Evaluation of catalyst leaching in silica supported zirconocene alumino hydride catalysts
Bibliographic record
Abstract
Abstract Zirconocene aluminohydride complexes (e.g. nBuCp2ZrH3AlH2) afford higher MW polyethylene at significantly higher activity than their zirconocene dichloride counterparts (nBuCp2ZrCl2) when activated by methylaluminoxane (MAO). In this work, supported catalysts with different Al:Zr ratios on SiO2, modified with MAO were prepared, and evaluated for their tendency towards leaching in ethylene polymerization, using additional MAO or other alkylaluminum compounds. The extent of catalyst leaching was estimated by comparing kinetic data of filtered versus unfiltered catalysts during ethylene polymerization. Polydispersities and molecular weights of the HDPE obtained using filtered versus unfiltered catalysts were also compared under similar polymerization conditions. Polyethylene morphologies obtained in homogeneous and heterogeneous phase were compared by SEM. Bulk densities of the HDPE were evaluated and related to the leaching in the polymerizations.
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 | 0.001 |
| 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) | 0.000 | 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".