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Investigation of the Temperature Dependence of Free Volume in Polymethylpentene by Positron Annihilation Method

100%

Danch A., Osoba W.

Acta Physica Polonica A

2005

vol. 107

issue 5

811-816

Positron lifetime measurements in polymethylpentene were performed in a wide temperature range. A conventional fast-slow coincidence lifetime spectrometer with plastic scintillators was used. All the measurements were made in vacuum. Additional measurements (X-ray diffraction, differential scanning calorimetry, and mechanical spectroscopy) were also performed to establish properties of samples. Mean free volume radii in the investigated samples were estimated from the positron lifetimes measurements results. An increase in I_3 with the elapsed time of measurements was observed.

Influence of Temperature and Pressure on the Free Volume in Thermo-Shrunken Polyethylene by Positron Annihilation

81%

Danch A., Osoba W., Wawryszczuk J.

Acta Physica Polonica A

2008

vol. 113

issue 5

1307-1313

Positron lifetime measurements were performed as a function of temperature and pressure for thermo-shrunken polyethylene. Mean volume of free volume cavities in the investigated polymer was estimated from the results of the measurements. This mean volume turned out to be the smooth function of temperature (from room temperature to 8.5 K) and high pressure (from 0.1 MPa to about 500 MPa). The effect of trapping of the free electrons produced during positron irradiation was observed at low temperature.

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2 Acta Physica Polonica A

1 2008

1 2005

2 Danch A.

2 Osoba W.

1 Wawryszczuk J.

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Investigation of the Temperature Dependence of Free Volume in Polymethylpentene by Positron Annihilation Method

Influence of Temperature and Pressure on the Free Volume in Thermo-Shrunken Polyethylene by Positron Annihilation