Bibliographic record
Abstract
Teflon AF 2400 membranes containing various weight percent FC-70 were cast from FC-72 solution. The membrane surface is hydrophobic as shown by contact angle measurement. Free volume in Teflon membranes was calculated by measuring the membrane density using the hydrostatic method. Differential scanning calorimetry (DSC) and thermomechanical analysis (TMA) were conducted to study the thermal transitions of Teflon AF membranes. The glass transition temperature of Teflon membranes is -63 ¡ãC at 5 wt% FC-70 in comparison with 240 ¡ãC at 0 wt% FC-70. The permeability of Teflon membranes was investigated by transport experiments. The four probe solutes were toluene, ¦Á,¦Á,¦Á-trifluorotoluene, nitrobenzene and pentafluoronitrobenzene. The permeability coefficients of the probe solutes are found to be very sensitive to the FC-70 content and the temperature. The permeability coefficients of all solutes change with FC-70 in a similar way. They decrease initially as FC-70 content increases at low FC-70 concentration with reversal of this trend at higher FC-70 concentration, and decrease again and finally level off. Teflon AF membranes with less than 10 wt% FC-70 could be associated with the polymer¡¯s anti-plasticization, an effect indicated by a reduction in the free volume, a decrease in the glass transition temperature and a reduction in the partition ratio and permeability coefficient. Teflon AF membranes with 10 wt% FC-70 or more could be plasticized, resulting in lower glass transition temperature, higher free volume and higher permeability coefficient. Selectivity of the membranes was investigated for the pair ¦Á,¦Á,¦Á-trifluorotoluene/toluene and for the pair pentafluoronitrobenzene/nitrobenzene. It reaches a maximum at 10 wt% FC-70 for both pairs at 20oC. 10 wt% FC-70 is likely a turning point of plasticization, which is quite interesting since it is also related to the highest selectivity.Teflon AF membranes could also be plasticized by the organic liquid with which it is in contact. Chloroform seems to plasticize the membranes (they get pliable) and change the properties of the membranes to a less ¡®fluorous¡¯ environment. The concentration of FC-70 may change during transport experiments. We thus need to find a means to plasticize the films while keeping them fluorous.
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 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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".