Synergistic effect of EVA-GMA and nanofillers on mechanical and dielectric properties of polyamide

Hydroxylated BaTiO 3 (BT-OH) and multiwalled carbon nanotubes (MWCNTs) were incorporated into polyamide (PA) and ethylene-vinyl-acetate-glycidyl methacrylate random terpolymer (EVA-GMA) blends by melting-blend and hot-pressing method. Compared with PA/EVA-GMA/C nanocomposites, PA/EVA-GMA/20B/C nanocomposites exhibited higher dielectric permittivity, originating from the high dielectric constant of BT-OH and remarkable interface polarization effect between polymer and two types of nanofillers. Moreover, the nonconducting BT-OH can prevent the conductive path of MWCNTs and support low loss tangent. The dielectric constant of PA/EVA-GMA/20B/4C was 31.5 at 100 Hz, approximately three times higher than that of PA/EVA-GMA, and the loss factor was only 0.18, close to that of PA/EVA-GMA. PA/EVA-GMA/20B/4C exhibited tensile strength and elongation at break of 27.7 MPa and 67.9%, respectively. The mechanical and dielectric properties of PA/EVA-GMA/20B/4C were synergistically improved.