Kinetics and Modeling of Semi-Batch RAFT Copolymerization with Hyperbranching
Bibliographic record
Abstract
This work reports a kinetic model developed to provide insight into branching mechanisms and control of gelation by semibatch controlled radical copolymerization processes. The semibatch RAFT copolymerization of acrylamide (AM) and N, N ′-methylenebis(acrylamide) (BisAM) in the presence of 3-benzyltrithiocarbonyl propionic acid (BCPA) as chain transfer agent (CTA) was carried out for the model validation. The BisAM was fed to the reactor at a constant rate to yield hyperbranched polyacrylamide (b-PAM) without gelation. Different feeding rates and [BisAM] 0 /[CTA] 0 ratios were theoretically simulated and experimentally investigated to optimize the instantaneous BisAM concentration in the reactor for branching formations. No gel was formed in the semibatch operation up to 99% total monomer conversion, in contrast to gel occurrence at 70% conversion in its corresponding batch operation. The polymer molecular weight and polydispersity as well as branching density increased slowly throughout the semibatch polymerization. Cyclization reactions were significant and helped to suppress the gelation. The model simulations correlated the experimental data very well.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".