Hydrophobically Modified Thermoresponsive Starch Nanoparticles for Use in Oil Recovery of Oil Sands

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Starch nanoparticles (SNPs) represent an interesting new hydrophilic water-dispersible material that is sold commercially as EcoSphere® by EcoSynthetix, our Supporting Organization. SNPs can be chemically modified with hydrophobic molecules. By careful adjustment of the hydrophobicity and number of molecules being attached onto SNPs, the SNPs can be induced to aggregate and even precipitate out of the aqueous solution by increasing the solution temperature above a critical temperature Tc. In effect, the modified SNPs respond to a thermal trigger and they have become thermo-responsive. This proposal is to optimize the thermo-responsiveness of the chemically modified SNPs for use as additives in oil recovery applications. The modified SNPs can interact with the oil trapped in oil sands at temperatures greater than Tc. These interactions between the oil and the modified SNPs will generate a stable emulsion which, after removal of the sand, can be destabilized by lowering the temperature below Tc. In so doing, the modified SNPs re-disperse in the water while the oil in the emulsion droplets diffuses toward the air-water interface where it accumulates. The oil can then be skimmed off while the water loaded with the modified SNPs can be re-used in another round of extractions. In principle, no waste water should be generated in the extraction which should minimize the formation of tailing ponds. The tasks that will be carried out in this proposal include the systematic modification of SNPs with small hydrophobic molecules such as butene or styrene oxide to make them thermo-responsive and large water-soluble polymers such as poly(ethylene glycol) to stabilize them in water, the assessment of their efficiency to extract oil from oil sands in the presence of different organic thinners such as octanol or toluene, and scale up extractions to model the extraction process. Chemical modifications of the SNPs will be conducted in the dry state in a Brabender mixer loaned to us by ECO so that experimental conditions can be easily transferred to the extruder operated by ECO to produce modified SNPs. This project will generate new materials with exciting properties that should be of high interest to the Canadian oil industry.