1994 Volume 29 Issue 9 Pages 477-481
The evaluation of unoccupied space in epoxies has been evaluated in terms of positron annihilation method. Based on the evaluated unoccupied space the cohesive condition of the epoxy molecular was modeled. The model suggested that the epoxies were classified into two types that is the epoxy could be explain by the free volume and that by free space. The former was understood as the epoxy of which molecular network was destroyed by the plasticizer and the latter as that of which molecular weight between crosslinks was changed. In this work the former mechanism was confirmed experimentally. The addition of plasticizer was confirmed not to be effective to improve the cryogenic mechanical properties as expected by the model.
