- Tytuł:
- Positron Annilation Lifetime and Glass Transition Temperatures in $CO_2$ Sorption Polystyrene
- Autorzy:
-
Jean, Y.
Chen, H.
Lee, L.
Yang, J. - Powiązania:
- https://bibliotekanauki.pl/articles/1812530.pdf
- Data publikacji:
- 2008-05
- Wydawca:
- Polska Akademia Nauk. Instytut Fizyki PAN
- Tematy:
-
78.70.Bj
78.66.Qn
71.60.+z - Opis:
- Positron annihilation lifetime spectroscopy was used to measure the free-volume size and distributions as a function of temperature in polystyrene with and without 400 psi $CO_2$ sorption. The transition temperatures in the polystyrene with $CO_2$ sorption obtained from ortho-positronium lifetimes were found to depend on the thermal cycles and a meta-stable state showing a negative thermal expansion coefficient was observed between 53°C and 82°C during the first heating up experiment. The observed $T_g$ in polystyrene with, and without $CO_2$ sorption after annealing from ortho-positronium lifetimes were found to be 86°C and 91°C, which are 5°C higher, and 10°C lower than from the differential scanning calorimetry data, respectively. The observed free-volume variations are discussed in terms of hole expansion, creation, free-volume relaxation, plasticization, and hole filling in amorphous polymers.
- Źródło:
-
Acta Physica Polonica A; 2008, 113, 5; 1385-1395
0587-4246
1898-794X - Pojawia się w:
- Acta Physica Polonica A
- Dostawca treści:
- Biblioteka Nauki
Artykuł