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A polypyrrole‐coated rubber foam sorbent with a steel wire insert was developed for the magnetic solid phase extraction of fipronil and fipronil sulfone from tea samples for analysis by a gas chromatography‐electron capture detector. Under the optimum conditions, the method linear ranges were 0.05–100 μg/L for fipronil and 0.01–100 μg/L for fipronil sulfone. The limits of detection were 0.01 and 0.005 μg/L while limits of quantitation were 0.05 and 0.01 μg/L for fipronil and fipronil sulfone, respectively. The preparation procedure of the developed sorbent exhibited good reproducibility with a relative standard deviation in the range of 1.9%–2.4% spiked at 50 μg/L. Good precision was obtained with a relative standard deviation below 6.7% in four concentrations ranging from 0.0 to 50 μg/L. Fipronil sulfone was detected in two tea samples at concentrations of 1.79 ± 0.05 and 2.64 ± 0.03 μg/L with recoveries ranging from 80.4 ± 1.5% to 110.0 ± 2.0%. Thus, the developed sorbent exhibited high extraction efficiency with good selectivity towards the target analytes in real samples. [ABSTRACT FROM AUTHOR]

This work aims to compare the performance between natural rubber (NR) composites with lead oxide (PbO) and bismuth oxide (Bi2O3) as shielding fillers for gamma radiation shielding applications. Modulus at 100% elongation, tensile strength, elongation at break, hardness and a specific gravity of the NR composites were investigated. The results indicated that NR/Bi2O3 and NR/PbO composites have no significant difference in terms of modulus and hardness values, while the NR/PbO composite exhibited better tensile strength and specific gravity than that of NR/Bi2O3 composite. However, NR/Bi2O3 composite exhibited better performance in oil resistance and thermal stability than the one with PbO. Gamma radiation shielding properties including mass attenuation coefficient ( μ m ), effective atomic number (Zeff), effective electron density (Ne) and half-value layer (HVL) have also been studied. It is seen that both the composites exhibited better radiation shielding properties. Furthermore, the radiation properties were in good agreement with the calculated theoretical values. In addition, both the composites of NR with PbO and Bi2O3 particles showed excellent radiation shielding properties compared to neat NR as well as commercially available materials including window, ordinary concrete and haematite-serpentine. The material developed in the present investigation can be used as efficient flexible radiation shielding materials. However, lead (Pb) is not suitable to use as a radiation shielding material due to its toxic nature to the human and the environment. Therefore, NR with Bi2O3 is an appropriate choice for producing novel wearable radiation shielding materials to manufacture gloves, aprons, rubber underwear and other wearable materials. [ABSTRACT FROM AUTHOR]

The objective of this work is to study the feasibility of reinforcing polymer composites by utilizing the biofibers from the agricultural residue of Moringa oleifera pod husks (MOPH). The chemical and physical properties of the fibers were comprehensively investigated to evaluate their potential as a filler in gelatin-based films. The effect of MOPH fiber concentrations of 0, 5, 10, and 15 wt% on the water vapor permeability (WVP), and mechanical and thermal properties of the gelatin-based films was studied. By incorporation of 10 wt% of the MOPH fibers in gelatin, the highest tensile strength and Young’s modulus, and the lowest WVP properties were obtained. Scanning electron microscopy (SEM) photographs indicated good interfacial adhesion between the fibers and the gelatin matrix. TGA of the biocomposites revealed an improvement of thermal stability. Moreover, under accelerated weathering, the gelatin-MOPH-10% biocomposite degraded more slowly than the gelatin control. These results indicate that the MOPH fibers are a good reinforcing filler and may be useful for biocomposite applications. [ABSTRACT FROM AUTHOR]