The calorimetric curves and the dielectric relaxation spectra corresponding to blends of diglycidyl ether of bisfenol-A with different concentration of poly(ethylene-co-vinyl acetate)-g-poly(methyl methacrylate) (EVA-g-PMMA) were obtained using differential scanning calorimetry (DSC) and dielectric relaxation espectroscopy (DSR), respectively. The glass transition temperature (Tg) of the PMMA segment of increases with the copolymer content in the blends. The Tg behavior was described by the Gordon-Taylor equation, using the weight fraction of PMMA. In the dielectric relaxation spectrum, α relaxations of the two molecular segments are deserved. In this case, the increase in copolymer concentration led to the increase of α -relaxation corresponding to the PMMA segment, and there was not change in α -relaxation for the EVA fraction. These behaviors show that the structural segments have very different interactions with the epoxy monomer. The PMMA segment of is miscible in the epoxy resin, therefore, provoked strong interactions with the resin when compared to EVA fraction, which presented no apparent interaction and gave origin to the system heterogenity.
Miscibility; diglycidyl ether of bisphenol-A; grafting copolymer; differential scanning calorimetry; dielectric spectrum
