshchenko, A.G.; Frenkel, S.Ya.; Sorokin, A.Ya.

doi:10.1016/0032-3950(68)90353-5

Cited by 12 publications

(2 citation statements)

References 8 publications

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“…Therefore extraneous atoms can be accumulated in amorphous areas of polymer. In the same work [7] the formula is given which shows the direct proportionality between the intensity of small-angle scattering and the density of amorphous and crystal areas:…”

Section: Discussionmentioning

confidence: 99%

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Zinc oxide‐ and polymer‐based composite varistors

Hashimov

Hasanli

Mehtizadeh

et al. 2006

Phys. Status Solidi (c)

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This work reports on homogeneous varistor ceramics prepared from a mixture of impurity-doped zinc oxide (C) [E. Suzuki et al., IEEE Trans. Electron Dev. 47, 354 (2000); F.L. Souza et al., Mater. Chem. Phys. 80, 512 (2003)] and nonpolar polyethylene (PE) using a hot pressing method. The content of the composite components was varied from 10% (90%) to 70% (30%) of C (PE) and the thickness of the samples obtained was 40 or 150 µm. The voltage-current characteristics and electroconductivity with applied voltage were measured for all the samples obtained at room temperature. Also, the same samples were tested using infrared absorption and X-ray diffraction methods. As a result of these studies, the influence of ceramic composition on the ceramic parameters was established.

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Section: Discussionmentioning

confidence: 99%

“…For an explanation of the X-ray results, we note that according to [7], the intensity of small-angle scattering of an X-ray spectrum basically is defined by the density difference between the crystal and polymeric areas. Basically crystal areas of polymer are inaccessible to extraneous atoms.…”

Section: Discussionmentioning

confidence: 99%

Zinc oxide‐ and polymer‐based composite varistors

Hashimov

Hasanli

Mehtizadeh

et al. 2006

Phys. Status Solidi (c)

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Polymer fibers drawn to the limit

Slutsker¹,

Utevskii

1984

J. Polym. Sci. Polym. Phys. Ed.

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The orientational drawing of polymers is known to be terminated because of sample rupture. The limiting draw ratio λlim reached may be different (either large or small) depending on the polymer and the actual drawing conditions. The purpose of the present work is to identify the change of supermolecular structure of polymer fibers which results in the termination of orientational drawing. Small‐and wide‐angle x‐ray diffraction were used to study the variation of geometrical parameters of this structure with increasing draw ratio λ. The geometrical parameters discussed are the dispersions (fluctuation) of long periods and of longitudinal sizes of crystalline as well as amorphous regions. In this study we used fibers of poly(vinyl alcohol), poly(ε‐caprolactam), polyoxymethylene, and poly(4,4′‐diphenyloxide) pyromellitimide. It is found that the long period dispersion of these polymers, drawn under different conditions, increases to approximately the same value for different samples drawn to the limit, this relative standard deviation δL of long periods being 0.30‐0.40. It is also found that the crystallite size dispersion does not increase with increasing λ; the increase of λL is due to increasing dispersion of the amorphous region lengths. For poly(vinyl alcohol) fibers drawn to the limit under different conditions and which have different λlim, the relative standard deviation of the sizes of amorphous regions δA turned out to be about the same (ca. 0.60). The latter evidence gives grounds to suggest that the rupture of polymers under drawing is associated with reaching a high degree of amorphous region size dispersion. In those regions which are considerably below the average size there probably will appear local overstress and molecular ruptures because the relative deformation of these regions is much larger than that of the adjacent regions in the cross section of the sample.

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Morphological heterogeneity of polymer fibers which do not reveal small‐angle x‐ray reflections

Slutsker¹

1987

J Polym Sci B Polym Phys

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SynopsisFor many aliphatic and wholly aromatic polymer fibers, meridional small-angle x-ray reflections (SAXR's) are not observed. The morphological features which give rise to this effect have received little attention in the literature. I t is sometimes speculated that this is evidence of a morphological homogeneity along the fiber axis (no fluctuation of electron density-no long periods), ignoring other possible reasons (morphology is heterogeneous but very irregular or the maximum intensity of SAXR ( I -) is low and SAXR cannot be observed against the background of diffuse scattering.) Fibers with homogeneous crystalline morphology should have an elastic modulus E, clase to that of the crystallites E,, along the polymer chains over a broad range of stresses. Rut, as was found in this work for the overwhelming majority of such nonreflection fibers (including Kevlar aramid fibers) there is a considerable difference between E,, and E, (for some nonreflection fibers the ratio E,/E, is on the order of 10). This means that their morphology is heterogeneous along the fiber axis and contains "weaker" intercrystalline regions. This heterogeneity appeared to be regular enough to give rise to SAXR, as determined from the appearance of SAXR during elastic extension and after the beginning of pyrolysis in some nonreflection fibers. Thus, it was concluded that the lack of observable SAXR for these fibers is a result of the weakness of I,,relative to the diffuse scattering. Support for this statement is seen in the analysis of the decrease of I,,,, to zero with increasing draw ratio for poly(viny1 alcohol) fibers.The key factors influencing the decrease of I,, in this case were found to be the decrease of fibril diameter (fibril splitting), an increase of the dispersion of the long periods and some possible decrease in the density difference between crystalline and amorphous regions. The particular combinations of such factors can be different for each particular case of missing SAXR and are discussed in this paper.

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Effect of thermoplasticizing elongation on the supermolecular structure of polymer fibres

Cited by 12 publications

References 8 publications

Zinc oxide‐ and polymer‐based composite varistors

Zinc oxide‐ and polymer‐based composite varistors

Polymer fibers drawn to the limit

Morphological heterogeneity of polymer fibers which do not reveal small‐angle x‐ray reflections

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