Highly Fluorinated Poly(arylene ether ketone) Prepared by a CaH<sub>2</sub>‐Mediated Polycondensation Reaction
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Bibliographic record
Abstract
Abstract Summary: A new reaction procedure has been developed for the polycondensation of hexafluorobisphenol A (6F‐BPA) with bis(pentafluorophenyl) ketone (BPK) in dimethylacetamide (DMAc). In this reaction, CaH 2 has been used as a base to facilitate the formation of the phenolate; an alkali metal fluoride was used as a catalyst. Unlike the conventional polycondensation reactions, this procedure avoided producing water during the reaction, and hence, azeotropic distillation with the assistant of a low‐polar co‐solvent is not required. This improvement maintains the high polarity of the reaction medium; consequently, the selectivity of the reaction at the para ‐position of BPK is significantly enhanced and polymers with high molecular weights ( $\overline M _{\rm n}$ ca. 30 000 Da) can be obtained with very low branching contents (less than 3 mol‐%) and free of any cross‐linked gel particles. In addition to avoiding the formation of water in the reaction, the use of CaH 2 also reduced the concentration of the fluoride ion in the solution. These effects minimize chain degradation reactions such as hydrolysis. The use of CaO instead of CaH 2 for this reaction produces similar effects. In the case of CaO, traces of water can be introduced into the reaction. The presence of trace amounts of water increases the polycondensation rate, probably due to the enhanced ionization of the phenolate. However, it also causes a hydrolysis of polymer chains, resulting in the elimination of the ketone group in the polymer backbone. Fortunately, this side reaction is highly water and temperature dependent, and can be efficiently prevented by using CaH 2 or conducting the reaction at a lower temperature (<65 °C). CaH 2 ‐mediated polycondensation for the preparation of highly fluorinated poly(arylene ether ketone). image CaH 2 ‐mediated polycondensation for the preparation of highly fluorinated poly(arylene ether ketone).
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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 | 0.000 |
| 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 it