"Living"/controlled radical polymerization: From emulsion atom transfer radical polymerization to the synthesis of new nitroxides for stable free radical polymerization
Bibliographic record
Abstract
Emulsion polymerization is an important process for the industrial production of polymers. However, initial attempts at performing "living"/controlled radical polymerization under emulsion conditions were not particularly successful primarily due to latex instability. To address this problem a unique nanoprecipitation process was developed in our laboratory for the stable free radical polymerization (SFRP) process. The first part of this thesis describes attempts to generalize this process and extend it to the copper based atom transfer radical polymerization, ATRP, process. Details describing initial problems we had with reproducing some initial successful results are provided. Once the process was under control it was used to synthesize block copolymers. The ability of these block copolymers to self-assemble in aqueous solutions and in bulk were subsequently investigated and the results of these studies are detailed at the end of the discussion on the emulsion process. The second part of the thesis deals with the SFRP process and more specifically with the difficulty of the process to moderate the polymerization of acrylates. Two reasons have been advanced to account for this difficulty; a high bond dissociation energy between the C-O bond linking the nitroxide moiety to the end of the polymer chain and an accumulation of excess nitroxide, caused by unavoidable chain termination, which causes inhibition of the polymerization. To address the high bond dissociation energy a nitroxide, specifically, 1,1'-diadamantyl nitroxide, containing very bulky substituents that might cause the bond to weaken, was synthesized and studied. To address the accumulation of excess free nitroxide, high temperature additives, that would slowly dissociate over time and consume the excess nitroxides, were studied. The results of both of these approaches are provided enabling some insight into what might be actually restricting the polymerization of acrylates.
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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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".