Molecular Weight Distribution of Ethylene/1‐Olefin Copolymers: Generalized Bimodality Criterion
Bibliographic record
Abstract
Two single‐site‐type metallocene catalysts can be combined to produce polymers with well‐controlled and broad molecular weight distributions (MWD). As polyolefins with unimodal and bimodal MWDs have different mechanical and rheological properties, a criterion to determine whether a system of two single‐site‐type catalysts produces polymers with unimodal or bimodal distributions is useful for product development and property optimization. In this work, a generalized MWD bimodality criterion is developed and represented as a comprehensive 3D map. The proposed criterion is validated with both simulated and previously reported experimental data. The effect of number average chain length and mass fraction on MWD bimodality criteria are also examined. The results show that unimodal MWDs are more likely to be observed when the mass fraction of one of the copolymers is much higher than the other and when both copolymers have similar average chain lengths. image
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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".