Membrane Science Commons^™

Design And Characterization Of Lignin-Based, Thermoresponsive Soft Composites With Improved Mechanical And Transport Properties, Missoury D. Wolff

All Dissertations

In an attempt to reduce reliance on petroleum-based polymers, lignin – an abundant biopolymer – has gained popularity as a sustainable alternative. However, research on lignin-containing soft composites – i.e., hydrogel (bio)composites – has largely been heuristic, providing limited insight into the fundamental structure-processing-property relationships that govern performance improvements in this emerging class of ‘green’ soft composites. As such, this dissertation presents a systematic investigation of how lignin molecular weight (MW), composite composition, and the concentrations of crosslinker and accelerator impact the mechanical and transport characteristics of soft composites composed of lignin, poly(N-isopropylacrylamide) (PNIPAm), and poly(vinyl alcohol) (PVA).

In the …

Elucidating The Impact Of Casting Solvent On Vanadium Ion Transport In Solution-Cast Ionomer Biocomposites Containing Lignin, Zhongyu Wang

All Theses

This paper attempts to investigate the influence of solvent choice to the Nafion-lignin proton exchange membranes that used in the vanadium redox flow batteries. The influence of two different solvents: DMF and DMSO were investigated in this paper. Results show that when using DMSO as solvent, Nafion-lignin membranes' vanadium ion cross over can be greatly reduced in comparing with membranes prepared from DMF. Also, membranes prepared from DMSO also show higher water uptake ability and lower ion exchange capacity than the membranes prepared from DMF. This paper has also investigated the influence of lignin type to the membranes. Results show …

Sulfonated Lignin-Based Ionomer Biocomposite Membranes For Redox Flow Batteries, Aiswarya Mechoor

All Theses

The current benchmark membrane for vanadium redox flow batteries (VRFBs), Nafion™, accounts for up to 40% of the cost of the battery and suffers from poor ion selectivity, leading to diminished battery performance. Consequently, alternative ionomer membranes, such as sulfonated poly(ether ether ketone) (SPEEK), have recently garnered attention due to their lower cost and similar performance properties to Nafion. However, like Nafion, SPEEK also suffers from poor ion selectivity. In this study, we attempt to address the issue of poor ion selectivity by developing SPEEK–lignin composite membranes containing fractionated and functionalized lignin. Specifically, two lignin fractions – a low molecular …

Amine-Functionalized Lignin-Based Ionomer Nanocomposites For Redox Flow Batteries, Joshua Wilder

All Theses

As the development of energy storage technologies for renewable energy sources continues to garner attention, vanadium redox flow batteries (VRFBs) have emerged as promising source for grid-scale energy storage. A major component of the VRFB is the ion exchange membrane (IEM), as it serves to physically separate the two liquid electrolytes and also directly impacts the battery’s capacity, efficiency, and cost. The current industry standard IEM, Nafion™, not only accounts for a large portion of the cost of the VRFB but also suffers from poor proton selectivity. Herein, we have synthesized sulfonated poly(ether ether ketone) (SPEEK) composite membranes containing amine …