Effects of Brominating Matrimid Polyimide on the Physical and Gas Transport Properties of Derived Carbon Membranes
Why this work is in the frame
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Bibliographic record
Abstract
Bromination modification was initially carried out on Matrimid polyimide before undergoing carbonation to produce carbon membranes. Compared with unmodified Matrimid, brominated Matrimid shows lower chain flexibility, which is demonstrated by increased glass transition temperatures and molecular simulation results. Additionally, an increase in space between polymer chains was supported by fractional free volume (FFV) and d -spacing measurements. The improvement of chain rigidity of polyimide precursors serves to strengthen the membrane morphology during the production of carbon membranes. Thermal gravimetric analysis indicates that the thermal stability of polyimide decreases after bromination. The lower thermal stability and higher FFV value of brominated Matrimid result in higher gas permeability of carbon membranes pyrolyzed at a low pyrolysis temperature, while the selectivity remained competitive to those pyrolyzed from the original Matrimid precursor under the same conditions. However, the gas permeabilities of carbon membranes derived from modified Matrimid decrease significantly and become lower than those of carbon membranes from the original Matrimid, when the pyrolysis temperature is raised to 800 °C. This is due to the formation of more graphitic-like structure in carbon membranes from brominated polyimide, observed by the wide-angle X-ray diffraction. Therefore, it is concluded that bromination of Matrimid polyimide has significantly affected the pyrolysis behavior and the structure of the resulting carbon membranes. At a low pyrolysis temperature, carbon membranes derived from brominated precursors show attractive and superior gas separation performance.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 it