Study on Synthesized Thermoresponsive Block Copolymer for Water-Based Oil Sands Extraction

Abstract

Thermoresponsive nonionic block copolymers, methoxy poly­(ethylene glycol)-b-poly­(N-isopropylacrylamide) (MPEG-b-PNIPAM), were investigated as chemical aids for the water-based oil sands extraction process. Two copolymers with different chain lengths were synthesized by means of atom transfer radical polymerization (ATRP) in our lab. Their chemical structures were characterized by FT-IR and 1H NMR spectroscopy. Moreover, their thermoresponsive property was demonstrated by the results of the turbidity and hydrodynamic size measurement. The thermoresponsiveness permits these novel block copolymers to be easily deployed and dissolved in the process water at ambient temperature while also being transformed to an interfacial-active state at the elevated operating temperature. The bench-scale oil sands extraction tests showed that the overall recovery could be improved with polymer additions. Further investigations revealed that both block copolymers could improve the bitumen liberation process. However, the polymer with a longer MPEG chain length exhibited a negative impact on the bitumen–air bubble attachment and hence was detrimental to the froth quality. The results of this study provide a valuable proof-of-concept that the synthesized thermoresponsive nonionic block copolymer can be a promising chemical aid for the water-based oil sands extraction process.

Role of Surfactants Based on Fatty Acids in the Wetting Behavior of Solid–Oil–Aqueous Solution Systems

“…Here, the electric double-layer repulsion could be safely ruled out because of the nonionic nature of MEA-FA pairs adsorbing at the interfaces. Meanwhile, an effective steric repulsion is less likely to arise from the short chain of the hydrophilic head exposed to the aqueous phase of the thin film. , As a result, the different thin-film stability of two surfactants appears to be insufficiently explained by the modifications of the electric double layer and/or steric forces, both of which are normally considered as two major contributors to the disjoining pressure in terms of the influence from adsorbed substances at the interface according to the literature. , …”

“…Meanwhile, an effective steric repulsion is less likely to arise from the short chain of the hydrophilic head exposed to the aqueous phase of the thin film. 38,42 As a result, the different thin-film stability of two surfactants appears to be insufficiently explained by the modifications of the electric double layer and/or steric forces, both of which are normally considered as two major contributors to the disjoining pressure in terms of the influence from adsorbed substances at the interface according to the literature. 36,37 The thin-film drainage process relies on the approach velocity as well as the hydrodynamic boundary conditions in the theoretical treatment of the drainage flow.…”

Thermo-responsive block copolymers: assembly and application

“…In the former case, the thermo-responsive polymers become hydrophobic from the hydrophilic state in solvents as temperature increases, while in the latter case thermo-responsive polymers become hydrophilic from the hydrophobic state. In the current literature, LCST-type thermo-responsive polymers are mostly studied, which mainly include polyacrylamides, [63][64][65] polyethylene oxides, [66][67][68][69] polyacrylates [70][71][72][73] and polyimidazoles, 43,74,75 which can undergo phase transition in water, and their applications in biomedical 76,77 and wastewater treatment 4,43,58 are investigated. UCST-type thermo-responsive polymers are mainly amphiphilic polyelectrolytes, such as polysulfone betaines, 78,79 poly(N-acryloyl glycinamide) 27,80 and ionic polypeptides.…”

“…Thermo-responsive block copolymers, 1–35 which can respond to external temperature stimuli, are block copolymers containing one or more than one thermo-responsive blocks. They have received wide attention in the fields of catalysis, 36–41 adsorption and separation, 42 wastewater treatment, 43 sensors, 44,45 imaging, 46,47 drug delivery 48 and so on.…”

Thermoresponsive Starch Nanoparticles for the Extraction of Bitumen from Oil Sands

“…These polymers become hydrophobic and form aggregated species at temperatures above the LCAT. Han et al were thus able to extract bitumen from oil sands with the block copolymer methoxy poly(ethylene glycol)-b-poly(N-isopropylacrylamide) (MPEG-b-PNIPAM) [16]. Below the LCST of PNIPAM, the block copolymers are freely soluble in water.…”