Effect of High Pressure Carbon Dioxide Exposure on the Permeation Properties of Asymmetric Polysulfone Membranes for Gas Separation
Bibliographic record
Abstract
In this study, the dependence of permeability on the feed pressure for glassy asymmetric polysulfone membranes has been investigated. Pure CO2 and CH4 were used as test gases. In pure gas experiments with CO2, the untreated membrane showed that the carbon dioxide permeation rate increased with increasing feed pressure from one bar onwards. This is because carbon dioxide behaves as a plasticizing agent by expanding the polymer lattice and increased the frequency of molecular motions of the polymer. Moreover, high carbon dioxide concentration in the polymer film disrupts the chain packing, thereby leading to a larger free volume and enhanced rates of segmental motions. Due to swelling of the polymer matrix, the structure of the polymer matrix is loosened and consequently polymer chains become more flexible. For the treated membrane, the permeability of carbon dioxide does not increase with feed pressure but gives a steady state value over the feed pressure ranges investigated. This was in agreement with scanning electron microscopy studies, which revealed that heat treatment densified the membrane skin layer. Thus, a subsequent heat treatment to the membrane is necessary in suppressing the plasticization effect.
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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) | 0.000 | 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 | 0.001 |
| 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".