Investigation of interfacial interaction and structural transition for epoxy/nanotube composites by positron annihilation lifetime spectroscopy

Positron annihilation lifetime spectroscopy was employed to study the effect of amine modification on interfacial interaction and structural transition for epoxy/multiwalled carbon nanotube (MWNT) composites. Temperature dependence of orthopositronium lifetimes suggests that sample with amine-modified MWNTs possesses the highest glass transition temperature compared with unmodified samples and neat epoxy resin, which indicates that stronger interfacial interactions exist between epoxy matrix and amine-modified MWNTs, as a result of the covalent bonds and other weak forces. This is testified by interaction parameter beta calculated in terms of the positron annihilation parameter.