Crosslinking of polyamides using dianhydrides, diacid chloride and dialdehyde: a promising approach for water treatment
Bibliographic record
Abstract
Abstract New crosslinked polyamides were successfully produced from the condensation of pre‐synthesized monomer, 5‐(2,2,2‐trifluoroacetamido)isophthaloylchloride (TFAIAC) and diamines at low temperature. These polyamides were used as promising metal‐chelating adsorbents due to the presence of O and N donor sites on the crosslinked polyamides. For this purpose, trifluoroacetic anhydride was used to protect the amino group of 5‐aminoisophthalic acid, thus generating 5‐(2,2,2‐trifluoroacetamido)isophthalic acid (TFAIA). TFAIA was converted into TFAIAC using oxalyl chloride, which was exploited as a suitable monomer for the synthesis of aromatic polyamides. Amino groups were then set free under basic conditions and the crosslinking was carried out through amino groups present on the polyamide chains with different dianhydrides, isophthaloyl chloride and 2,5‐thiophenedicarboxaldehyde. The synthesis of monomers and polymers was confirmed by Fourier transform infrared, 1 H and 13 C NMR spectroscopy and molar masses of the polyamides were measured by gel permeation chromatography. The crosslinked macromolecules were found to possess enough chain alignment as depicted by their XRD patterns. The thermal stability of the crosslinked polyamides was increased as their decomposition temperatures were improved from 420 to 619 °C. Metal ion uptake was scrutinized through atomic absorption spectroscopy with 83%–85% adsorption capacity at optimized parameters, i.e. a contact time of 3 h at pH 6. The mechanism of adsorption was further investigated through the Freundlich and Langmuir adsorption isotherms. The results reveal that uptake of metal ions followed monolayer adsorption of cations owing to coordination to electronegative centers on the macromolecules, confirming the Langmuir adsorption model. © 2019 Society of Chemical Industry
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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 | 0.000 |
| 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".