Date of Award
Doctor of Philosophy (PhD)
Materials Science and Engineering
Dr. Igor Luzinov
Dr. Konstantin Kornev
Dr. O. Thompson Mefford
Dr. Olga Kuksenok
Dr. Jeffery Owens
The current most efficient solution to fighting liquid pool fires involves the use of firefighting foams containing fluorinated surfactants. The physiochemical properties of these foams are considerably different to all other currently available firefighting foams. Fluorinated surfactants lower the surface tension to a point where the foam solution draining from the foam structure forms a continuous aqueous film on the surface of a volatile hydrocarbon fuel, adding an additional barrier to fuel vapor diffusion to the burning fire. For this reason, these foams qualify as aqueous film forming foams (AFFFs). However, fluorinated compounds are extremely harmful for the environment due to their chemical stability and resulting bioaccumulation. There are currently several industrially produced non-fluorinated firefighting foams available, but these foams possess gaps in their performance in comparison to AFFFs.
In this research, we grafted poly(oligo (ethylene glycol) methyl ether methacrylate) (POEGMA) brushes of different oligo(ethylene glycol) side chain lengths to the surface of hollow glass bubbles (GBs), prepared concentrated aqueous suspensions with these GBs, and used the suspensions to extinguish heptane pool fires. We investigated the effects the parameters of the grafted layer such as side chain length, graft density, molecular weight, and hydrophobic side chains have on the suspension properties—such as viscosity and surface and interfacial tension—and the firefighting performance of the suspensions. It was determined that, out of the GB suspensions studied, GBs with loosely grafted, high molecular weight POEGMA chains with large polyethylene glycol side chains (at least 19 ethylene glycol repeating units) on the surface provided suspensions (in conjunction with a low surface energy siloxane surfactant) with low viscosities, complete spreading over a liquid hydrocarbon (hexadecane) surface, and low heptane fire extinguishment times. The extinguishment times of these low-viscosity GB suspensions were approximately equivalent to the AFFF extinguishment time, but the suspensions offer highly superior protection against reignition of the fire following extinguishment.
Overall, this dissertation provides insight into the utilization of a new class of materials for extinguishment of liquid hydrocarbon fires. The GB suspensions reported herein represent fluorine-free fire extinguishing materials which offer the opportunity for reuse following extinguishment. Our understanding of these suspensions and the specific physiochemical properties which contribute to their effectiveness in fire extinguishment lays the groundwork for further exploration of low-density aqueous suspensions for extinguishment of liquid hydrocarbon fires.
Snipes, Randall, "Glass Bubbles Grafted With Polymer Brushes for Liquid Hydrocarbon Fire Extinguishment" (2023). All Dissertations. 3425.
Author ORCID Identifier