Mechanical properties and morphology of epoxy/poly(vinyl acetate)/poly(4-vinyl phenol) brominated system

Diglycidyl ether of bisfenol-A (DGEBA)/poly(vinyl acetate) (PVAc)/poly(4-vinyl phenol) brominated (PVPhBr) ternary blends cured with 4,4'-diaminodiphenylmethane (DDM) were investigated by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM). Homogeneous (DGEBA+DDM)/PVPhBr networks with a unique T-g are generated. Ternary blends (DGEBA+DDM)/PVAc/PVPhBr are initially miscible and phase separate upon curing arising two T(g)s that correspond to a PVAc-rich phase and to epoxy network phase. Increasing the PVPhBr content the T-g of the PVAc phase move to higher temperatures as a consequence of the PVAc-PVPhBr interactions. Different morphologies are generated as a function of the blend composition.