Effects of irradiation in combination with waxing on the essential oils in orange peel

The study evaluated the effects of waxing, irradiation dose and post‐irradiation storage time on the essential oils in orange peel. Mature oranges (Maroc late) waxed or unwaxed were treated with 1 or 2 kGy radiation and stored for 9 weeks at 20 °C and 40–50% RH. Essential oils from the peel were extracted and analysed by GC. Results showed that D ‐limonene was significantly lower in waxed oranges; levels in samples treated with 2 kGy were higher than those in non‐irradiated or treated with 1 kGy. Linalool, methyl anthranilate and 3,7‐dimethyl‐2,6‐octadienal decreased as the dose increased. Levels of linalool increased with storage time but D ‐limonene was unaffected. These results may aid in guaranteeing the quality of orange essential oils during storage time. Copyright © 2004 Society of Chemical Industry     

Degradation of Polycarbonate Properties Under Thermal Aging

Journal of Failure Analysis and Prevention - The aim of this paper is to characterize the thermal aging effect near the glass transition temperature of polycarbonate (PC) at different hold time....     

Interfacial damage on fatigue‐loaded textile–rubber composites

To reach admissible lifetime expectancy, unidirectional textile–rubber composites must show a strong interface. Usually, it is achieved by coating the textile with Resorcinol–Formaldehyde–Latex (RFL). To evaluate fatigue impact on interfacial properties, composites with or without RFL are tested at different numbers of loading cycles and characterized through peel tests, dynamic mechanical analysis (DMA), scanning electron microscopy and energy‐dispersive X‐rays, and nanoindentation. For composites with RFL, the results indicate two main mechanisms for damaging: propagation of pre‐existing fibrillar microcracks at the rubber/RFL interface completed by adhesive debondings at the RFL/textile interface. At first, the propagation of fibrillar microcracks is correlated with decrease of global composite peeling resistance and contribution of interphase to DMA damping. Then, RFL/textile debondings become critical. They are highlighted with a change of peeling failure surface and could be explained by RFL hardening, highlighted by nanoindentation. This questions the choice for RFL as a sustainable adhesive for composites under fatigue loading. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41346.     

Phenolic compounds and the colour of oranges subjected to a combination treatment of waxing and irradiation

The effects of waxing, irradiation doses and storage on phenolic compounds and colour of irradiated oranges were investigated. Mature oranges (Citrus sinensis (L) Osbeck var Maroc late) waxed or unwaxed were treated with 0, 1 or 2 kGy radiation and stored up to 9 weeks at 20 °C and 40–50% RH. Colour of the oranges, total phenols and flavones in the peel were measured. Phenolic compounds increased with irradiation dose and storage time. Hue angle, L* value and chroma of the orange colour were more affected by waxing and storage time than the irradiation treatment. Changes in the phenolic compounds were linked with changes in the redness and saturation of the orange colour. Irradiation stimulated synthesis of flavones; waxing controlled changes induced by irradiation. These results may aid in maintaining the quality and safety of oranges during storage. Copyright © 2004 Society of Chemical Industry     

Repair and Restoration of the Optical Properties of Sandblasted Glasses By Silica-Based Sol-Gel Coatings

The damage provoked by sand storms in Sahara desert to windscreen of vehicles and solar mirrors is a problem. Different solutions have been proposed, one of them is the application of polymeric coatings, but they rapidly degrade. In this work, we have deposited silica-based sol-gel coatings including silica nanoparticles onto sandblasted glasses. The glasses were eroded by sandblasting varying the projected sand mass and the incidence angle to obtain different surface states. The eroded samples were coated by dipping with a silica layer to correct the defects induced by sandblasting and restore the optical transmission. The damage increases with increasing projected mass and the impact angle. The optical transmission decreases with increasing damage. In extreme conditions, optical transmission falls from 91.5% to 68.6%. The deposition of silica-based layers containing SiO₂ colloidal nanoparticles promotes the repairing of sandblasting defects. A strong decrease of roughness to values similar to those of as-received glass is related with the increasing of the optical transmission up to levels permitting of windscreens and solar mirrors. Transmittance measurements showed a remarkable improvement in all cases, whatever the projected sand mass or the impact angle. For highly degraded samples, the transmission increases from 68.6% to 91.4%, an improvement of near 23%.