Mitigating UV-C Degradation in Polypropylene Using Hybrid TiO <sub>2</sub> /Few-Layer Graphene/Photostabilizer Systems
Why this work is in the frame
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Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide Polypropylene (PP) is a versatile thermoplastic widely used in industrial fields. In medical devices, PP is preferred for applications that involve storing or coming into contact with biological fluids. However, when exposed to UV-C, commonly used as a cleansing tool in hospitals, PP undergoes a photodegradation process, resulting in chain scissions and branching reactions that impact the material properties and lifespan. Different photostabilizers can be used to enhance polymer resistance against UV, such as UV screeners like titanium dioxide rutile (TiO 2 ), radical scavengers like Irganox B215, a commercial H-donor and peroxide scavenger, and, more recently, graphene and its derivatives like few-layer graphene (FLG). Graphene has gained attention as an alternative photostabilizer in polymers for having different types of UV photoprotection mechanisms, such as UV absorbers/screeners and radical scavengers. In this context, this study aimed to evaluate the effectiveness of FLG and Irganox B215 as radical scavengers in combination with TiO 2 to minimize the effect of parallel radical formation (ROS) from TiO 2 electron–hole reactions and from the PP photodegradation autocatalytic cycle. A Design of Experiments (DoE) approach was employed to identify the optimal UV-C photostabilization mixture. Infrared spectroscopy and rheological measurements were used to assess the effects of UV-C photodegradation on PP. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to analyze the stabilizer distribution and dispersion, and electron paramagnetic resonance evaluate the effectiveness of FLG and Irganox B215 as radical scavengers. EPR results showed that mixing radical scavengers with TiO 2 reduced OH formation by ∼30% for the FLG and ∼25% for the B215 mixture. Although the stabilizers exhibited poor dispersion but good distribution, the addition of FLG had a synergistic effect with TiO 2 . At the highest level (+1), i.e., TiO 2 3% and FLG 2% m/m, PP UV–C photoprotection was enhanced by diminishing chain scission and scavenging ROS from TiO 2 .
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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 it