Interface modified BTO@PS--mah/PS composite dielectrics with enhanced breakdown strength and ultralow dielectric loss.

Dielectrics of the polymer-matrix composite are considered to present combined advantages from both the polymer matrix and inorganic fillers. However, the breakdown strength, as well as energy density, is not effectively enhanced due to the poor compatibility between the organic and inorganic components. Herein, polymer composites derived from polystyrene (PS) and barium titanate (BTO) are proposed and beneficial interface modification by poly(styrene--maleic anhydride) (PS--mah) is conducted to improve compatibility between the inorganic filler and polymer matrix. The results show that the BTO@PS--mah/PS composites, in which the interfacial layer of PS--mah would undergo chemical reactions with the aminated BTO and blend PS matrix with excellent physical compatibility, exhibit enhanced breakdown strength and declined dielectric loss compared with both pure PS and BTO/PS without interfacial modulation. Particularly, the BTO@PS--mah/PS composite with 5 wt% filler content indicates optimized performance with an of 507 MV m and tan  of 0.085%. It is deduced that the deep energy traps introduced by the PS--mah layer would weaken the local electric field and suppress the space charge transporting so as to optimize the performance of composites. Consequently, the interfacial-modified BTO@PS--mah/PS would present great potential for applications, such as film capacitors.