Heterogeneous Atom Transfer Radical Polymerization of Methyl Methacrylate at Low Metal Salt Concentrations
Bibliographic record
Abstract
The heterogeneous atom transfer radical polymerization of methyl methacrylate using the catalyst complex CuBr/1,1,4,7,10,10-hexamethyltriethylene tetramine (CuBr/HMTETA) was undertaken under a number of conditions to elucidate the effects of key process variables. It was found that a 100-fold reduction in metal salt concentration, to 21 ppm in solution (metal to intiator = 0.01:1), reduced polymerization rates 3-fold. PMMA produced at these low concentrations had high initiator efficiencies ( I eff = 88%) and low polydispersisties (1.1). Decreasing metal salt concentrations 1000-fold, to 2 ppm (Mt:I = 0.001:1), resulted in PMMA with controlled molecular weights ( I eff = 96%) but high polydispersities (2.1). Polymerization rates above and below a metal concentration of 210 ppm were found to be proportional to the metal salt concentration to the power of 0.05 and 0.37, respectively. Rates were found to increase with ligand concentration to the power of 0.52. Stirring was found to increase polymerization rates by 40%.
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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) | 0.000 | 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 | 0.001 |
| 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".