Synthesis of rod copolyaramids with short flexible spacers
Bibliographic record
Abstract
Abstract Regular rigid‐flexible copolymers composed of aramid segments and aliphatic chains formed of 5 to 10 CH 2 groups were synthesized using a two‐stage procedure. A first stage consisted of synthesizing, under Yamasaki–Higashi phosphorylation conditions, poly(paraphenylene terephthalamide) blocks or macromonomers of different lengths by using an excess of phenylene diamine. These macromonomers, with functionalized amine extremities, were reacted in a second stage, using the Higashi phosphorylation conditions, with a terephthalic‐acid end‐capped aliphatic amine. Macromonomer molecular weights and polydispersities were estimated from viscosity and NMR measurements, whereas for block copolymers viscosity measurements and size exclusion chromatography of allylated derivatives were performed. Block polydispersity increased with increasing length of block, but remained below 1.6. Copolymers were found to have M w values from 2500 to 8600 g mol −1 , depending on block length and aliphatic chain used. Polydispersity indices were systematically higher for block copolymers than for macromonomers, with values ranging from 1.6 to 4.7. M v and M w were found to be comparable for all copolyaramids, which indicates that addition of short aliphatic chains had a negligible effect on Mark–Houwink parameters. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5098–5112, 2004
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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) | 0.002 | 0.001 |
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".