Electrospun Green Fibers from Alberta Oilsands Asphaltenes

Alberta oilsands asphaltenes (AOAs) are carbonrich hydrocarbons obtained from the heaviest fraction in Alberta oilsands bitumen. They have little value in the current market. Asphaltenes are considered a problematic stream for bitumen transportation and processing, and they may be a potential feedstock for carbon fiber (CF) production. Effort has been devoted by researchers and the oil industry for developing asphaltenes into value-added products, in particular CFs. Major barriers have been identified for the conversion of asphaltenes to CFs. One of them is purification and priming of the AOA feedstock as the raw material varied significantly from extraction and applied isolation technologies. Here, we report the purification of raw AOAs for the purpose of forming AOA-green fibers through electrospinning, the comparison with the non-purified AOA raw materials, and the validation of the potential of conversion of asphaltenes toward CFs. Thermogravimetric analysis, elemental analysis, and scanning electron microscopy were carried out. AOA-green fibers were obtained with the as-received AOAs and the maltene-free AOAs by three optimized electrospinning protocols. These green fibers can be spun to a large size mat with a high degree of alignment through adjusting the collector rotation velocity. The diameters of the obtained AOA-green fibers are mostly in the range of 4-15 mu m. The green fibers from the as-received AOAs could sustain up to 200 degrees C in air but fused with further increase of temperature, while the green fibers from the purified AOAs showed improved mechanical strength and were able to withstand temperatures up to 300 degrees C in air without fusing. This work will be of interest to the CF industry as a potential alternative approach for low-cost precursors.

Automated summary

This study reports on the purification of raw AOAs for the purpose of forming AOA-green fibers through electrospinning, and validates the potential of converting asphaltenes into carbon fibers. The purified AOAs showed improved mechanical strength and were able to withstand higher temperatures.