Abstract
Temperature dependence of the lifetime {tau}3 and intensity I{sub 3} of the long-lived ortho-positronium (o-Ps) component was measured for two polyimides PI189 and PI304 both below and above glass-transition temperatures Tg of these polymers. First heating runs of the experiments revealed anomalous, irregular behavior of the lifetime {tau}3 in both PI in the vicinity (below) of the glass transition temperature. The effect was similar to that discussed recently for a number of PI. However, on the cooling stage of the first cycle and on the heating run of the second cycle, such irregularities disappeared. These results show that anomalous behavior of annihilation characteristics of o-Ps in our PI samples were due not to anomalous behavior of PI structure itself close to Tg point (not to a specific phase transition), but to removal of residual solvent in vicinity of Tg during the first heating cycle. Different approaches to estimations of the specific hole volume and of the holes number density N on the basis of positron annihilation data are discussed. Final estimation for PI189 gives the fractional free volume h=3.35% and N=0.44x1027m-3. The effects of positron trapping by polar-CO groups on annihilation characteristics of PI and on the obtained value of
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Shantarovich, V P;
[1]
Suzuki, T;
[2]
He, C;
[2]
Ito, Y;
[3]
Yampolskii, Y P;
[4]
Alentiev, A Yu
[4]
- N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul Kosygina 4 st., 119334 Moscow (Russian Federation)
- High Energy Accelerator Research Organization KEK, Tsukuba 305-0801 (Japan)
- Reasearch Center for Nuclear Science and Technology, The University of Tokyo, Tokai, Ibaraki 319-1106 (Japan)
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29 Leninskii Pr., 117912 Moscow (Russian Federation)
Citation Formats
Shantarovich, V P, Suzuki, T, He, C, Ito, Y, Yampolskii, Y P, and Alentiev, A Yu.
Positron annihilation in PI189 and PI304 polyimides.
United Kingdom: N. p.,
2005.
Web.
doi:10.1016/j.radphyschem.2004.06.005.
Shantarovich, V P, Suzuki, T, He, C, Ito, Y, Yampolskii, Y P, & Alentiev, A Yu.
Positron annihilation in PI189 and PI304 polyimides.
United Kingdom.
https://doi.org/10.1016/j.radphyschem.2004.06.005
Shantarovich, V P, Suzuki, T, He, C, Ito, Y, Yampolskii, Y P, and Alentiev, A Yu.
2005.
"Positron annihilation in PI189 and PI304 polyimides."
United Kingdom.
https://doi.org/10.1016/j.radphyschem.2004.06.005.
@misc{etde_20620274,
title = {Positron annihilation in PI189 and PI304 polyimides}
author = {Shantarovich, V P, Suzuki, T, He, C, Ito, Y, Yampolskii, Y P, and Alentiev, A Yu}
abstractNote = {Temperature dependence of the lifetime {tau}3 and intensity I{sub 3} of the long-lived ortho-positronium (o-Ps) component was measured for two polyimides PI189 and PI304 both below and above glass-transition temperatures Tg of these polymers. First heating runs of the experiments revealed anomalous, irregular behavior of the lifetime {tau}3 in both PI in the vicinity (below) of the glass transition temperature. The effect was similar to that discussed recently for a number of PI. However, on the cooling stage of the first cycle and on the heating run of the second cycle, such irregularities disappeared. These results show that anomalous behavior of annihilation characteristics of o-Ps in our PI samples were due not to anomalous behavior of PI structure itself close to Tg point (not to a specific phase transition), but to removal of residual solvent in vicinity of Tg during the first heating cycle. Different approaches to estimations of the specific hole volume and of the holes number density N on the basis of positron annihilation data are discussed. Final estimation for PI189 gives the fractional free volume h=3.35% and N=0.44x1027m-3. The effects of positron trapping by polar-CO groups on annihilation characteristics of PI and on the obtained value of N are also considered.}
doi = {10.1016/j.radphyschem.2004.06.005}
journal = []
issue = {1}
volume = {73}
journal type = {AC}
place = {United Kingdom}
year = {2005}
month = {May}
}
title = {Positron annihilation in PI189 and PI304 polyimides}
author = {Shantarovich, V P, Suzuki, T, He, C, Ito, Y, Yampolskii, Y P, and Alentiev, A Yu}
abstractNote = {Temperature dependence of the lifetime {tau}3 and intensity I{sub 3} of the long-lived ortho-positronium (o-Ps) component was measured for two polyimides PI189 and PI304 both below and above glass-transition temperatures Tg of these polymers. First heating runs of the experiments revealed anomalous, irregular behavior of the lifetime {tau}3 in both PI in the vicinity (below) of the glass transition temperature. The effect was similar to that discussed recently for a number of PI. However, on the cooling stage of the first cycle and on the heating run of the second cycle, such irregularities disappeared. These results show that anomalous behavior of annihilation characteristics of o-Ps in our PI samples were due not to anomalous behavior of PI structure itself close to Tg point (not to a specific phase transition), but to removal of residual solvent in vicinity of Tg during the first heating cycle. Different approaches to estimations of the specific hole volume and of the holes number density N on the basis of positron annihilation data are discussed. Final estimation for PI189 gives the fractional free volume h=3.35% and N=0.44x1027m-3. The effects of positron trapping by polar-CO groups on annihilation characteristics of PI and on the obtained value of N are also considered.}
doi = {10.1016/j.radphyschem.2004.06.005}
journal = []
issue = {1}
volume = {73}
journal type = {AC}
place = {United Kingdom}
year = {2005}
month = {May}
}