Physical and Gas Transport Properties of Asymmetric Hyperbranched Polyimide-Silica Hybrid Membranes
Bibliographic record
Abstract
Physical and gas transport properties of the asymmetric hyperbranched polyimide (HBPI) -silica hybrid membranes prepared with a dianhydride, 4,4’-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and an asymmetric triamine, 2,4,4’-(triaminodiphenyl)ether (TADE), were investigated and compared with those of the symmetric HBPI-silica hybrid membranes prepared with a symmetric triamine, 1,3,5-tris(4-aminophenoxy)benzene (TAPOB). The HBPI-silica hybrid membranes were prepared via sol-gel reaction using hyperbranched polyamic acid of which end groups were modified with silane coupling agents, water and tetramethoxysilane. The thermal mechanical and dynamic mechanical analysis measurements confirmed that the rigidity of asymmetric HBPI was higher than that of symmetric HBPI because of the rigid and asymmetric structure of TADE monomer. In addition, the degree of branching of asymmetric HBPI is lower than that of symmetric HBPI because of the different reactivity of the three amino groups included in TADE. The rigidity and linearity of HBPIs had an effect on the progression of sol-gel reaction, consequently the gas transport properties. The increasing of the gas permeability coefficient of the asymmetric dianhydride(DA)-HBPI-silica hybrid membranes with increasing silica content was smaller than those of symmetric DA- and amine(AM)-HBPI-silica hybrid membranes. In addition, the gas permeability coefficient of the asymmetric AM-HBPI-silica hybrid membranes decreased with increasing silica content. This was due to the fact that the dispersibility of silica in the asymmetric HBPI-silica hybrids, of which polymer chain was more rigid and linear than those of symmetric HBPI-silica hybrid, was not as fine as in the symmetric HBPI-silica hybrids, and that the long and tortuous diffusion path was newly formed by hybridization with silica.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
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) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 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 teacher head, 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".