Rigorous Deasphalting, Autoxidation, and Bromination Pretreatment Methods for Oilsands Bitumen Derived Asphaltenes to Improve Carbon Fiber Production
Bibliographic record
Abstract
Carbon fiber production from asphaltenes was identified as a potential noncombustion process to add value to the n -pentane insoluble fraction of oilsands bitumen. Methods to pretreat the asphaltenes before melt spinning to improve its properties for carbon fiber production were investigated. Oilsands bitumen derived asphaltenes from an industrial n -pentane solvent deasphalting process served as raw material for this study. The material was characterized before and after pretreatment, and the melt spin properties were evaluated. Selected carbon fiber products were also oxidatively stabilized and carbonized to be characterized as carbonized carbon fibers. It was found that pretreatment by rigorous n -pentane and n -heptane deasphalting, autoxidation (190–250 °C), and bromination with Br 2 (150–170 °C) followed by debromination (200 °C) had a minor impact on the CHNS elemental composition. At the same time, noticeable changes were found in the physical properties of the pretreated products with an increased softening point temperature for melt spinning. In most cases, the melt spin productivity was improved. The exception was the poorer melt spin productivity for n -heptane insoluble material, which was tentatively ascribed to a lack of lighter material to act as plasticizer. Variability in the fiber diameter of carbonized fibers was noticeably reduced by autoxidation as pretreatment even at the mildest conditions studied. Yet, despite the noted effects of pretreatment on physical properties and melt spin behavior, it was found that pretreatment did not cause a meaningful change in the tensile strength or Young’s modulus of the carbonized fiber products compared to carbon fibers produced from the industrial asphaltenes without any pretreatment.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".