SYNTHESIS OF CARBOXYMETHYL CHITOSAN AND ITS APPLICATION FOR PROTON EXCHANGE MEMBRANE FUEL CELL

• Main Author: Pradhana Jayusman S., Adit
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/71567
• Institution: Institut Teknologi Bandung

Chitosan membranes have a bright future as a proton exchange membrane in proton exchange membranes fuel cell (PEMFC). However, chitosan membranes’ proton conductivity is inferior compares to Nafion®. Therefore, a modification is needed to improve chitosan’s proton conductivity. The aim of carboxymethyl chitosan (CC) synthesis is to improve the ion exchange capacity (IEC) and proton conductivity of chitosan membranes by forming an amphoteric system (O-carboxymethyl chitosan, OCC). CC can be synthesized from chitin and chitosan as starting materials. From the experiments, CC has been synthesized succesfully by reacting chitosan (degree of deacetylation 83.23%) with chloroacetic acid, heterogenously. Infra-red spectra and thermogravimetri analysis results indicate that CC membranes have higher hydrophilicity and water content than of chitosan membranes. CC membranes’ IEC have the same magnitude as chitosan, but membrane potential analysis of CC membranes indicates that it has higher effective charge than chitosan. Impedance spectroscopy results indicate that CC membranes’ proton conductivity is higher than chitosan and show a different proton transport mechanism as observed in threshold frequency. However, the presence of carboxymethyl groups substituents in CC membranes increase the fragility of membranes, decrease the thermal stability, and also increase membranes’ methanol permeability relative to chitosan membranes. Some improvements, especially in mechanical and fuel barrier properties, are required to compete with Nafion®.