Surface-functionalized layered double hydroxides (LDHs) nanoplatelets for enhanced thermal stability of plasticized polyvinyl chloride (PVC) films
Bibliographic record
Abstract
• Oleic acid is investigated as a surface modifier for LDH-based PVC stabilizers. • PVC processed with modified LDHs shows enhanced thermal stability. • Oleic acid improves both LDH dispersion and its affinity with the PVC matrix. • PVC degradation and polyene formation are suppressed. Polyvinyl chloride (PVC) is the third most produced plastic globally and a significant contributor to plastic waste. Thermal stabilizers are essential for PVC processing to prevent degradation, a role that becomes even more critical in recycling techniques where repeated reprocessing exacerbates degradation issues. Recent studies have explored layered double hydroxides (LDHs) as promising PVC stabilizers, offering a balance between stabilization efficiency, environmental impact, and cost. However, achieving effective compatibilization with PVC remains a challenge. In this study, we provide mechanistic insights into LDH stabilization by proposing a four-stage reaction mechanism during PVC degradation. This mechanism highlights the roles of interlayer anions, the interactions of basic metal components (Mg, Zn, Al), and the contribution of each element to LDH’s acid-neutralizing capabilities in suppressing HCl release. Raman spectroscopy confirmed that Zn contributes the most to HCl absorption due to its higher electronegativity and affinity for HCl, while Mg exhibits a delayed interaction, and Al contributes at later stages, indicating a progressive role in stabilization. To further enhance LDH stabilization efficiency, we modified LDH by retaining oleic acid (OA) on its surface. The introduction of OA improved LDH-PVC compatibility and enhanced HCl absorption through the reactivity of OA’s C=C bonds under acidic conditions. Unlike stearic acid, OA contributed to neutralization reactions and reinforced PVC stabilization. The OA-modified LDH (MC-9OA) demonstrated more than a twofold increase in static thermal stability compared to unmodified LDH-PVC compounds. These findings highlight both the fundamental stabilization mechanism of LDHs in PVC and the enhancement achieved through OA modification. This dual approach contributes to the sustainability of PVC products by improving their thermal stability, particularly in recycling applications.
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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".