Preparation of ultrahigh‐molecular‐weight polyethylene/carbon nanotube nanocomposites with a Ziegler–Natta catalytic system and investigation of their thermal and mechanical properties
Bibliographic record
Abstract
Abstract In this research, ultrahigh‐molecular‐weight polyethylene (UHMWPE)/multiwalled carbon nanotube (MWCNT) nanocomposites with different nanotube concentrations (0.5, 1.5, 2.5, and 3.5 wt %) were prepared via in situ polymerization with a novel, bisupported Ziegler–Natta catalytic system. Magnesium ethoxide [Mg(OEt)2] and surface‐functionalized MWCNTs were used as the support of the catalyst. Titanium tetrachloride (TiCl4) accompanied by triethylaluminum constituted the Ziegler–Natta catalytic system. Preparation of the catalyst and the polymerization were carried out in the slurry phase under an argon atmosphere. Support of the catalyst on the MWCNTs was investigated with Fourier transform infrared spectroscopy. The results confirmed the interaction between the catalyst and the MWCNT hydroxyl groups. Intrinsic viscosity measurements showed an ultrahigh molecular weight in the produced samples. Scanning electron microscopy images confirmed the good dispersion of MWCNTs throughout the polyethylene (PE) matrix. The crystallization behavior of the samples was examined with differential scanning calorimetry. Its results showed that the crystal content of the samples increased with increasing MWCNT concentration up to 1.5 wt %. The same trend was observed for the crystallization temperature, whereas the melting temperature did not change with increasing MWCNT concentration up to 1.5 wt %, but it decreased beyond this concentration. In addition, thermogravimetric analysis results showed that the addition of MWCNTs noticeably improved all of the investigated thermal stability factors of the UHMWPE/MWCNT nanocomposites compared to those of pure PE. The results obtained from tensile testing revealed significant increases in the Young's modulus, yield stress, and ultimate tensile strength. This indicated a tremendous improvement in the mechanical properties of the PE/MWCNT nanocomposites compared to those of pure PE. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci 125:453–461, 2012
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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) | 0.000 | 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".