Thermo-oxidative resistant nanocomposites containing novel hybrid-nanoparticles based on natural polyphenol and carbon nanotubes

TitleThermo-oxidative resistant nanocomposites containing novel hybrid-nanoparticles based on natural polyphenol and carbon nanotubes
Publication TypeJournal Article
Year of Publication2015
AuthorsArrigo, R, Dintcheva, NT, Guenzi, M, Gambarotti, C, Filippone, G, Coiai, S, Carroccio, S
JournalPolymer Degradation and Stability
Volume115
Pagination129 - 137
Date Published2015
ISBN Number01413910 (ISSN)
Keywordscarbon, Carbon films, Flavonoids, Functional groups, Linear viscoelasticity, molecular weight, Molecules, Morphological observations, Multi-walled carbon nanotubes, Multiwalled carbon nanotubes (MWCN), Nanocomposite films, Nanocomposites, Nanoparticles, Nonmetallic matrix composites, Oxidation, Oxidation resistance, Phenols, Physical interactions, Polyethylenes, Quercetin, Radical scavenging activity, Rheological behaviour, Stress relaxation, Stress relaxation tests, Testing, Thermo-oxidation resistance, Thermo-oxidative stability, Thermogravimetric analysis, Ultra-high molecular weight polyethylene (UHMWPE), Ultrahigh molecular weight polyethylenes, Yarn
Abstract

Quercetin (Q), a natural antioxidant molecule, is physically immobilized onto multi-walled carbon nanotubes (CNTs) bearing covalently-linked long-chain alkyl functional groups, and the so obtained hybrid-nanoparticles are used to prepare Ultra High Molecular Weight PolyEthylene-based nanocomposite films with enhanced thermo-oxidation resistance. The effective immobilization of the Q molecules is confirmed by spectroscopic (micro-Raman, ATR-FTIR, and FTIR) and thermo-gravimetric analyses, and the influence of the nanoparticles on the rheological behaviour and thermo-oxidative stability of the nanocomposites are investigated. Rheological analyses (linear viscoelasticity and stress relaxation tests) and morphological observations reveal that the Q-functionalized CNTs disperse better than bare CNTs in the host matrix. Quercetin confirms to be an excellent anti-oxidant for polyethylene, but the study of the thermo-oxidation behaviour shows that a remarkable stabilizing action only emerges when Q is physically immobilized on the CNTs. In particular, a ten-fold increase of the onset of degradation phenomena in thermo-oxidative environment was found. Such an excellent result is due to a synergic effect stemming from the physical interaction between Q and CNTs, which cannot provide a similar stabilizing action if used separately. In particular, we argue that the process of physical immobilization of the Q molecules causes the formation of structural defects onto outer CNTs surfaces, thus remarkably improving the CNTs radical scavenging activity and probably promoting Q regeneration. In addition, CNTs seem acting as efficient nano-carriers for the quercetin molecules, improving the dispersion of the latter in the host matrix in spite of their poor solubility. © 2015 Elsevier Ltd. All rights reserved.

Short TitlePolym Degradation Stab