Effect of Ligand Spacer on Silica Gel Supported Atom Transfer Radical Polymerization of Methyl Methacrylate
Bibliographic record
Abstract
Silica gels grafted with tetraethyldiethylenetriamine (TEDETA) and di(2-picolyl)amine (DiPA) via poly(ethylene glycol) (PEG) spacers of different chain lengths were synthesized and used as CuBr support for the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA). The spacer length strongly affected the polymerization rate and polymer molecular weight control. Catalyzed by CuBr immobilized on the silica gel, the MMA polymerization rate increased with spacer length in the order of PEG 1 < PEG 10 < PEG 3 (the subscript is the number of the EG units). Copper bromide supported via three-unit PEG (SG-PEG 3 -TEDETA and SG-PEG 3 -DiPA) controlled the MMA polymerization best, producing PMMA with controlled molecular weights (initiator efficiency ca. 75%) and low polydispersities ( M w / M n ∼ 1.2−1.4). The recycled catalysts had activities similar to the fresh ones at the late stage of polymerization with improved initiator efficiencies. The PMMA- block -poly(2-( N,N -dimethylamino)ethyl methacrylate) with well-controlled molecular weight and low polydispersity was also synthesized by this support system.
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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) | 0.000 | 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".