Synthesis of Linear Poly(tetrafluoroethylene-<i>c</i><i>o</i>-vinyl acetate) in Carbon Dioxide
Bibliographic record
Abstract
Tetrafluoroethylene (TFE) and vinyl acetate (VAc) were copolymerized in carbon dioxide by a free radical mechanism to yield a series of poly(TFE- co -VAc)s with weight-average molar masses, relative to polystyrene, between 110 and 209 kg mol -1 . The copolymer composition was controlled by the monomer feed concentration to have between 40 and 71 mol % TFE. Hydrolysis of the copolymer's vinyl acetate groups to vinyl alcohol (VA) yielded terpolymers, poly(TFE- co -VAc- co -VA), thereby providing a reactive functional group for further modification. Previous syntheses of poly(TFE- co -VAc) in aqueous media resulted in a branched structure due to radical hydrogen abstraction from VAc followed by continued propagation during polymerization. Consequently, a 10-fold or greater decrease in molar mass was observed following hydrolysis. Interestingly, after synthesizing poly(TFE- co -VAc) in supercritical carbon dioxide, only a small decrease in molar mass was observed after hydrolysis. This suggests that, in carbon dioxide, abstraction is suppressed relative to polymer propagation, thereby yielding predominantly linear poly(TFE- co -VAc).
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".