Ultrahigh Molecular Weight Copolymers of Isobutene and 2,3-Dimethyl-1,3-butadiene Formed Using a Novel Protic Carbocationic Initiator, the 1:2 Adduct of <i>n</i>-Octadecanoic (Stearic) Acid and B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>
Bibliographic record
Abstract
Ultrahigh molecular weight copolymers of isobutene (IB) and 2,3-dimethyl-1,3-butadiene (DMBD), analogous to commercial IB−isoprene copolymers, are prepared employing as carbocationic polymerization initiator the highly acidic 1:2 adduct of n -octadecanoic (stearic) acid with the electrophilic borane B(C 6 F 5 ) 3, [ n -C 17 H 35 CO 2 H][B(C 6 F 5 ) 3 ] 2 . High conversions to gel-free, low-polydispersity materials with weight-average molecular weights well in excess of 3 × 10 6 are readily obtained, demonstrating the effectiveness of { n -C 17 H 35 CO 2 [B(C 6 F 5 ) 3 ] 2 } - as a weakly coordinating anion. Complete 1 H and 13 C{ 1 H} NMR assignments for the IB−DMBD copolymers, in which the 1,3-diene is incorporated in a 1,4-trans manner, are presented for the first time.
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 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 | 0.000 |
| 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 | 0.000 |
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".