The Raman spectra of uniaxially oriented isotactic polypropylene

Bailey, R. T.; Hyde, A. J.; Kim, J.J.

doi:10.1016/0584-8539(74)80214-x

Cited by 33 publications

(12 citation statements)

References 8 publications

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“…As seen in Table I Assignment of these A, modes is supported by consulting the X ( 2 X ) Y spectra, in which the A, modes are expected to exhibit diminished intensity. For this geometry, calculation of the derived orientation-averaged polarizabilities, a&, according to eq 2 using a transformation matrix @, determined from the relationship between molecular and laboratory axes shown in Figure 2, gives azzz = %(ayy' + 2 /~~y y a , z + a,,') + 1/ayr2 (geometry 2) If this expression is compared with that obtained for the X ( Y X ) Y experiment in geometry 1 (Figure 1) (geometry 1) only the last term, contributes identically to the two spectra and is the sole contributor of intensity to the B, modes in these two expressions. For this reason, a second scattering geometry (no.…”

Section: Assignmentsmentioning

confidence: 99%

Structural characterization of an ethylene-tetrafluoroethylene alternating copolymer by polarized Raman scattering

Zabel¹,

Schlotter²,

Rabolt³

1983

Macromolecules

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The anisotropic scattering properties of a uniaxially oriented filament of an ethylene-tetrafluoroethylene (E-TFE) alternating copolymer have been investigated in order to determine the molecular conformation in ordered crystalline regions. Both a trans-planar and a 312-helical structure have been shown to be energetically possible in an isolated molecule and in this study the group theoretical analyses for these structures are presented. Comparison of these results with polarized Raman measurements indicates that the copolymer backbone crystallizes in predominantly a planar-zigzag structure. Observation of the low-frequency Raman-active longitudinal acoustical mode (LAM) and the correlation of its frequency position with the crystalline stem length obtained from SAXS and crystallinity measurements strongly support the trans-planar structure.

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Section: Assignmentsmentioning

confidence: 99%

Structural characterization of an ethylene-tetrafluoroethylene alternating copolymer by polarized Raman scattering

Zabel¹,

Schlotter²,

Rabolt³

1983

Macromolecules

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“…Second‐order Raman lines14, 28–32 are also noticed (see Fig. 1); the line located at about 2600 cm −1 has been assigned to the D* mode, whereas the 2Γ mode located about 3200 cm −1 has not been observed.…”

Section: Resultsmentioning

confidence: 93%

“…Second-order Raman lines 14,[28][29][30][31][32] are also noticed (see Figure 1); the line located at about 2600 cm -1 has been assigned to the D* mode, whereas the 2Γ mode located about 3200 cm -1 has not been observed. The D″ line reported in some carbon nanofibers and located at about 1500 cm -1 has not been observed.…”

Section: Resultsmentioning

confidence: 97%

“…Several lines, originating from the VGCNF dispersed within the polymeric matrix were easily identified; first‐order Raman spectra include9–16, 14, 28–32 the line located at about 1320 cm −1 , identified as the D‐mode and the line located at 1590 cm −1 , identified as the G‐mode. The D‐mode is dispersive, that is, the Raman line position depends on the frequency of the laser beam.…”

Section: Resultsmentioning

confidence: 99%

“…The D″ line reported in some carbon nanofibers and located at about 1500 cm -1 has not been observed. 14,28,29,33 A weak line located between 1420 and 1470 cm -1 , has been noticed and tentatively assigned to band modes about K or M points. 29 These lines are enhanced as the loading with VGCNF is increased.…”

Section: Resultsmentioning

confidence: 99%

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Spectroscopic investigations on polypropylene‐carbon nanofiber composites. I. Raman and electron spin resonance spectroscopy

Chipara¹,

Villarreal²,

Chipara³

et al. 2009

J Polym Sci B Polym Phys

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Isotactic polypropylene‐vapor grown carbon nanofiber composites containing various fractions of carbon nanofibers, ranging from 0 to 20 wt %, have been prepared. Raman spectroscopy was used to analyze the effect of the dispersion of carbon nanofibers within polypropylene and the interactions between carbon nanofibers and macromolecular chains. The as‐recorded Raman spectra have been successfully fitted by a linear convolution of Lorentzian lines. Changes of the Raman lines parameters (position, intensity, width, and area) of polypropylene and carbon nanofibers were analyzed in detail. The Raman spectra of the polymeric matrix—at low concentrations of nanofibers—show important modifications that indicate strong interactions between carbon nanofibers and the polymeric matrix reflecting by vibrational dephasing of macromolecular chains. The Raman spectrum of carbon nanofibers is sensitive to the loading with carbon nanofibers, showing changes of the resonance frequencies, amplitudes, and width for both D‐ and G‐bands. Raman data reveals the increase of the disorder, as the concentration of carbon nanofibers is increased. The presence of the typical ESR line assigned to conducting electrons delocalized over carbon nanofibers is confirmed and the presence of a spurious magnetic line due to catalyst's residues is reported. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1644–1652, 2009

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Vibrational Spectroscopy

Hsu¹

2002

Encyclopedia of Polymer Science and Technology

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This article presents various applications of vibrational spectroscopy for analysis of polymer structure. The relative merits of vibrational spectroscopy versus other techniques for characterization of polymer structure are discussed. Special emphasis is given to analysis of chain configuration, conformation, interchain interactions, crystallization behavior, and crystalline region size. Experimental data combined with data provided by normal coordinate analysis were utilized in analysis of spectroscopic features associated with disordered chains. Specialized topics such as amount of free volume, phase transformation, microspectroscopy, segmental orientation, and surface analysis are presented. Analysis of structural dynamics using double modulation spectroscopy and time resolved spectroscopy is also addressed.

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The Raman spectra of uniaxially oriented isotactic polypropylene

Cited by 33 publications

References 8 publications

Structural characterization of an ethylene-tetrafluoroethylene alternating copolymer by polarized Raman scattering

Structural characterization of an ethylene-tetrafluoroethylene alternating copolymer by polarized Raman scattering

Spectroscopic investigations on polypropylene‐carbon nanofiber composites. I. Raman and electron spin resonance spectroscopy

Vibrational Spectroscopy

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