Dielectric relaxations in polymers with pendent phenyl or pyridine groups at temperatures from 4°K to 80°K

Shimizu, Kayoko; Yano, Okihito; Wada, Yasaku

doi:10.1002/pol.1975.180131210

Cited by 23 publications

(17 citation statements)

References 19 publications

(2 reference statements)

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“…For PiPMA, the rotation of the ester isopropyl group (␦-relaxation in PiPMA) around the COO bond was reported around 50 K as a loss shoulder in a dielectric relaxation measurement (320 Hz-10 kHz). 25 For PnPMA, the rotation of the terminal ethyl group around the COC bond was reported at 90 K in a mechanical relaxation measurement (below 0.5 Hz). 16 The continuous increase in hole width for PiPMA and PnPMA in Figure 8 can be attributed to these rotations.…”

Section: Temperature Dependence Of Final Cis Fraction Compared With Tmentioning

confidence: 99%

Local free volume and structural relaxation studied with photoisomerization of azobenzene and persistent spectral hole burning in poly(alkyl methacrylate)s at low temperatures

Yoshii

Machida

Horie

2000

J. Polym. Sci. B Polym. Phys.

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Section: Temperature Dependence Of Final Cis Fraction Compared With Tmentioning

confidence: 99%

Local free volume and structural relaxation studied with photoisomerization of azobenzene and persistent spectral hole burning in poly(alkyl methacrylate)s at low temperatures

Yoshii

Machida

Horie

2000

J. Polym. Sci. B Polym. Phys.

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“…Such lowering of the dispersion temperature of dispersion II by racemic mixing has been also reported for PBDG + PBLG. 30 In Figure 9 is shown the temperature dependence C!f the relaxation strength obtained by the Cole-Cole plot.…”

Section: P-npbdg P-cipbdg and P-mepbdgmentioning

confidence: 99%

Molecular Motions of Poly(γ-monosubstituted-benzyl D-glutamate) in the Solid State

Sasaki

Tsutsumi

Hikichi

et al. 1979

Polym J

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ABSTRACT:Dielectric measurements were performed at frequencies ranging from 30Hz to 300KHz and at temperatures between -150 and l20°C for the following poly(y-monosubstitutedbenzyl n-glutamate)s; poly(y-o-chlorobenzyl o-glutamate) (o-CIPBDG), poly(y-m-chlorobenzyl Dglutamate) (m-CIPBMDG), poly(y-p-chlorobenzyl D-glutamate) (p-CIPBDG), poly(y-p-nitrobenzyl o-glutamate) (p-NPBDG), poly(y-p-methylbenzyl o-glutamate) (pMePBDG) and a racemic mixture of p-CIPBDG and p-CIPBLG (p-CIPBDG+p-CIBLG). Each sample exhibited a dielectric loss maximum in the temperature range of These loss maxima were attributed to the onset of large scale motion of side chains. The temperatures of maximum loss (the dispersion temperature) are shifted by the introduction of substituents. The dispersion temperature is highest for p-CIPBDG among three monochlorosubstituted PBDGs. For p-monosubstituted-PBDGs, p-NPBDG, which has the side chain with the largest dipole moment among three p-substituents studied, showee the highest dispersion temperature. The results are explained in terms of restriction caused by dipole-dipole interaction among dipoles in the side chain. The enormous relaxation strength of o-CIPBDG was considered to reflect a certain conformation of the side chain originating from steric hindrance between the ester and the a-substituent of a side chain. Racemic mixtures of p-CIPBDG and p-CIPBLG showed no evidence of the first-order solid-solid transition observed for racemic mixtures of PBDG and PBLG.KEY WORDS Poly(y-monosubstituted-benzyl n-glutamate) I Side-ChainMotion I Dipole-Dipole Interaction I Steric Hindrance I Racemic Mixtures I It has widely been accepted that even in the solid state, long side chains of the ()(-helical poly(IJ(-amino acid) undergo considerable motions while ()(-helical main chain remains rigid. The importance of side-chain motions of the ()(-helical poly(1J(-amino acid) in determining properties in the solid state has been recognized. 1 -9 conformation of the ()(-helical backbone. 13 • 14 Though qualitatively, the dependence of the helical structure and its stability on the species of the side chain has been explained in terms of side chain-side chain and side chain-backbone interactions. 8 Recently, it has been reported that in a series of poly(y-monosubstituted-benzyl o-glutamate)s, in which a substituent is introduced into the phenyl ring at the end of the side chain of poly(y-benzyl oglutamate) (PBDG), the properties markedly depend on the species and the position of the substituent.10 -12 It has been also reported that the different position of the substitution affects the * 3 To whom all inquiries should be addressed.The purpose of the present investigation is to examine the effects of the substitution to the benzyl group of PBDG on side-chain motions of PBDG. Dielectric and broad-line nuclear magnetic resonance measurements were performed to observed molecular motions for the following seven samples of poly(y-monosubstituted -benzyl glutamate)s; poly(y--chlorobenzyl o-glutamate) (o-ClPBDG), poly(y...

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“…It is reasonable to assume that this is caused by a molecular motion originating in the alkyl side chain, similar to that observed in poly-(alkyl methacrylates) (15,16). The movement will entail either simple rotation about -(C-C)-bonds of the type suggested by Shimizu et alia (17) and outlined in Figure 3 …”

Section: Poly(mono-n-alkyl Itaconic Acid Esters)mentioning

confidence: 99%

Physical properties of polymers based on itaconic acid

Cowie¹

1979

Pure and Applied Chemistry

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Dielectric relaxations in polymers with pendent phenyl or pyridine groups at temperatures from 4°K to 80°K

Cited by 23 publications

References 19 publications

Local free volume and structural relaxation studied with photoisomerization of azobenzene and persistent spectral hole burning in poly(alkyl methacrylate)s at low temperatures

Local free volume and structural relaxation studied with photoisomerization of azobenzene and persistent spectral hole burning in poly(alkyl methacrylate)s at low temperatures

Molecular Motions of Poly(γ-monosubstituted-benzyl D-glutamate) in the Solid State

Physical properties of polymers based on itaconic acid

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