Correlation between Structure and Gas Transport Properties of Silyl-Modified Polysulfones and Poly(phenyl sulfone)s
Bibliographic record
Abstract
An improvement in gas permeation properties has been obtained by introducing bulky silyl side groups at sites ortho to either the ether or sulfone linkage of polysulfone and poly(phenyl sulfone) chains. The sizes of the substituents were systematically increased from trimethylsilyl, to dimethylphenylsilyl, and to diphenylmethylsilyl, and the degree of substitution was also controlled. The sterically smallest trimethylsilyl group substituted at the ortho ether site markedly increased the oxygen permeability from 1.1 to 7.1 barrers compared with that of unmodified polysulfone at a small tradeoff in oxygen/nitrogen selectivity. Unexpectedly, the oxygen permeability remained almost unchanged from polysulfone with the introduction of more bulky dimethylphenylsilyl and diphenylmethylsilyl substituents. It was also found that substitution at the sites ortho to ether linkage was more effective than the sulfone linkage in improving transport properties. The improved gas separation properties appear to be associated with increased free volume, evidenced from the increased d -spacing and specific volume. Further, the mobility of pendant substituents, characterized by dynamic mechanical analysis, correlated strongly with the d -spacing and specific volume. This leads us to the conclusion that it is substituent mobility rather than the size of the pendant side group that is the critical factor in determining free volume and transport properties.
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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 | 0.000 |
| 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 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".