Effect of acrylic acid neutralization on ‘livingness’ of poly[styrene‐<i>ran</i>‐(acrylic acid)] macro‐initiators for nitroxide‐mediated polymerization of styrene
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Bibliographic record
Abstract
Abstract BACKGROUND: The effect of acrylic acid neutralization on the degradation of alkoxyamine initiators for nitroxide‐mediated polymerization (NMP) was studied using styrene/acrylic acid and styrene/sodium acrylate random copolymers (20 mol% initial acrylate feed concentration) as macro‐initiators. The random copolymers were re‐initiated with fresh styrene in 1,4‐dioxane at 110 °C at SG1 mediator/BlocBuilder ® unimolecular initiator ratios of 5 and 10 mol%. RESULTS: The value of k p K ( k p = propagation rate constant, K = equilibrium constant) was not significantly different for styrene/acrylic acid and styrene/sodium acrylate compositions at 110 °C ( k p K = 2.4 × 10 −6 –4.6 × 10 −6 s −1 ) and agreed closely with that for styrene homopolymerization at the same conditions ( k p K = 2.7 × 10 −6 –3.0 × 10 −6 s −1 ). All random copolymers had monomodal, narrow molecular weight distributions (polydispersity index M̄ w / M̄ n = 1.10–1.22) with similar number‐average molecular weights M̄ n = 19.3–22.1 kg mol −1 . Re‐initiation of styrene/acrylic acid random copolymers with styrene resulted in block copolymers with broader molecular weight distributions ( M̄ w / M̄ n = 1.37–2.04) compared to chains re‐initiated by styrene/sodium acrylate random copolymers ( M̄ w / M̄ n = 1.33). CONCLUSIONS: Acrylic acid degradation of the alkoxyamines was prevented by neutralization of acrylic acid and allowed more SG1‐terminated chains to re‐initiate the polymerization of a second styrenic block by NMP. Copyright © 2008 Society of Chemical Industry
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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) | 0.001 | 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) | 0.001 | 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