Effect of the addition of inert or TEMPO‐capped prepolymer on polymerization rate and molecular weight development in the nitroxide‐mediated radical polymerization of styrene
Bibliographic record
Abstract
Abstract The importance of diffusion‐controlled (DC) effects on controlled radical polymerization (CRP) processes has been rather controversial and usually considered only if there is some mismatch between experimental data and model predictions of polymerization rate and molecular weight averages. Results from an experimental study designed to create conditions in which DC effects may be present from the outset for the bimolecular nitroxide‐mediated radical polymerization (NMRP) of styrene in the presence of 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) and dibenzoyl peroxide (BPO), are presented herein. The experiments consisted of adding size exclusion chromatography (SEC) polystyrene (PS) standards or nitroxyl‐capped PS (of different molecular weights, in several proportions), to a conventional recipe of bimolecular NMRP of styrene, and studying the effect of their presence on polymerization rate and molecular weight development. A previously developed kinetic model for NMRP of styrene was modified to take into account the presence of prepolymer as an inert “solvent,” or as a monomolecular “controller” of high molecular weight. The effects of DC reactions (propagation, termination, activation, and deactivation of polymer radicals) were modeled using conventional free‐volume theory. Reasonably, good agreement between experimental data and model predictions with either modeling approach was obtained. It was concluded that DC effects are weak in the NMRP of styrene, even in the presence of prepolymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
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How this classification was reachedexpand
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 teacher head, 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".