The Polymer Reaction Engineering Lab is located in the F building, overseen by Dr. Allison Scott, and it focuses on polymer design research. Dr. Scott, herself has been conducting polymer research since her high school days. Starting from the health and environmental effects of polytetrafluoroethylene (Teflon) to her PhD work that evaluated polymer properties in reference to enhanced oil recovery [process of extracting oil that has not been recovered through conventional techniques]. In the same vein, the current projects that are being conducted in the PRE-lab are varied but focus on how polymers can be used for agricultural applications and wastewater treatment. Dr. Scott emphasised the importance of researching polymers sustainably, something she also highlights in her own research by using a statistical design of experiments rather than a trial-and-error model.
Polymer design research is based on three stages – making the polymer (synthesis), understanding its chemical properties and testing the application of the polymer. The process of reacting monomers to create polymers is the most crucial part and is one of the main objectives of the lab. The process has many complications and requires a lot of precision. The exact measurements for the pre-polymer formulation, where it exists in either a liquid or solid [powdered or crystallized] form are measured using the balances and weighing scales.
An initiator is used to convert the monomers to the polymers; this combination is then put into the shaking heating bath. This process is conducted under the fumehood, where most of the polymer synthesis steps take place. Since the initiator can react with oxygen rather than the monomer used, the process must be conducted under the nitrogen air space [glove box]. Most of the air-free synthesis preparation takes place here. After polymerization, the final result is a cloudy solution, for which a precipitation step (with non-solvent) is used. The requirement, however, is a powdered solution so that it can dissolve easily in water – therefore, the solution is filtered and is put into the vacuum oven. The oven maintains a low pressure (a vacuum) to dry the polymer samples, as a large amount of heat could degrade the polymer. Once the final polymer is achieved, properties like resistance to flow are tested on the rheometer. For the molecular weight, Gel Permeation Chromatography (GPC) is used. It finds the molecular weights by separating molecules based on size as they elute through a column filled with porous material.
Dr. Scott’s main lab-related tasks are to supervise the graduate students, guiding with research direction, reviewing new operating procedures and developing new protocols. The lab work is largely performed by the graduate students and the research they do focuses on water soluble polymers that can either dissolve or swell in aqueous systems to clear up wastewater or other organic matter. For example, one student is working on polymer design for emerging contaminants from acute water quality events e.g., droughts, forest fires etc, such that water quality concerns can be addressed quickly and efficiently.
Polymers are used for water treatment because they are charged and have long chain lengths, thus can attach to contaminants that are suspended in the water. This increases their weight and the newly formed ‘floc’ settles at the bottom and can be easily removed. The use of GPC is essential since polymers need to be of a certain length [length can be found by individual molecular units], because shorter polymers do not attach to the pollutants and can add to chemicals suspended in water. This creates more waste, therefore more sludge and more cost of removal.
Another student’s thesis topic that revolves around wastewater treatment is the treatment of septic system wastewater using biopolymers instead of synthetic polymers. Biopolymers have lower environmental impact compared to synthetic polymers by contributing to the circular economy and being biodegradable. Another project is analysing slow-release fertilizer hydrogels. Synthetic fertilizers readily dissolve in irrigation water and cause nutrient release that the plants cannot keep up with, they also cause leaching and water contamination. Hydrogels can release moisture and fertilizers at a slow rate to retain moisture and provide consistent nutrient uptake.
As a final water treatment example, Abigail O’Toole, is working towards the detection and elimination of polyfluoroalkyl substances (PFAS) in municipal water. PFAS is very common in both industry and households [most waterproof items] and can be a source of contamination in municipal water systems. Furthermore, there are no strict guidelines regarding PFAS in Canada, which can lead to excessive contamination. Removal methods in municipal treatment plants are expensive and do not target all PFAS contaminants because of the different sizes and types that exist. The focus of Abigail’s research is to create an absorbent that is both inexpensive and versatile enough to remove short and long chain PFAS.
As Dr. Scott puts it, “[The projects] are pretty distinct - they are all polymer design, but the applications are very different.”. The PRE Lab has its graduate students working towards the common goal of sustainable and environmentally beneficial polymer production. Research is a continuous and ever-evolving process that is passed on from one group of graduate students to another. Once the current research is complete, new graduate students will come to the lab and begin their exploration into the infinity that is polymer application research. The lab holds on to polymer samples from former students, mirroring the idea of no final conclusion for research and the endlessness of human discovery.