No abstract

a-Crystalline form of PVDF doped with Boron oxide (B 2 O 3) 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% B 2 O 3 -doped PVDF as 25 and 9.7%, respectively. Because of the low specific volume occurred in the 0.8% doped sample, B 2 O 3 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 B 2 O 3 . In consequence of this deformation, morphology of B 2 O 3 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 B 2 O 3 that decreasing porous and gap structure resulted a high dielectric constant.

The different concentrations of the composites were prepared by mixing the 80 mass % of the base material Mn0 2 with 10 mass % V 2 O s and 10 mass % SnO (sample A), and with 15 mass % V 2 0 5 and 5 mass % SnO (sample B), respectively. The composite materials were examined using Fourier Transform Infrared (FT1R), X-Ray Diffraction (XRD), ac impedance and dc techniques. The XRD and FTIR numbers show the composites consist of the mixture of different phases, Mn 2 V20 7 , Mn 2 0 3 and Sn0 2 . During reaction at high temperature, it is found that tin (II) oxidizes to tin (IV) and Μη (IV) reduces to Mn (111). The conductivities of the composites were found to be within the semiconducting region (~3.67xl0' 7 S cm' 1 (xlO 2 S m' 1 ) for sample A and ~7.33xl0' 7 S cm"' (xlO 2 S m' 1 ) for sample B). The dielectric constants were calculated to be 59 for sample A and 36 for sample B, at -100 Hz, respectively.