Deuteron NMR relaxation and molecular motion of polystyrene in solution

Grandjean, Jean; Sillescu, H.; Willenberg, B.

doi:10.1002/macp.1977.021780519

Cited by 21 publications

(7 citation statements)

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“…A reanalysis of their data using eq 5 with α = 0.76 gives an activation energy of 13 kJ/mol in toluene and 18 kJ/mol in cyclohexane. Grandjean et al performed 2 H T 1 experiments on 16% and 18% PS- d 3 in benzene and in diethyl malonate, respectively. They used Kramers' theory to obtain activation energies of 14 kJ/mol in benzene and 12 kJ/mol in diethyl malonate.…”

Section: Resultsmentioning

confidence: 99%

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Viscosity Dependence of Polystyrene Local Dynamics in Dilute Solution

Zhu

Ediger

1997

Macromolecules

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Variable-temperature 2H NMR T 1 measurements have been performed on backbone-deuterated atactic polystyrene at two Larmor frequencies in four solvents: toluene, cis-decalin, dibutyl phthalate, and dioctyl phthalate. The time integral 〈σ〉 of the C−D vector orientation correlation function is extracted from the T 1 data without assuming a specific model for C−D vector reorientation. The hydrodynamic Kramers' theory in the high-friction limit cannot describe the viscosity and temperature dependence of 〈σ〉. In contrast, 〈σ〉 is found to have a power law dependence on solvent viscosity with an exponent of 0.76 ± 0.05, whether the viscosity is varied by changing solvent or temperature. The internal energy barrier for polystyrene C−D vector orientation is determined to be 14 ± 3 kJ/mol using the power law viscosity dependence. The inapplicability of Kramers' theory is attributed to the lack of a clear separation between the time scales of polymer and solvent motions. As expected on the basis of this explanation, the viscosity exponents for polystyrene and five other polymers are found to correlate with the molecular weight of the side groups.

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Section: Resultsmentioning

confidence: 99%

“…All these results are in reasonably agreement with those reported here. In the work reported in refs and , specific models were employed to fit the data. It is not known whether other models would give the same results.…”

Section: Resultsmentioning

confidence: 99%

Viscosity Dependence of Polystyrene Local Dynamics in Dilute Solution

Zhu

Ediger

1997

Macromolecules

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“…The quadrupole coupling constant of the CD bond was chosen to be 170 ± 5 kHz. 34 A weighted least-squares algorithm35 was used in fitting the theoretical spectral density functions (eq 3 The spectral density function eq 3 was fitted to the spectral density values of Table II. The high-frequency parameter is related to the fast motions.…”

Section: Resultsmentioning

confidence: 99%

Main-chain dynamics of sodium poly(acrylate) as probed by NMR: a comparison of models

Rijn¹,

Bleijser²,

Leyte³

1987

Macromolecules

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“…TIP' appears to involve only a short section of the PS chain: according to IR, it corresponds to breakup of 31 helices in PS [go], Tpp' has been observed by DSC in some other polymers selected because of bulky side groups [89]. It is not clear to us at this time whether the T > T event seen in PS by NMR, using the partial deuteration technique of Sillescu et al [92,93] is TpP o r TPP '. The final point in discussing Fig.…”

Section: H I S T O R I C a L P E R S P E C T I V E O N T H E L I Q U mentioning

confidence: 97%

Dynamics and thermodynamics of the liquid state (T < T_g) of amorphous polymers

Boyer

1980

Journal of Macromolecular Science, Part B

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A B S T R A C TThe liquid state behavior of the following atactic polymers has been reviewed: the alkyl and cycloalkyl methacrylates; polyisobutylene; polybutadiene, its random copolymers with styrene and acrylonitrile, and S-B diblocks; polystyrene; and the poly-cuolefins C3, C5, and C Just as T manifests itself through time-dependent (relaxational) and thermodynamic (transition) effects, so also does a T > T transition (relaxation) found generally in the range of 1.1 t o 1.3 T but mostly near 1 . 2 T This is designated as TQQ, a liquidl-liquid transition. T a~ is found, usually by a variety of dynamic, thermodynamic, and probe methods, in all of the above classes of polymers plus iso-PMMA, which also has a weak T < T o r T relaxation. With increasing syndiotactic content, PMMA's reveal strengthening T and T processes. Relaxation maps plotting log frequency-T TQQ. tion enthalpy about half that at T when both are observed some 50-100°K above their very low frequency values. Probe methods 6' g g g g' 2 g P P QQ-1 a r e presented for PBD and PIB, showing both T and g The latter exhibits non-Arrhenius behavior with an activag 461 Copyright 0 198 1 by Marcel Dekker, Inc. Downloaded by [Tulane University] at 09:04 05 January 2015 462 BOYER such as IR, "C-NMR, ESR with spin probes, depolarization of fluorescence, and thermally stimulated current seem unusually well suited to studies of the liquid state. The earliest concept of a TPL is that of Ueberreiter in 1943; the earliest experimental evidence is the torsion pendulum data of Schmieder and Wolf on PIB in 1953 and PMMA in 1957. TLP is inherently weak comparedto T and its strength is polymer specific, being relatively strong in PIB, weak in PBD. TLp is compared with the "slow process"of F e r r y and co-workers, ascribed t o slippage of dangling entanglements. TPQ occurs also below the entanglement molecular weightMc.Modern statistical methods such a s regression analysis are used to analyze T > T data for the presence o r absence of weak transitions, especially V-T and C -T data. The possibility of artifacts in some methods makes it imperative to search for T P p by many alternate methods, It is shown that isothermal V -P plots are more revelatory of TLL than a r e isobaric V-T plots. The use of Wood's variation of the Tait equation relating bulk modulus and pressure is useful in some cases for locating liquid state relaxations. Preliminary estimates of d(TQP)/dP, presented for PnBMA, P(cyclohexy1 MA) and a-PS, a r e in the range of 50-70 K/kbar, i.e. , 2-3 times the well known values for dT dP. A phase dualism hypothesis by Frenkel and Baranov suggests that TPL represents competition between segment-segment (liquid-like) behavior and the tendency of the macromolecule t o act as a gas at high temperature, Melt elasticity measurements on PS reveals a molecular weight dependent transition which appears to be TPQ ,The enthalpy of activation decreases by a factor of two from below to above TPp. The term "thermodynamic" in the title signifies use of quasi-equilibrium typ...

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Deuteron NMR relaxation and molecular motion of polystyrene in solution

Cited by 21 publications

References 23 publications

Viscosity Dependence of Polystyrene Local Dynamics in Dilute Solution

Viscosity Dependence of Polystyrene Local Dynamics in Dilute Solution

Main-chain dynamics of sodium poly(acrylate) as probed by NMR: a comparison of models

Dynamics and thermodynamics of the liquid state (T < T_g) of amorphous polymers

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Deuteron NMR relaxation and molecular motion of polystyrene in solution

Cited by 21 publications

References 23 publications

Viscosity Dependence of Polystyrene Local Dynamics in Dilute Solution

Viscosity Dependence of Polystyrene Local Dynamics in Dilute Solution

Main-chain dynamics of sodium poly(acrylate) as probed by NMR: a comparison of models

Dynamics and thermodynamics of the liquid state (T < Tg) of amorphous polymers

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Product

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Dynamics and thermodynamics of the liquid state (T < T_g) of amorphous polymers