Effects of B2O3 addition on structural and dielectric properties of PVDF



α-Crystalline form of PVDF doped with Boron oxide (B2O3) composite films were produced between 0.2 and 1% weight ratio via the casting procedure. This low-level doping rate did not change the crystalline structure of PVDF; however, they increased the lower and upper glass transition temperatures, which are associated with the amorphous ratio of polymer. This increment was found to be the highest for the sample 0.8% B2O3-doped PVDF as 25 and 9.7%, respectively. Because of the low specific volume occurred in the 0.8% doped sample, B2O3 molecules are closer to the side groups of PVDF and, therefore, the coordination bonds also occurred according to the interaction between them and as a result of this interaction a geometric deformation occurred on the morphology of B2O3. In consequence of this deformation, morphology of B2O3 gained net dipole moment and provided a contribution to the dipole moment density of the structure. Hence, higher dielectric constant values obtained than that of pure PVDF. At 1 kHz and 300 K, the real dielectric constant increased by 236% compared to that of pure PVDF. It was shown experimentally by the 0.8% doping level of B2O3 that decreasing porous and gap structure resulted a high dielectric constant. POLYM. ENG. SCI., 54:2536–2543, 2014. © 2013 Society of Plastics Engineers