GOALI: Routes to Improve Performance for Membrane Separation of Next Generation Biofuels for Transportation

Gasoline is generally blended with plant-derived ethanol, however, ethanol tends to increase the water content in the gasoline and decreases the engine performance. New engineering approaches allow for other fuel products to be produced from plant-derived sources, most notably butanol, which overcomes the aforementioned issues associated with ethanol. However, the butanol product is dilute in water and the water must be removed. Membranes provide a low cost solution to the butanol recovery, but there are performance trade-offs that limit its utility. This Grant Opportunity for Academic Liaison with Industry (GOALI) project will examine a new class of materials that could enable significant improvements in the performance of these membranes. Successful completion of this project would not only advance these membranes, but also accelerate their commercialization through the partnership with Promerus, LLC.

The project will examine an alternative BCP system based on polynorbornenes (PNB); PNB can exhibit a high glass transition temperature (>200 °C) and likely large free volume generally absent for high-Tg polymers that could enhance the flux. One critical challenge for BCPs is the development of low cost processing routes that are suitable for high volume manufacturing and yield well-defined microphase-separated structures. This project seeks to determine methodologies to controllable highly reproducible microphase-separated structures and understand their fundamental thermodynamic, dynamic and mechanical properties. Recently, Promerus LLC has developed new, functional group-tolerant polymerization initiators; enabling the synthesis of unique functionalized norbornene BCPs. It is hypothesized that the developed morphology will critically impact the membrane performance with likely trade-offs between flux and selectivity with the size of the hydrophilic/hydrophobic domains. This hypothesis will be tested using a series of copolymers by systematically varying the composition, molecular mass and alkyl side chain to understand how the BCP nanostructure acts to improve performance. The overarching goals of this project are to understand how the structure of the copolymer impacts properties critical to membrane operations and how to control this structure through processing techniques extendable to large-scale manufacturing. Fundamental investigations to elucidate morphology-mechanical property relationships and quantify impact of fouling and defouling on the mechanical, morphological, and separation properties, all as a function of processing conditions will be research. This work will provide fundamental processing-structure-property relationships for BCPs for separations and enable novel material designs for commercialization.