Surface‐directed morphology evolution in ternary blends of polyethylene, polypropylene, and ethylene–propylene copolymer: A study by laser scanning confocal fluorescence microscopy
Bibliographic record
Abstract
Abstract With laser scanning confocal fluorescence microscopy, we demonstrate a novel type of morphology evolution in moderately thick films (70–100 μm) of ternary blends of polypropylene (PP), polyethylene (PE), and ethylene–propylene rubber (EPR), in which EPR is labeled with a benzothioxanthene dye (HY‐EPR). The blends are prepared by solution blending, and the phase morphology evolves during the annealing of the blend films in a stainless steel mold. Our results indicate that wetting of the mold surface is a driving force in morphology evolution for the two blend compositions investigated. For 81/14/5 PP/PE/HY‐EPR, phase evolution within the mold results in a laminar structure and hydrodynamic channels, features which have previously been found in thin films of polymer blends as a result of surface‐directed spinodal decomposition. In a blend with a lower weight fraction of the dispersed phase (92/7/1 PP/PE/HY‐EPR), we find that the PE/HY‐EPR domains are larger and more polydisperse closer to the surface because of wetting of the mold wall. We also show that the phase morphology in these films can be controlled by the nature of one or both of the surfaces being varied. When one of the mold surfaces is replaced with a thin film of PP homopolymer, we observe draining of PE/HY‐EPR from the PP to the mold surface, which results in a bilayer structure. A trilayer morphology is likewise obtained by the replacement of both mold surfaces with PP. We also carry out three‐dimensional image reconstruction on a single PE/HY‐EPR particle within the 81/14/5 PP/PE/HY‐EPR blend to obtain detailed information on the interphase structure. We find that HY‐EPR of this composition (30/70 ethylene/propylene) fully coats the PE dispersed phase and partially penetrates the PE droplets. This result falls between the interphase structures found for previously investigated EPR compositions (40/60 and 80/20 ethylene/propylene). © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 637–654, 2003
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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".