PALS free volume study of dry and water saturated epoxies

Flee volume cavity sizes and fractions of epoxy specimens were determined using positron annihilation lifetime spectroscopy (PALS). PALS data were obtained before and after specimen water equilibration, Specimens were bisphenol A epoxide (B) and/or glycol epoxide (G) cured with a polyomide. Free volume sites increased linearly and cavity sizes decreased linearly with epoxide B:G ratio. Glass transition temperature (T-g) increased with epoxide B:G ratio. Water molecules in wet epoxy B filled approximately six percent of the cavities. epoxy G cavity size increased 11.4% after water equilibrium and was ascribed to cavity expansion-PALS results differed for commercial corrosion inhibitors in wet and dry mixtures of these epoxides.