ABSTRACT:The influence of compatibilization on the dynamic mechanical properties of polypropylene (PP) binary blends with polyamide-6 (PA6), Talc, and oxidized PP (OPP) was investigated. The oxidation of PP homopolymer was performed in a internal mixer by using air as a oxidizing agent (under atmospheric pressure) and dodecanol-1 as an accelerator at 180°C for 6[1-2] h [Abdouss, M.; Sharifi-Sanjani, N.; Bataille, P. J Appl Polym Sci 1999, 36, 10]. In the blends, OPP was used as a blend component and compared with PP over the whole concentration range. Pressed film blends of PP/OPP, PP/OPP/Talc, and PP/OPP/PA6 were examined by dynamic mechanical analyzer, thermal gravimetry analysis, and scanning electron microscopy. Mechanical properties such as tensile strength, modulus of elasticity, elongation, melt flow index, and hardness of the blends were measured.
Based on the solidification of a hydrophobic deep eutectic solvent in air‐assisted liquid phase microextraction combined with gas chromatography and mass spectrometry, a green and sustainable microextraction technique was developed for extracting, separating, and detecting organophosphorus flame retardants in aqueous samples. In this study, some strategies were considered for overcoming or improving the challenges of conventional solvent microextraction procedures. In addition, a hydrophobic deep eutectic solvent with a freezing point near the ambient temperature was employed as an extraction phase, the dispersive solvent was substituted by the syringe pump process, and the centrifugation step was omitted by using salting‐out phenomenon. Further, the effect of the main independent variables was evaluated by using the chemometric methods in order to maximize the extraction efficiency of the procedure. Under optimal conditions, the calibration model was linear in the range of 0.01–25.0 µg/L. Limits of detection and quantitation were assessed at the concentration levels of 2–23 and 9–65 ng/L, respectively. The precision involving repeatability and reproducibility was evaluated by estimating the relative standard deviation, the levels of which were <6.6 and <8.7%, respectively. The applicability of the method was successfully evaluated by analyzing the target analytes in real aqueous samples, which illustrated satisfactory recoveries (95–104.61%).
Background:The essential oil of Lavandula angustifolia Mill. (L. angustifolia), a species from the Lamiaceae family, possesses several biological activities; therefore it is used in some herbal medicines. The lack of studies into identifying the essential oil of L. angustifolia and its similar appearance to Nepeta menthoides Boiss. & Buhse (N. menthoides) as "Ustukhuddoos" in Iranian traditional medicine, have caused misuse and adulteration in the products. Objective: In this study, the chemical compositions of L. angustifolia and N. menthoides essential oils, and three commercial herbal medicines of L. angustifolia essential oil in Iranian markets were evaluated and investigated as adulteration with the help of GC/MS analysis and chemometric methods. Methods: The essential oils of L. angustifolia and N. menthoides, and commercial samples were extracted by different extraction methods. Furthermore, their chemical compositions were evaluated by GC/MS analysis. After identification of components by GC/MS, the obtained results were assessed by principal component analysis (PCA, Unscrambler X version 10.4) for clustering. Results: Results showed that all three commercial herbal preparations matched with the manufacturer's claim about using L. angustifolia essential oil in the products. PCA distinguished two groups which were characterized based on different types and amounts of the components. Conclusion: GC/MS analysis with the help of chemometric methods is a powerful method to evaluate and discriminate between the essential oils and their products. In general, the combination of instrumental analysis and clustering chemometric analysis can provide an accurate tool for identifying misuse between plant species.
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