Effect of Sulfuric Acid on the Physiochemical Properties of Chitosan-PVA Blend for Direct Methanol Fuel Cell

In this work, we have successfully cross-linked the different weight ratio of Chitosan-PVA blend with sulfuric acid. The effect of cross-linker on the properties of blends are studied by using different experimental technique. The cross-linked membrane provides higher ion exchange capacity due to the procurement of extra ionic hooping sites in the membrane. The compatibility of the blends are confirmed from the FTIR and DSC analysis. The crosslinking reaction fastening the phase transition behavior of the blends which reduces the glass transition temperature. The highly compatiblized cross-linked blend provides higher tensile strength and lower modulus at moderate temperature. The significant reduction of weight loss was observed in a cross-linked membrane which enhances thermal stability of the blend. The group which are responsible for higher methanol cross-over are consumed by the cross-linking reaction and a drastic reduction of methanol cross-over was observed. The proton conductivity of the blends are obtained by performing experiment in a four probe impedance analyzer and fitting the EIS data in an equivalent circuit model. At moderate temperature, the cross-linked membrane provides higher proton conductivity than the pure membrane and the proton transport was controlled by Grotthus mechanism. The cross-linked membrane provides higher proton conductivity and membrane selectivity which is beneficial for DMFC design.

Automated summary

In this study, the cross-linking reaction improved the properties of Chitosan-PVA blend, enhancing the ion exchange capacity and thermal stability, reducing the glass transition temperature, and decreasing methanol crossover, resulting in higher proton conductivity.