Sustainable Carbon Nanodots with Tunable Radical Scavenging Activity for Elastomers

Abstract

The application of polymers as an essential class of material was greatly inhibited due to the aging failure of these versatile materials during normal use. Hence, it is generally recognized that stabilization against thermo-oxidative aging is indispensable to extend the service life of polymers for long-term applications. However, toxicity and pollution of the state-of-the-art antiaging technologies have long been puzzles in the polymer industry. Herein, sustainable carbon nanodots (CDs), synthesized by facile and cost-effective microwaveassisted pyrolysis, are used for first time as radical scavengers to resist the thermo-oxidative aging of elastomers. We have demonstrated that incorporation of the resultant CDs could be green and generic radical scavengers toward highly aging-resistant elastomers. Furthermore, by controlling the photoluminescent quantum yield of the CDs with various passivated agents, tunable radical scavenging activity was achieved. We established for the first time that the aging resistance originates from the prominent reactive radical scavenging activity of the CDs, which was rationally controlled by their photoluminescent quantum yield.

Influence of Oxidation Level of Graphene Oxide on the Mechanical Performance and Photo-Oxidation Resistance of a Polyamide 6

“…As regards nanocomposites containing GO-1 (Figure 7B), all the carbonyl species are scarcely present in unirradiated samples, likely due to the well-known antioxidant activity of nanocarbons [48,49,50,51], which could have protected the polymer from thermo-oxidative reactions during mixing, in fully agreement with the results of rheological and mechanical tests previously discussed. The build-up of carbonyl domain upon UV-exposure time in this case follows a different pathway, with the signals attributable to conjugated and dimeric carboxylic acids being almost indistinguishable each other but however more intense than those ascribed to imides and ketones.…”

“…In fact, beyond the UV-shielding effect typical of carbonaceous nanofillers, GO-2 somehow hindered the propagation of photochemical reactions even throughout the exposed surface of films. A possible explanation of this multi-level protection may involve several factors: (i) GO-2 was found to absorb more than GO-1 in UV range (see again Figure 2C), thus resulting in a UV-shielding activity, (ii) GO-2 presents a larger amount of cavities, holes (Figure 1) and Stone-Wales defects (detected by Raman spectroscopy, Figure 2A) that are known to act as radical scavengers [49,50], (iii) also the extended chemical interphase may have prevented the propagation of degradation pathways, thus acting as a further barrier.…”

Sustainable rubbers and rubber additives

“…Wu et al . reported the preparation of sustainable carbon nanodots from citric acid via microwave‐assisted pyrolysis method.…”

Hydrophilic Carbon Nanomaterials: Characterisation by Physical, Chemical, and Biological Assays

“…[6][7][8] Despite the benefits that carbon nanomaterials can provide to medicine, their intrinsic therapeutic potential, comingf rom their antioxidant and radical scavenging capabilities in biological systems, has not been extensively investigated. The antioxidant properties of carbon-basedm aterials, such as carbon nanotubes, graphene and graphene oxide, have been broadly recognised, [9][10][11][12][13] although they have only found utility for the protection of polymericm atrices against oxidative degradation, [14][15][16][17] and not in the biomedical field due to their toxicity and low bioavailability. [18,19] Because carbon dots are known to have good water-solubility,b iocompatibility and low cytotoxicity,t hey would be good candidates for therapeutic applicationsi ft hey displayed antioxidant andr adical scavenging capabilities.…”