Poly Sulphone Lab Report

2.2. AEM preparation

The poly sulphone based anion exchange membrane was prepared using three methods: (1) chloromethylation, (2) quaternization and (3) alkalization. The schematic diagram for the preparation of the QPSU is shown in Fig. 1.

[Figure 1]

2.2.1. Chloromethylation of poly sulphone

5 g of polysulphone was dissolved in 75 mL of chloroform at 70°C. After complete dissolution of polymer, a mixture of paraformaldehyde (3.4 g) and chlorotrimethylsilane (14.7) mL was prepared as the chloromethylating agent with constant stirring which was followed by the addition of 5% of stannous chloride (by weight, of polymer) as catalyst with stirring at 70°C and allowed to react for 18 h. Then the polymer was precipitated in methanol to eliminate

The alkalized membrane was then washed with de-ionized water several times and soaked in de-ionized water with numerous washings for 24 h prior to next step of operation. The ion exchange capacity (IEC), hydroxyl conductivity, water absorption percentage, oxygen and substrate crossover and thickness of the membranes were determined and the obtained values are tabulated (Table 1).

[Table 1]

2.3. Characterization of membranes

2.3.1. Structural characterization of membranes

The chloromethylation and quarterization of poly sulphone (PSU) were confirmed with an FTIR Alpha Bruker spectrometer in transmittance mode and 1H NMR Bruker Advance 500 MHz multinuclear FT-NMR spectrometer.

2.3.2. Topological characterization of membranes

The surface morphology of the prepared membranes were viewed using Hitachi S-3400N model scanning electron microscope. The surface roughness of the membranes were obtained using a non-contact profilo meter (Taylor Hobson hardness tester) and the respective average roughness (Ra) values were calculated using Taly Map Platinum 5.1.1.5374 software.

2.3.3 Electrochemical measurements

2.3.3.1. Cyclic