Preparation of boron phosphate reinforcedpbi based composite membranes and examination of properties

In this study, it is aimed to prepare cast composite membranes which reinforced with boron phosphate (BPO4) and PBI (polybenzimidazole) based fiber. Polybenzimidazoles are prepared from hydroxamoyl chloride and diamino monomers in the DMF (dimethylformamide) atmosphere at 150 ᵒC without catalyst. The 20 % polybenzimidazole solution was prepared in a PVDF (polyvinylidene fluoride), BPO4 PBI-1 (1: 1: 1) homogenizer with a sol-gel method using DMF / acetone solvent pair in order for fiber. Fiber deposition was done on the aluminum foil at a distance of 15 cm with 20 kV voltage in order to provide fiber electrospin. In this study, it also PVDF/BPO4/PBI-1 (PBM-1), PVDF/BPO4/PBI-2 (PBM-2), PVDF/PBI-2(PM-2) and PVDF/PBI-1(PM-1) composite membranes were synthesized. The water uptake and ion exchange capacities were measured for fiber and cast composite membranes; scanning electron microscopy (SEM), surface contact angle measurement, proton conductivity measurement, fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric (TGA) analyzes were performed. BPO4 has been confirmed in the presence of X-ray diffractometry (XRD) analysis for PBFM-1, PBM-1ve PBM-2 membranes. In addition, the RMS value of the fiber of the PBFM-1 membrane was found to be 113.404 nm by the atomic force microscope (AFM). Proton conductivity measurements were made at different temperatures and the best results were reached at PBM-2 casting membrane at 120 ° C (7.1 × 10-2 1 / Ω × cm). The ion exchange capacities were ranged from 3.12 to 5.68 mmol g. It observed that founded values were higher than the values (0.91 mmol /g) obtained for Nafion membrane. Keywords: Boron phosphate, Composite membrane, PBI hybrid