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In this study, modified TiO 2 grafted flax fibers were used to reinforce PLA composites. The fibers were oxidized in order to improve the interfacial adhesion of the fibers to TiO 2 film. The TiO 2 film was created on the flax fiber by a Sol-Gel dip-coating technique. The interfacial adhesion of the fibers to the matrix was investigated qualitatively by microscopy, and quantitatively by measuring inter-laminar shear strength. Impact and tensile tests characterized the mechanical properties of the modified TiO 2 grafted flax fiber reinforced composites. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Dynamic mechanical analysis (DMA) were used to reveal the thermal and thermo-mechanical behavior of the composites. The hygroscopic behaviors of the composites were determined by the water uptake assessment. The results showed statistically significant increase in adhesion bonding of the modified fibers to the matrix. The modified TiO 2 grafted flax fibers increased the impact resistance of pure PLA by three times. The microscopic observations verified the modifications in the mechanical and physical properties of the composites. Moreover, the amount of water sorption decreased by 18% in the modified TiO 2 grafted fiber reinforced composite. [ABSTRACT FROM AUTHOR]

Condition monitoring of power electronics is gaining interest as power electronics expends to mission-critical applications. This paper offers a preliminary experimental study of the viability of using S-parameters and time-domain reflectometry measurements to monitor the degradation of a power module. To this end, measurements were performed on a standard high current power module which was artificially aged by cutting wire bonds one by one. The study demonstrates a clear trend in the evolution of measured parameters, and thereby the possibility to monitor the power module degradation under the specific test conditions. This opens a new condition monitoring technology for power electronics systems. • RF technologies are used for State of Health assessment. • Power electronics ageing is detected using S-parameters and TDR. • S-parameters are used for condition monitoring of power electronics. [ABSTRACT FROM AUTHOR]

This study aims at functionalizing flax fibers by grafting an amphiphilic TiO2 thin film. The film was created on the fiber by the Sol-Gel technique. The fibers were firstly primed to reach a minimum possible roughness, and then were coated using the dip-coat method. The crystalline structure and the morphology of the TiO2 particles, and, the TiO2-grafted film were determined using X-ray diffraction, and Transmission Electron Microscopy. Mechanical properties of the TiO2-grafted flax strands were investigated by a tensile test. Dynamic contact angle tensiometer was used to probe the differences between wettability of the TiO2-grafted and non-grafted flax strands. The results show that the particles obtained from the Sol-Gel technique created a 100 nm-thick film of TiO2 in the anatase form. The statistical evaluation of the tensile tests exhibits a significant improvement in mechanical properties of the TiO2-grafted flax strands. Moreover, the TiO2 coated flax fibers show a wide range of wetting angles in comparison with the other samples. [ABSTRACT FROM AUTHOR]

Abstract: A synthetic saponite-like clay, Sumecton SA (SSA), was self-assembled with 12-phosphotungstic acid (PTA) heteropolyacid for the preparation of new hybrid nanocomposites for proton exchange membranes. Thermogravimetric analysis (TGA) and Fourier transformed diffuse reflectance spectroscopy (DRIFT) measurements indicate the formation of robust PTA–SSA complexes. The Keggin structure of PTA is preserved within the complexes and is thermally stable up to 450°C. The amount of PTA incorporated into the clay depends on the PTA–SSA weight ratio used for the complex preparation. PTA incorporation achieved is approximately 2–3 times the PTA content of most reported literature. However, higher PTA incorporation is accompanied by a significant loss of structural clay integrity. Low PTA–SSA weight ratios tend to preserve clay structure, but do not preclude its general amorphization generated by the PTA acidic treatment. PTA–SSA complexes present a low degree of order. Inorganic complexes were blended by melt extrusion with chemically-modified styrene/ethylene-co-butylene/styrene block copolymer (SEBS). Poly(oxyethylene/oxypropylene)-grafted-SEBS is more efficient than maleic anhydride-grafted-SEBS at dispersing PTA–SSA complexes. For both nanocomposite systems, nanoparticles’ size varies between 30 and 300nm. [Copyright &y& Elsevier]