Phosphoric acid (PA)-doped polybenzimidazole (PBI) proton exchange membranes have received attention because of their good mechanical properties, moderate gas permeability, and superior proton conductivity under high temperature operation. Among PBI-based film membranes, nanofibrous membranes withstand to higher strain because of strongly oriented polymer chains while exhibiting higher specific surface area with increased number of proton-conducting sites.In this study, PBI electrospun nanofibers were produced and doped with PA to operate as high temperature proton exchange membrane, while changes in proton conductivity and morphologies were monitored. Proton conductive PBI nanofiber membranes by using the process parameters of 15 kV and 100 μL/h at 15 wt% PBI/dimethylacetamide polymer concentration were prepared by varying PA doping time as 24, 48, 72, and 96 hours. The morphological changes associated with PA doping addressed that acid doping significantly caused swelling and 2-fold increase in mean fiber diameter. Tensile strength of the membranes is found to be increased by doping level, whereas the strain at break (15%) decreased because of the brittle nature of H-bond network. 72 hour doped PBI membranes demonstrated highest proton conductivity whereas the decrease on conductivity for 96-hour doped PBI membranes, which could be attributed to the morphological changes due to H-bond network and acid leaking, was noted. Overall, the results suggested that of 72-hour doped PBI membranes with proton conductivity of 123 mS/cm could be a potential candidate for proton exchange membrane fuel cell. Figure 1) is capable of absorbing acids (pKa~5.5), which is essential to be used in fuel cell membranes and other protonconducting applications. 2 To overcome the drawbacks of the low-temperature proton exchange membrane fuel cell (PEMFC) such as CO catalyst poisoning, necessity of humidification, heat management, and low diffusion rates of protons, PBI-based membranes were preferred because of their superior proton conductivity particularly both at high temperatures 3-5 and at 0% relative humidity. 6 Phosphoric acid-doped polybenzimidazole membranes were first successfully prepared by Wainright et al. 7,8 These membranes were recommended as electrolyte for high-temperature proton exchange membrane fuel cell (HT-PEMFC) operating at temperatures of up to 200°C. 8,7 They also exhibited good mechanical properties and low gas permeability [9][10][11] compared to water-containing membranes including Nafion whose proton conductivity decreases with increased temperature because of the evaporation of H 2 O molecules. 12 In addition, the results showed that an increase in doping level resulted in better proton conductivity and so more efficient HT-PEMFC performance. 7,13 After blended with PA, PBI films might suffer from deterioration because of the slow elution of water-soluble PA, when the vapor was produced. 14 Moreover, it was reported that these film membranes also sacrificed the

With the increases of the expected properties of textile products, better and advanced new designs are being created. Textiles used in vehicles are increasing, and the current performance of the expectations bar is determined by automobile manufacturers. While meeting the expectations of users in the vehicle mechanically, but also disturbing the user during operation of the mechanical properties of this ratio should be minimized. This study was intended to minimize sound transmission of nonwoven textile components, which are used in cars as silencer parts. For that purpose, four different models were developed in this study. First model consists of three designs for baggage carpets. Second model has six designs for floor coverings. Third model comprises two designs inner dash felt and finally fourth model includes two designs of hood liners. The acoustical absorption coefficients and transmission loss of these carpets were tested and evaluated in the frequency range of 16-6300 Hz. The measurements demonstrated that nonwoven layer is a very significant and effective part of a carpet due to its contribution in the sound isolation. With this study, it has been determined which layer has better performance on sound absorption and transmission loss among different carpet types. A combination of heavy layer and nonwoven layer carpets is found to be benefit for noise and sound insulation.