PLP-SEC Investigation of the Influence of Electrostatic Interactions on the Radical Propagation Rate Coefficients of Cationic Monomers TMAEMC and MAPTAC
Bibliographic record
Abstract
The decisive role of counterions on the propagation mechanism in the radical polymerization of ionized monomers is comprehensively studied. Propagation rate coefficients, k p, were obtained for cationic monomers [2-(methacryloyloxyethyl)]trimethylammonium chloride (TMAEMC) and [3-(methacryloylaminopropyl)]trimethylammonium chloride (MAPTAC) in aqueous solution by pulsed-laser polymerization combined with size-exclusion chromatography over broad ranges of monomer concentration (1–40 wt %), temperature (5–90 °C), pH (2–12), and salts selected to provide a molar counterion concentration, c counterion, between 0.05 and 3 mol·L –1 . Both monomers behave similarly under conditions at which repulsive electrostatic interactions between a polymer chain and a reacting monomer dominate ( c counterion < 0.2 mol·L –1 ). The k p values increase linearly with c counterion above this value due to screening of the repulsive interactions and follow the family behavior of nonionized methacrylate and methacrylamide monomers manifested by a higher k p for TMAEMC than for MAPTAC. The hydration of the polyelectrolyte chain is considered as an additional factor contributing to higher k p values for cationic TMAEMC at high c counterion values compared to its nonionized analogue 2-dimethylaminoethyl methacrylate. The extensive set of k p data can be represented using average activation energies of 14.4 ± 2.7 and 14.7 ± 2.0 kJ·mol –1 for TMAEMC and MAPTAC, respectively, and a preexponential factor that increases with c counterion . The batch polymerization of MAPTAC compared to that of TMAEMC reflects the differences in k p behavior for these monomers.
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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 | 0.001 |
| 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 | 0.001 |
| 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".