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https://ptsldigital.ukm.my/jspui/handle/123456789/520451| Title: | Development of poly(vinyl alcohol)-based composite membrane for proton exchange membrane fuel cells (PEMFCS) application |
| Authors: | Wong Yun Yik (P92272) |
| Supervisor: | Wong Wai Yin, Dr. |
| Keywords: | Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia Fuel cells Proton exchange membrane fuel cells Membranes (Technology) |
| Issue Date: | 11-Aug-2021 |
| Description: | This study focuses on the use of poly(vinyl alcohol) (PVA) as proton exchange membrane (PEM). A series of strategies was attempted to optimise the PVA membrane properties. Firstly, sulfonation of PVA (PVA) followed by polymer blending with chitosan (CS) were executed to synthesise CS/SPVA membrane. Two different sulfonating agents, namely sulfosuccinic acid (SSA) and 4-sulfophathalic acid (SPTA) were investigated, along with different blending ratios of CS:SPVA. Sample with ratio of 15:85 (CS/SPVA15-SSA) produced from SSA was found to exhibit the most significant proton conductivity and ion exchange capacity (7.34 mS/cm and 2.307 mequiv/g, respectively). In the next stage, Taguchi optimisation was performed with the parameter of addition of hydrophobic crosslinker, glutaldehyde (GA), crosslinking temperature and crosslinking duration to improve both hydrolytic stability and proton conductivity. The optimisation was found on a combination of no GA addition, crosslinking temperature at 110 °C and duration of 90 min. The water uptake was recorded from 215.9 % to 82.05 %, and proton conductivity from 7.34 mS/cm to 8.21 mS/cm (at 80 °C). Following, the addition of different inorganic fillers of titanium dioxide (TiO2), silicon dioxide (SiO2) and sulfonated graphene oxide (SGO) were attempted to further improve the hydrolytic stability and mechanical properties. The optimised CS/SPVA15-SSA membrane with SGO of 2 wt.% had resulted in the water uptake reduction to 72.48 %, alongside a slight trade-off of proton conductivity (at 6.75 mS/cm). Besides that, improvement in mechanical stability also found with the elastic modulus increased from 67 MPa (with no inorganic filler) to 108 MPa at the temperature of 80 °C. Lastly, physical properties and proton transport mechanism in the CS/SPVA15-SSA membrane were investigated and validated through molecular dynamic (MD) simulation. The simulation results indicating well miscibility between CS and SPVA, and confirmed with experimental results on improved mechanical and thermal stability on the CS/SPVA15-SSA membrane. Meanwhile, Arrhenius plot on proton conductivity and radial distribution functions (RDF) study validated that the proton transport was governed by Grotthuss mechanism. This project had concluded that the integrated approach successfully improved the hydrolytic stability of the membrane while achieving satisfactory proton conductivity as an alternative PEM.,Ph.D. |
| Pages: | 192 |
| Publisher: | UKM, Bangi |
| Appears in Collections: | Fuel Cell Institute / Institut Sel Fuel |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| ukmvital_123915+SOURCE1+SOURCE1.0.PDF Restricted Access | 4.1 MB | Adobe PDF |  View/Open |
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