Mass Transport Limitations and Their Effect on the Control of the Molecular Weight Distribution in Catalytic Chain Transfer Mediated Emulsion Polymerization
Bibliographic record
Abstract
The existence of mass transport limitations in catalytic chain transfer mediated emulsion polymerization of methyl methacrylate (MMA) using bis[(difluoroboryl)dimethylglyoximato]cobalt(II) (COBF) was investigated. The rate of mass transport of COBF from the aqueous phase toward the polymer particles proved to depend strongly on the viscosity of the polymer particles and consequently on the instantaneous conversion. At high instantaneous conversion the exchange of COBF between the particles and the aqueous phase is severely hindered. As a result, the control of the molecular weight distribution is hampered. At low instantaneous conversion COBF is readily transferred between the aqueous phase and polymer particles, resulting in immediate molecular weight control. The chain transfer activity of COBF inside the polymer particles during the polymerization was successfully quantified using the chain length distribution method. The results of this work show that the presence of a catalytic chain transfer agent can severely affect the course of the emulsion polymerization. Furthermore, it was demonstrated that molecular weight control during the final stages of an emulsion polymerization is affected by the increasing viscosity of the polymer particles.
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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 | 0.001 | 0.002 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".