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ELECTRON
-
PARAMAGNETIC RESONANCE APPLICATION

TO POLYMERS .4. THE

SEGMENTAL VOLUME OF POLY(PHENYLACETYLENE)

USING DIFFERENT NITROXIDE

SPIN PROBES

HWANG, JS; SALEEM, MM; TSONIS, CP

ELSEVIER SCI LTD, POLYMER; pp: 231
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234; Vol: 32

King Fahd University of Petroleum & Minerals

http://www.kfupm.edu.sa

Summary

Electron paramagnetic resonance (e.p.r.) studies of T(50G) of poly(phenylacetylene)

have been carried out at X
-
band as a function of spin probe size over a wide range of

temperatures.It was found that T(50G) increased with increasing probe size.The

polymer glass transition temperature T(g), determined from the break on the plot of ln

T(R) versus 1/T for tempone in poly(phenylacetylene), was 296 K.The apparent

activation enthalpy for the T(g) relaxation process increased with increasing probe

size, while the segmental size of the polymer appeared to be independent of the

nitroxide used, and has a range of 898
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922 angstrom 3.The segmental volume

measured by the spin probe technique is in excellent agreement with the volume of

970 angstrom 3 of 10 repeat units on an average chain based on number
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average

molecular weight of 960.Thus our results showed that there are 17
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20 backbone atoms

in the segment of poly(phenylacetylene).Assuming the polymer segment to be of

spherical shape, the diameter of the sphere was found to have a range of 11.7
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12.4

angstrom.

References:

BOYER RF, 1977, MACROMOLECULES, V9, P461

GOLDMAN SA, 1972, J PHYS CHEM
-
US, V76, P1858

HWANG JS, 1983, MACROMOLECULES, V16, P736

Copyright: King Fahd University of Petroleum & Minerals;

http://www.kfupm.edu.sa

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HWANG JS, 1985, MACROMOLECULES, V18, P2051

KUMLER PL, 1976, MACROMOLECULES, V9, P903

KUSUMOTO N, 1976, POLYMER, V17, P448

KUSUMOTO N, 1977, REG PROG POLYM PHYS, V22, P519

For pre
-
prints please write to:
abstracts@kfupm.edu.sa

Copyright: King Fahd University of Petroleum & Minerals;

http://www.kfupm.edu.sa