T. Okada et al., PHYSICAL-PROPERTIES OF EPOXY AND FREE-VOLUME EVALUATED BY POSITRON-ANNIHILATION SPECTROSCOPY, Journal de physique. IV, 3(C4), 1993, pp. 291-294
The macroscopic physical properties of commercially available bispheno
l -A epoxy resins cured by acid anhydride in which amount of the plast
icizer, polypropyleneglycol was changed systematically have been measu
red and were compared with the amount of free volume evaluated by the
positron annihilation technique. The lifetime and the intensity of ort
hopositronium were used to evaluate the amount of the free volume in t
he epoxy resins. It was found that up to the certain amount of plastic
izer, the amount of the free volume did not increase so much and then
showed the marked increase. The close correlations were found between
the amount of the free volume and the macroscopic physical properties
such as hardness and specific volume.