2021 Virtual Undergraduate Research Symposium

2021 Virtual Undergraduate Research Symposium

Influence of living ends on polyethylene based anion exchange membranes

Influence of living ends on polyethylene based anion exchange membranes

PROJECT NUMBER: 12 | AUTHOR: Ryan Park​, Chemical and Biological Engineering

MENTOR: Andrew Herring​, Chemical and Biological Engineering

GRADUATE STUDENT MENTOR: Ivy Wu​, Chemical and Biological Engineering

ABSTRACT

Anion exchange membranes (AEMs) are used to selectively permeate anions and their ability to effectively do this is imperative for the function of fuel cells and desalination processes. Our research group has developed a robust family of triblock copolymer AEMs, and our previous investigations suggest the polymeric living ends may influence AEM performance. In this study, we investigated the influence of these living ends on our polychloromethylstyrene-polyethylene-polychloromethylstyrene AEM quaternized with methylpiperidine and their performance compared to a commercially produced membrane called Fumasep. The membranes were characterized for ion exchange capacity, water uptake, and conductivity. Additionally, performance was measured using anion diffusion and migration tests to determine the membranes physical characteristics and its potential to serve as an effective AEM. The IEC tests showed that the triblock copolymer membranes had higher IEC values of 1.86 and 1.77 for living ends and non-living end, respectively, while Fumasep has a literature value of 1.50. The water uptake tests showed Fumasep had a significantly lower water uptake of around 17% while the two synthesized membranes had water uptake values of 130% and 190% for the living ends and non-living end. The liquid conductivity tests were performed and the membrane with living ends had a conductivity of 1.07 S/m and the one without a conductivity of 0.395 S/m. The anion diffusion tests showed that our membranes were able to diffuse almost double that of Fumasep over the same time interval and the addition of an electric potential increased the mass transport of every membrane slightly. Based on the performance tests the membranes synthesized by our lab show more promising results for commercial application due to the increased selectivity and mass diffusion rates. In general, the living end groups result in characteristics that are more desirable for commercial application due to the higher ion exchange capacity, smaller in-plane swelling, higher conductivity, and larger mass transport.

PRESENTATION

AUTHOR BIOGRAPHY

Ryan Park is currently a junior in chemical engineering on the biology track. He is doing research for the chemical and biological engineering department under Dr. Andrew Herring. His research has focused on the characterization of the research groups membranes and he hopes to help the research group in producing a commercially viable membrane.

5 Comments

  1. Remarkable work.

  2. Great presentation, easy to understand for someone without a diverse chemistry background!

    • Thanks Bennett,
      I am glad you were able to understand and enjoy the presentation.

  3. Good job on your presentation! What polymerization technique are you using to create the living ends of your triblock copolymer?

  4. Thanks Griffin,
    The polymer was created using a chain-transfer ring-opening metathesis polymerization (CT-ROMP) technique and the polycyclooctene was later hydrogenated into polyethylene.

    W. Zhang, Synthesis and Characterization of Polymeric Anion Exchange
    Membranes, University of Massachusetts Amherst, Polymer Science and
    Engineering, 2016. https://doi.org/10.7275/8428485.0

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