Crystallinity development in cellular poly(lactic acid) in the presence of supercritical carbon dioxide
Bibliographic record
Abstract
Abstract This article investigates the crystallinity development in cellular poly(lactic acid) (PLA) and the effect of the achieved crystalline content on its properties and microstructure. Carbon dioxide (CO 2 ) in its supercritical state was used as the expansion agent for three different grades of PLA that differed in terms of L ‐lactic acid content. Cellular PLA was produced on a twin‐screw extrusion line using capillary dies of various diameters. The obtained crystalline contents were measured by differential scanning calorimetry and X‐ray diffraction techniques. The morphology of the cellular structures was examined using scanning electron microscopy. The crystallinity developed on expansion depended on L ‐lactic acid content, on supercritical CO 2 concentration, polymer flow rate, and die diameter. Cellular PLA, with densities as low as 30 kg/m 3 , was obtained under the most favorable conditions. It was shown that the crystallinity development in PLA enhances its cellular structure formation and enables the fabrication of quality cellular materials at lower CO 2 concentration. The presence of PLA crystallites within expanded cell walls leads to a peculiar 2D‐cavitation phenomena observed only in the cell walls of semicrystalline foams. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
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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 | 0.000 |
| 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".