Chain flexibility and 31P NMR spin lattice relaxation measurements on melts of halogenated poly(thionylphosphazenes)

Raimund Jaeger; Gyula J. Vancso; D. Gates; Y. Ni; I. Manners

doi:10.1021/ma970294h

Chain flexibility and 31P NMR spin lattice relaxation measurements on melts of halogenated poly(thionylphosphazenes)

Raimund Jaeger, Gyula J. Vancso, D. Gates, Y. Ni, I. Manners

Research output: Contribution to journal › Article › Academic › peer-review

3 Citations (Scopus)

Abstract

The chain flexibility of halogenated poly(thionylphosphazenes) (PTPs) [(NSOX) (NPCl2)2]n (X = F, Cl) was investigated by measuring the 31 P spin−lattice relaxation times of PTP melts. T1 times were obtained at two different magnetic fields and at various temperatures above the glass transition of the polymers. The minimal T1 time occurred at lower temperatures for the fluorinated polymer than for the chlorinated polymer. This result is in agreement with trends in glass transition temperatures of these polymers and with ab initio molecular orbital calculations on the chain flexibility of model compounds of these polymers. The Hall−Helfand model for the dynamics of polymer chains was used to fit the experimental T1(T) curves. This model describes the motions of the polymer chains that lead to the longitudinal relaxation as correlated conformational jumps. T1 measurements at two different field strengths indicated that chemical shift anisotropy contributes significantly to the spin−lattice relaxation.

Original language	English
Pages (from-to)	6869-6872
Journal	Macromolecules
Volume	30
Issue number	22
DOIs	https://doi.org/10.1021/ma970294h
Publication status	Published - 1997

Keywords

IR-82914
METIS-105730

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10.1021/ma970294h

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title = "Chain flexibility and 31P NMR spin lattice relaxation measurements on melts of halogenated poly(thionylphosphazenes)",

abstract = "The chain flexibility of halogenated poly(thionylphosphazenes) (PTPs) [(NSOX) (NPCl2)2]n (X = F, Cl) was investigated by measuring the 31 P spin−lattice relaxation times of PTP melts. T1 times were obtained at two different magnetic fields and at various temperatures above the glass transition of the polymers. The minimal T1 time occurred at lower temperatures for the fluorinated polymer than for the chlorinated polymer. This result is in agreement with trends in glass transition temperatures of these polymers and with ab initio molecular orbital calculations on the chain flexibility of model compounds of these polymers. The Hall−Helfand model for the dynamics of polymer chains was used to fit the experimental T1(T) curves. This model describes the motions of the polymer chains that lead to the longitudinal relaxation as correlated conformational jumps. T1 measurements at two different field strengths indicated that chemical shift anisotropy contributes significantly to the spin−lattice relaxation.",

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year = "1997",

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T1 - Chain flexibility and 31P NMR spin lattice relaxation measurements on melts of halogenated poly(thionylphosphazenes)

AU - Jaeger, Raimund

AU - Vancso, Gyula J.

AU - Gates, D.

AU - Ni, Y.

AU - Manners, I.

PY - 1997

Y1 - 1997

N2 - The chain flexibility of halogenated poly(thionylphosphazenes) (PTPs) [(NSOX) (NPCl2)2]n (X = F, Cl) was investigated by measuring the 31 P spin−lattice relaxation times of PTP melts. T1 times were obtained at two different magnetic fields and at various temperatures above the glass transition of the polymers. The minimal T1 time occurred at lower temperatures for the fluorinated polymer than for the chlorinated polymer. This result is in agreement with trends in glass transition temperatures of these polymers and with ab initio molecular orbital calculations on the chain flexibility of model compounds of these polymers. The Hall−Helfand model for the dynamics of polymer chains was used to fit the experimental T1(T) curves. This model describes the motions of the polymer chains that lead to the longitudinal relaxation as correlated conformational jumps. T1 measurements at two different field strengths indicated that chemical shift anisotropy contributes significantly to the spin−lattice relaxation.

AB - The chain flexibility of halogenated poly(thionylphosphazenes) (PTPs) [(NSOX) (NPCl2)2]n (X = F, Cl) was investigated by measuring the 31 P spin−lattice relaxation times of PTP melts. T1 times were obtained at two different magnetic fields and at various temperatures above the glass transition of the polymers. The minimal T1 time occurred at lower temperatures for the fluorinated polymer than for the chlorinated polymer. This result is in agreement with trends in glass transition temperatures of these polymers and with ab initio molecular orbital calculations on the chain flexibility of model compounds of these polymers. The Hall−Helfand model for the dynamics of polymer chains was used to fit the experimental T1(T) curves. This model describes the motions of the polymer chains that lead to the longitudinal relaxation as correlated conformational jumps. T1 measurements at two different field strengths indicated that chemical shift anisotropy contributes significantly to the spin−lattice relaxation.

KW - IR-82914

KW - METIS-105730

U2 - 10.1021/ma970294h

DO - 10.1021/ma970294h

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VL - 30

SP - 6869

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JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

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