Ethylene Polymerization Kinetics and Microstructure of Polyethylenes Made with Supported Metallocene Catalysts
Bibliographic record
Abstract
The microstructure of polyolefins made with a metallocene supported on a porous carrier is generally less homogeneous than when the polyolefin is made with the same unsupported metallocene. For instance, the molecular weight and chemical composition distributions of ethylene/1-olefin copolymers are often broader when they are made with a supported metallocene. In this article, a mathematical model is used to quantify this phenomenon. The polymerization of ethylene was investigated in parallel semi-batch reactors using a metallocene catalyst supported on an inorganic porous carrier. Ethylene pressure, polymerization temperature, and H2 concentration were the factors changed to study ethylene polymerization kinetics with this catalyst system. Modeling results showed that a three-site model was needed to describe the molecular weight distributions of the polyethylene samples made with this catalyst.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".