ELECTRON IRRADIATED EFFECT IN POLYURETHANES STUDIED BY POSITRON ANNIHILATION LIFETIME SPECTROSCOPY

Farzana  Nahid

doi:10.53808/KUS.2010.10.1and2.0914-E

Authors

Farzana Nahid Forestry and Wood Technology Discipline, Khulna University, Khulna 9208, Bangladesh

DOI:

https://doi.org/10.53808/KUS.2010.10.1and2.0914-E

Keywords:

Positron annihilation, positronium lifetime, ortho-positronium, trapped electrons, free volume

Abstract

The intensity variation of positronium as a result of electron irradiation has been studied on polyurethanes (PU) using positron annihilation lifetime spectroscopy (PALS). The PALS measurement was carried out at room temperature with a conventional fast-fast coincidence system. The lifetime spectra were analyzed into four components using melt program to extract the positron parameters such as lifetime and intensity. Due to irradiation a decrease of intensity about 2.7% was observed up to 10kGy. Free volume radius has been calculated for electron irradiated PU. PALS measurement has also been performed to study the effect of temperature variation in the range 30K to 310K. Analysis by melt program on the spectra shows that the fourth lifetime component increases significantly above glass transition temperature.

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