Investigation of foamed polystyrene by positron annihilation lifetime
spectroscopy
Chem.
Met. Alloys 4
(2011) 81-84
https://doi.org/10.30970/cma4.0166
Marek KOSTRZEWA, Adam INGRAM, Sylwester
WACKE
Positron annihilation lifetime
measurements obtained for foamed polystyrene samples of different density are
presented. Two series of samples (exposed and not exposed to open air) were
investigated. The dimensions of the pores were determined. The free volume was
found to decrease from 137 to 104 Å3 with increasing density
of the material. The largest concentration of micropores
(dimensions up to ~0.7 nm), represented by the intensity of the long-lived
component, was obtained for a solid (not foamed) sample.
Upper panel: delayed-coincidence
spectrum obtained for solid polystyrene (HDPS). The
result of the deconvolution of the spectrum into
contributions of individual positron fractions to the annihilation process is
shown. Lower panel: difference between the experimental spectrum and its fit
expressed in units of standard deviation.
Keywords
Foamed polystyrene / Positron
annihilation / Micropores