Peroxide‐controlled degradation of polypropylene using a tetra‐functional initiator
Bibliographic record
Abstract
Abstract The purpose of this work is to evaluate a new tetra‐functional peroxide initiator and offer comparisons with a di‐functional peroxide commonly used in the production of controlled‐rheology polypropylene (CRPP) resins. CRPP resins have been produced by reactive processing in a batch mixer by using various equivalent amounts of a tetra‐functional and a conventional di‐functional peroxide at two different temperatures. At a lower processing temperature (200°C), the chain length of CRPP decreases with increasing initiator concentration of the di‐functional initiator, while in the case of tetra‐functional initiator system, the change of chain length is larger than that in the di‐functional initiator system. At a higher temperature (230°C), the observation is reversed. The molecular weight reduction increases with initiator concentration level for the tetra‐functional initiator, while the di‐functional initiator causes larger reduction in the molecular weight without any obvious relation to the initiator concentration level. Rheological measurements show results consistent with those from gel permeation chromatography (GPC). The observations are explained based on the competition between chain scission and chain extension caused by the single and multiple radicals generated from the initiators. No evidence of architectural change in the CRPP molecules such as branching and crosslinking has been observed in both GPC and rheological measurements. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
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".