Strategies for achieving ultra low‐density polypropylene foams
Bibliographic record
Abstract
Abstract The volume expansion behavior of low‐density polypropylene foams in extrusion is investigated in this paper. Since escape of blowing agent from the foam would cause the foam to contract, and to have low expansion, efforts were made to prevent gas loss during foaming. The basic strategies to the promotion of a large volume expansion ratio are: to use a branched material for preventing cell coalescence; to use a long‐chain blowing agent with low diffusivity; to lower the melt temperature for decreasing gas loss during expansion; and to optimize the processing conditions in the die for avoiding too‐rapid crystallization. Use of a branched polypropylene resin was required to achieve large volume expansion because prevention of cell coalescence will retard gas loss from the extruded foam to the environment. The foam morphologies of linear and branched polypropylene materials at various processing temperatures were studied using a single‐screw tandem foam extrusion system and their volume expansion behaviors were compared. Ultra lowdensity, fine‐celled polypropylene foams with very high expansion ratio up to 90 fold were successfully produced from the branched polypropylene resins.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| 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".