Search Results (3)

To enhance the interfacial adhesion between poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) film and functional coatings, such as silver (Ag) coating, among others, the surface activation of FEP film has to be performed. Among various activation strategies, chemical activation, such as using naphthalene sodium system, is one of the most efficient methods. However, the effect of chemical activation on the interface interaction between the activated FEP and functional coating is rarely investigated. Herein, the FEP film was activated by naphthalene sodium solution under different conditions, and then the Ag layer was coated onto its surface by vacuum Ag deposition. Based on experimental results and density function theory (DFT) calculation, it is indicated that oxygen-containing functional groups (such as C=O and C–OH groups), introduced onto the surface of FEP by the chemical activation, play a key role in boosting the interface interaction, which is due to the strong interaction between the oxygen-containing functional groups and Ag atoms. In addition, the concentration of naphthalene sodium solution, activation time, and winding speed of Ag- deposition can have a significant impact on the microstructures of Ag coating and the interfacial adhesion between the activated FEP and Ag coating. Under the conditions of high concentration (0.9 M), medium activation time (15 min), and high winding speed (0.8 m min⁻¹), there is the best interface adhesion. Full article

Due to their low surface energy, poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) films must be treated by chemical or physical activation methods before using. Among these activation strategies, using sodium naphthalene solution is a popular one. However, the effect of this strategy’s chemical activation conditions on the surface properties of the FEP film is rarely discussed. In this study, FEP films were chemically activated by the sodium naphthalene solution with adjusting concentration, solvent, and activation time. With increasing concentration and activation time, many granular substances appeared on the surface of the FEP film. When tetrahydrofuran was used as a solvent, the color of the film gradually turned brown; when 1,3-dimethyl-2-imidazolidinone was chosen as the solvent, the color change was not very significant. The contact angle was significantly reduced from 112° before activation to 26° after activation, and the surface energy was greatly enhanced from 34 mN m⁻¹ before activation to 66 mN m⁻¹ after activation. In addition, compared with the FEP samples treated by Ar plasma, the sodium naphthalene system showed a stronger activation ability. Activated FEP films that suffered from the Ar plasma treatment could still maintain a higher energy surface than that of the pristine FEP. Full article

This work examined the influence of cultivar, anti-browning treatment, package atmosphere and storage duration on the oil uptake and polycyclic aromatic hydrocarbons (PAH) levels in fried fresh-cut potato (FCP). Birgit and Lady Claire potato slices were pre-treated with sodium chloride solution (1%) and sodium ascorbate solution (2%), packaged in vacuum and modified atmosphere and stored at 10 °C/8 days. Oil uptake was significantly higher in Birgit FCP and was not affected by minimal processing. HPLC analysis/fluorescence detection was able to identify a total of 14 PAH. Benzo(a)pyrene and ΣPAH4 levels (0.62 and 1.36 µg kg⁻¹, respectively) were below the EU limits in all fried FCP samples. Majority of examined light and heavy PAH were higher in Lady Claire, while naphthalene, fluorene and pyrene were decreased by vacuum packaging. No differences in PAH levels were noted in FCP fried at the beginning and after 2, 4 and 8 days of storage. Full article