Nitroxide‐mediated synthesis of styrenic‐based segmented and tapered block copolymers using poly(lactide)‐functionalized TEMPO macromediators
Bibliographic record
Abstract
Abstract Poly(styrene)‐poly(lactide) (PS‐PLA), poly ( tert ‐butyl styrene)‐poly(lactide) (P t BuS‐PLA) diblocks, and poly( tert ‐butyl styrene)‐poly(styrene)‐poly(lactide) (P t BuS‐PS‐PLA) segmented and tapered triblocks of controlled segment lengths were synthesized using nitroxide‐mediated controlled radical polymerization. Well‐defined PLA‐functionalized macromediators derived from hydroxyl terminated TEMPO (PLA T ) of various molecular weights mediated polymerizations of the styrenic monomers in bulk and in dimethylformamide (DMF) solution at 120–130°C. PS‐PLA and P t BuS‐PLA diblocks were characterized by narrow molecular weight distributions (polydispersity index ( M w / M n ) < 1.3) when using the PLA T mediator with the lowest number average molecular weight M n = 6.1 kg/mol while broader molecular weight distributions were exhibited ( M w / M n = 1.47‐1.65) when using higher molecular weight mediators ( M n = 7.4 kg/mol and 11.3 kg/mol). Segmented P t BuS‐PS‐PLA triblocks were initiated cleanly from P t BuS‐PLA diblocks although polymerizations were very rapid with PS segments ∼ 5–10 kg/mol added within 3–10 min of polymerization at 130°C in 50 wt % DMF solution. Tapering from the P t BuS to the PS segment in semibatch mode at a lower temperature of 120°C and in 50 wt % DMF solution was effective in incorporating a short random segment of P t BuS‐ ran ‐PS while maintaining a relatively narrow monomodal molecular weight distribution ( M w / M n ≈ 1.5). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| 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 | 0.000 |
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".