Characterization of waxes as possible coating material for organic aerogels

Goslinska, M.; Heinrich, Stefan

doi:10.1016/j.powtec.2019.08.096

Cited by 25 publications

(14 citation statements)

References 29 publications

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“…The increase in contact angle as a result of artificial ageing may be a consequence of the decrease of polar groups on the surface of the mock-ups [ 62 , 63 ]. Considering also the translucent appearance of the samples even before the treatments, we can reasonably hypothesize the migration of a part of the waxy fraction present in the binder towards the surface with a resulting decrease of its polarity and therefore an increase of the contact angle [ 57 , 64 ]. Such changes were not detected by FT-IR-ATR, which analyses thicknesses in the order of a few microns [ 65 ], while it is likely that the waxy fraction has a lower thickness.…”

Section: Resultsmentioning

confidence: 99%

Accelerated Ageing Procedures to Assess the Stability of an Unconventional Acrylic-Wax Polymeric Emulsion for Contemporary Art

et al. 2020

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This research evaluates the stability of an aqueous emulsion of acrylic copolymers and waxes. Edelwachs, generally applied on wood, has been recently used as an unconventional medium in contemporary painting. Through Pyrolysis–Gas Chromatography–Mass Spectrometry (Py-GC-MS) and Fourier Transformed Infrared Attenuated Total Reflectance (FT-IR-ATR) analyses, the composition of Edelwachs was defined as a mixture of acrylic polymers (MA, MMA, nBA, nBMA), Carnauba and microcrystalline waxes and additives. Mock-ups-obtained mixing Edelwachs with titanium white, zinc white and ultramarine blue were subjected to UV, high temperatures, and high relative humidity accelerated ageing. The effect of the ageing procedures was evaluated through optical microscopy, colourimetric measurements, FT-IR-ATR, Thermogravimetry and Differential Scanning Calorimetry (TG-DSC) and wettability measures. FT-IR-ATR spectra do not show significant variations in terms of chemical stability, indicating a fair stability of Edelwachs as a painting binder. UV and high temperature treatments show the most relevant effects in terms of colorimetric changes (increasing of b*) and thermal stability. The TG-DSC highlights the influence of the pigments (specifically zinc white) mainly on the thermal behaviour of the acrylates. The unexpected decrease of wettability of the paint films, registered after ageing, may indicate a possible phase separation among acrylates and waxes.

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Section: Resultsmentioning

confidence: 99%

Accelerated Ageing Procedures to Assess the Stability of an Unconventional Acrylic-Wax Polymeric Emulsion for Contemporary Art

et al. 2020

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“…The low‐bond axisymmetric drop shape analysis plug‐in LBDSA in ImageJ was used to analyse the images. The apparent CA represents the angle on a rough surface between the baseline of the apparent solid surface and the tangent on the droplet surface curvature (Goslinska & Heinrich, 2019). The differences in the means of CA were evaluated through ANOVA as a result of the analysis of a model of repeated measures where the effect of two factors (1) time ( t 0 = initial time and six additional times, evaluated every 5 s) and (2) cuticular wax extracted from PPC (CW‐H, CW‐PE, CW‐E, and SCW‐E), which amounted to 140 observations.…”

Section: Methodsmentioning

confidence: 99%

“…In relation to the effects of different storage humidity conditions on mature Korla pear fruit, natural waxes were also analysed to clarify the role of cuticular wax in storage quality and senescence (Wang et al ., 2021). Besides, the potential role of wax components on postharvest quality, beeswax, candelilla wax, rice bran wax, and sunflower wax have been investigated as possible coating materials for organic aerogels regarding their thermic, moisture barrier, and wettability properties (Goslinska & Heinrich, 2019). Even the citrus by‐product lemon wax was examined using a novel application of solid‐phase microextraction‐gas chromatography and ultra‐high performance liquid chromatography (SPME‐GC and UHPLC) to evaluate the possible use of a discarded fraction from citrus fruit processing (Costa et al ., 2019).…”

