Long Chain Branching in Ethylene/Propylene Solution Polymerization Using Constrained Geometry Catalyst
Bibliographic record
Abstract
Ethylene (E)/propylene (P) solution copolymerizations with low propylene ratios were carried out using constrained geometry catalyst, [C 5 Me 4 (SiMe 2 N t Bu)]TiMe 2 (CGC), and ansa -zirconocene, rac -Et(Ind) 2 ZrCl 2 (EBI), at 130−150 °C and 3.45 × 10 3 kPa. Ethylene/propylene copolymers with long chain branch (LCB) densities from 0.30 to 0.96 carbons per 10 000 carbons, molecular weight distributions close to 2, and narrow comonomer composition distributions were synthesized with CGC. Broad molecular weight and comonomer composition distributions were found in the EBI copolymers. Reactivity ratios showed that CGC was more active for propylene incorporation than EBI. Terminal group analysis indicated that more terminal unsaturation occurred with EBI than with CGC. Two additional types of terminal unsaturated groups, vinylidene with side group having more than three carbons ( 2VD ) and trans-vinylene ( VE ), were found with EBI while the terminal vinyl ( V ) and vinylidene with methyl side group ( 1VD ) were determined in both CGC and EBI copolymers. Long chain branch structures were formed by the V type macromonomer incorporation. The long chain branching rate constants were also estimated.
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.017 | 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".