View More View Less
  • 1 University of Wrocŀaw Institute of Experimental Physics Maxa Borna 9 50-204 Wrocŀaw (Poland)
  • 2 Institute of Coal Chemistry PAN Sowińskiego 62 44-100 Gliwice (Poland)
Restricted access


Positron annihilation has been applied to study samples of two crosslinked epoxy resins: onglycidyl ether of bisphenol A (Epikote 828) and polyglycidyl-ether of phenol-formaldehyde novolac (Epikote 155) cured with 4,4

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$I_3 \cdot \bar v$$ \end{document}
, proportional to the fractional free volume in samples. Values of
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\bar v$$ \end{document}
have been estimated from the values of 3, the longest lifetime in positron lifetime spectra.I3 corresponds to the intensity of the longest-lived component in them. Distributions of free volume radii reconstructed on the basis of PAL measurements are given for all samples. The influence of structure of both cured resin and the curing agent on the properties of the crosslinked products is clearly seen from the presented results.