Sealability and Seal Characteristics of PE/EVA and PLA/PCL Blends
Bibliographic record
Abstract
Abstract Seal strength behavior of low density polyethylene and ethylene vinyl acetate copolymer (PE/EVA) blends as well as that of blends of a seal grade PLA with aliphatic polyester (PCL) was studied. Polyethylene is commonly used for seal application in packaging multilayer structures and amorphous PLA is considered to be its counterpart for compostable and/or biodegradables ones. Incorporation of EVA in polyethylene improves its sealability in terms of a decrease in seal initiation temperature and broadness of sealability plateau. This was interpreted as due to the formation of finer crystals, a decrease in the melting point and presence of vinyl acetate polar group. These were supported by results obtained from differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). For the PLA/PCL system, the dispersed phase was stretched into elongated ellipsoidal domains. This type of morphology affected the mechanical and seal properties of the blends. As a result of blending, both hot-tack initiation temperature and strength as well as seal initiation temperature were enhanced. The enhancement in these seal properties was significant when the concentration of the dispersed phase exceeded 20 wt% in the blend. Hot-tack strength of up to twice of pure PLA was achieved through blending. This was attributed to the lower glass transition temperature of PCL, resulting in enhanced mobility of PLA chains and also the high aspect ratio of the dispersed phase. The maximum obtained hot-tack strength (1 200 g/25 mm) at 40 % dispersed content compared advantageously to commercially available polyolefin based sealant resins. The seal and hot-tack initiation temperatures were shifted to lower temperatures by as much as 30 °C, which can allow faster and more energy efficient sealing process.
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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 | 0.001 | 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".