Monodisperse, Micron-Sized Reactive Low Molar Mass Polymer Microspheres by Two-Stage Living Radical Dispersion Polymerization of Styrene
Bibliographic record
Abstract
Living/controlled radical dispersion polymerization of styrene was carried out in ethanol and in ethanol−water mixtures in the presence of perfluorohexyl iodide (C 6 F 13 I, 2−5 wt % based on styrene) as a degenerative chain transfer (DCT) agent or 1-cyano-1-methylpropyl dithiobenzoate (CMPDB, 0.5 and 1.0 mol % based on styrene) as a reversible addition−fragmentation chain transfer (RAFT) agent. These reagents disrupt the nucleation stage of particle formation when present at the start of the reaction. If their addition is delayed until the nucleation stage is complete, the reaction acquires the characteristics of a living/controlled radical polymerization: M n increases linearly with the monomer conversion, and the molar mass distribution is much narrower (minimal M w / M n: 1.2) than polystyrene prepared without C 6 F 13 I or CMPDB. For reactions in ethanol, at low molar mass, the particles formed have a broad size distribution as a consequence of the solubility of the polymer at the reaction temperature, followed by precipitation upon cooling. When the reactions were run in a more polar medium (95 wt % aqueous ethanol), the polymer molecules precipitated as they were formed and were absorbed by the existing particles in the solution. The particles formed had an average diameter in the range 1−3 μm with a very narrow size distribution (CV < 1%). The polymer chains in these particles are reactive and chain-extendible.
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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 | 0.001 |
| 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 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".