Rheological Comparison of Chemical and Physical Blowing Agents in a Thermoplastic Polyolefin
Bibliographic record
Abstract
The influences of popular blowing agents (BAs), both chemical and physical types, in solution with a thermoplastic polyolefin (TPO) were investigated with an in-line capillary rheometer nozzle attached to a conventional reciprocating 55-ton injection molding machine. In the experiments, two types of masterbatch chemical BAs (endothermic and exothermic type) were dry mixed with the TPO resin and compared against two types of physical BAs (carbon dioxide and nitrogen) directly injected into a specially designed injection nozzle containing static mixer elements (SMX type). The effects of the main processing conditions (injection speed, pressure, temperature, and BA type and concentration) on the TPO melt rheology were studied. The viscosity reduction behaviors of chemical BAs and physical BAs were compared. The type of BA had a strong influence on the viscosity reduction behavior of the TPO melt, with the maximum viscosity reduction of 47% with 3.2 wt % CO 2 at 250 °C. Both physical and chemical BAs were found to successfully fit a previously developed viscosity model for single-phase gas−polymer solutions.
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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 | 0.001 |
| 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) | 0.001 | 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".