Section: Introductionmentioning

confidence: 99%

“…One of the most important functions of the cuticle is attributed to its hydrophobic component, wax. Waxes are generally defined as hydrophobic organic substances containing medium and long chains of carbon atoms (Goslinska & Heinrich, 2019). The hydrophobicity of the cuticle reduces non‐stomatal water loss, known as ‘cuticular transpiration’, whereas the cutin polymer provides physical shielding for the plants (Bhanot et al ., 2021).…”

Section: Introductionmentioning

confidence: 99%

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Extraction and characterisation of cuticular waxes from Physalis peruviana calyx

Castellanos,

Rojas‐Pérez

2024

Int J of Food Sci Tech

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SummaryWaxes play an important role in maintaining fruit quality and shelf‐life extension because they are naturally effective in blocking the migration of moisture. In this work, cuticular waxes from Physalis peruviana calyx (PPC) were extracted and characterised as potentially hydrophobic materials. Extraction was carried out using the Soxhlet technique with two non‐polar solvents, hexane and petroleum ether, and one polar solvent, ethanol. The extraction yield, lipid characterisation, and hydrophobic potential of cuticular waxes from PPC were analysed and compared using thin‐layer chromatography (TLC), attenuated total reflectance‐infrared spectroscopy (ATR‐IR), GC–MS chromatogram (FAMES), and wetting contact angle. Extraction using hexane was the most efficient method (yield of 9.61 ± 0.37%) for obtaining cuticular waxes with better hydrophobic properties, characterised by a contact angle of = 107.37 ± 1.0° and a hysteresis contact angle of 11° due mainly to the presence of functional groups desirable and characteristic of vegetable waxes. Greater texture homogeneity visualised using optical microscopy and the presence of capric acid (70.97%) as a major component of low‐molecular‐weight fatty acids were observed in this extract. Due to their biodegradable, potentially antifungal, and hydrophobic properties, cuticular waxes from PPC have the potential to replace synthetic waxes in industrial applications.

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“…Tablets coated with F1 did not display sufficient gastro-resistant properties and disintegrated in <20 min in the gastric medium. Composed of water-insoluble ester and fatty acid [26], waxes can act as a hydrophobic barrier and contribute to the resistance to disintegration in an aqueous environment [27].…”

Section: Acid Uptake and Disintegrationmentioning

confidence: 99%

A Novel Multilayer Natural Coating for Fed-State Gastric Protection

et al. 2022

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Several nutraceutical products require gastric protection against the hostile environment in the stomach. Currently marketed synthetic and semi-synthetic coatings suffer from major shortcomings such as poor gastric protection, slow-release response to pH change, and the use of artificial ingredients. The challenge of coating natural products is further exacerbated by the relatively high gastric pH in the fed state. In this work, a novel natural enteric coating is presented as a breakthrough alternative to current solutions. Two coating systems were devised: (i) a triple-layer coating that comprises a wax layer embedded between two alginate-based coatings, and (ii) a double-layer coating, where an overcoat of organic acids (fumaric or citric acid) is applied to an alginate-based coating. The multi-layer architecture did not impact the pH-responsive nature of the coating even when more biologically relevant Krebs bicarbonate buffer of lower buffer capacity was used. Interestingly, the gastric protection barrier of organic acid-based coating remained resistant at elevated gastric pH 2, 3, or 4 for 2 h. This is the first report of using an alginate-based coating to provide gastric protection against fed-state stomach conditions (pH 2–4). Being biodegradable, naturally occurring, and with no limit on daily intake, the reported novel coating provides a superior platform to current coating solutions for pharmaceutical and nutraceutical products.

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Characterization of waxes as possible coating material for organic aerogels

Cited by 25 publications

References 29 publications

Accelerated Ageing Procedures to Assess the Stability of an Unconventional Acrylic-Wax Polymeric Emulsion for Contemporary Art

Accelerated Ageing Procedures to Assess the Stability of an Unconventional Acrylic-Wax Polymeric Emulsion for Contemporary Art

Extraction and characterisation of cuticular waxes from Physalis peruviana calyx

A Novel Multilayer Natural Coating for Fed-State Gastric Protection

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