Raman scattering from the longitudinal acoustic mode in crystalline poly(ethylene oxide)

Hartley, A.J.; Leung, Y.K.; Booth, Colin; Shepherd, I.W.

doi:10.1016/0032-3861(76)90197-x

Cited by 70 publications

(26 citation statements)

References 7 publications

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“…Within experimental error the widths of the GPC curves were unchanged by cyclization and methylation: analysis gave values of M w/Mn in the range 1.07 ( 0.03 without correction for instrumental spreading; see Table 2. 13 C spectra, using solutions of ca. 5 wt % in CDCl3.…”

Section: Methylationmentioning

confidence: 99%

“…We have repeated their procedure many times without success. Our method of proof of cyclization is unambiguous, being based on 13 C NMR spectroscopy and the absence of resonances characteristic of hydroxy end groups (see section 2.4 for details). We have consistently found almost complete recovery of precursor glycol.…”

Section: Introductionmentioning

confidence: 99%

“…Much is known about the crystallinity of low-molar-mass linear poly(oxyethylene)s, for example through early studies by X-ray scattering, , Raman spectroscopy, , and differential scanning calorimetry. , Poly(ethylene glycol)s [α-hydro,ω-hydroxypoly(oxyethylene)s] with narrow molar mass distributions ( M w / M n ≤ 1.1) and M n ≤ 20000 g mol -1 are available from a number of manufacturers. In the present work, these materials were used as precursors for preparation of cyclic poly(oxyethylene)s and poly(oxyethylene) dimethyl ethers.…”

Section: Introductionmentioning

confidence: 99%

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Large Cyclic Poly(oxyethylene)s: Chain Folding in the Crystalline State Studied by Raman Spectroscopy, X-ray Scattering, and Differential Scanning Calorimetry

Cooke

Viras

et al. 1998

Macromolecules

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Crystalline cyclic poly(oxyethylene)s with number-average molar masses (M n) of 4000, 6000, and 10000 g mol -1 were studied by wide-angle (WAXS) and small-angle (SAXS) X-ray scattering, highfrequency and low-frequency laser-Raman spectroscopy, and differential scanning calorimetry (DSC). The subcell of the crystalline cyclic polymers was the same as that of high-molar-mass poly(oxyethylene). Cyclic polymers of Mn ) 4000 or 6000 g mol -1 crystallized in their twice-folded conformation under the conditions investigated, but the cyclic polymer of Mn )10000 g mol -1 crystallized in a four-times-folded conformation when cooled from its melt and in a twice-folded conformation when crystallized slowly at high temperature. Comparison is made with the properties of corresponding linear poly(oxyethylene) dimethyl ethers.

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Section: Methylationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Large Cyclic Poly(oxyethylene)s: Chain Folding in the Crystalline State Studied by Raman Spectroscopy, X-ray Scattering, and Differential Scanning Calorimetry

Cooke

Viras

et al. 1998

Macromolecules

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“…This concept led to research interest in the study of end-group dependence in crystallization and crystal melting behavior of low molecular weight PEO fractions. Booth et al [17][18][19][20] have first investigated low molecular weight PEO fractions with different end groups, including alkoxy'7Ja and acetoxy end gr0ups,~9 Kovacs et al have also reported a PEO fraction with diphenyl and hydroxy end groups. 13 All of these PEO fractions exhibit similar IF crystals grown from the metal.…”

Section: Introductionmentioning

confidence: 99%

Isothermal thickening and thinning processes in low-molecular-weight poly(ethylene oxide) fractions crystallized from the melt. 4. End-group dependence

Cheng¹,

Wu²,

Chen³

et al. 1993

Macromolecules

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A series of low molecular weight poly(ethy1ene oxide) (PEO) fractions with different molecular weights (MW=3000 and7100) andendgroups (-OH,-OCH~,-OC(CH~)S, and-OC&) have beensystematically studied. The end-group effect on diffusional motion in the melt of these PEO fractions was characterized by self-diffusion coefficient measurements through nuclear magnetic resonance. Wide-angle X-ray diffraction experiments indicated that the crystal structures of the PEO fractions with different end groups were identical during and after crystallization. The existence of nonintegral folding chain (NIF) crystals in these PEO fractions in a wide undercooling region was observed by time-resolved synchrotron small-angle X-ray scattering, differential scanning calorimetry, and transmission electron microscopy experiments. The integral folding chain (IF) crystals were found to be formed through both thickening and thinning processes during and/or after the NIF crystallization. It was also found that, with increasing molecular weight and size of the end group, the thickening and thinning processes were increasingly hampered. Of additional interest, the fold length of initial NIF crystals not only increases with crystallization temperature (or decreasing undercooling) for each PEO fraction as commonly observed in polymer lamellar crystals but also changes with the size of the end group. The kinetics of transformation from NIF to IF crystals is explained through the chain sliding diffusional motion along the direction perpendicular to the lamellar surface, which is end-group size dependent. Linear crystal growth rate data measured via polarized light microscopy confirmed that the existence of bulky end groups reduces NIF crystal growth rates for PEO (MW = 3000) fractions. With increasing molecular weight, the end-group dependence gradually vanishes due to the introduction of chain entanglement.

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“…The low-frequency Raman-active longitudinal acoustic vibrational mode (LAM) observed in many semicrystalline polymers has become widely used in studying the structure of such systems. [1][2][3][4][5][6] It has been recognized since the earliest observation of such bands in solid n -p a r a f f i n~~,~ that the mode frequency A i and length L of the sequence undergoing the vibration are related by…”

Section: Introductionmentioning

confidence: 99%

On the use of Raman‐active longitudinal acoustic modes in the study of polyethylene lamellar structures

Glotin

Mandelkern

1983

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

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The first‐, third‐, and fifth‐order low‐frequency, Raman‐active, longitudinal acoustical modes of the n‐alkane C94H190 and different morphological forms of semicrystalline polyethylene have been obtained. An analysis of the results shows that the correction needed to obtain the extended planar‐zigzag ordered sequence length is maximum for the n‐alkane and very small for the polymer systems. These represent solution crystals as well as bulk‐crystallized material. For the latter, samples were prepared so that the crystallite thickness is either comparable to or very much smaller than the extended chain length. An approximate method is also developed which enables the natural linewidth to be determined.

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Raman scattering from the longitudinal acoustic mode in crystalline poly(ethylene oxide)

Cited by 70 publications

References 7 publications

Large Cyclic Poly(oxyethylene)s: Chain Folding in the Crystalline State Studied by Raman Spectroscopy, X-ray Scattering, and Differential Scanning Calorimetry

Large Cyclic Poly(oxyethylene)s: Chain Folding in the Crystalline State Studied by Raman Spectroscopy, X-ray Scattering, and Differential Scanning Calorimetry

Isothermal thickening and thinning processes in low-molecular-weight poly(ethylene oxide) fractions crystallized from the melt. 4. End-group dependence

On the use of Raman‐active longitudinal acoustic modes in the study of polyethylene lamellar structures

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