Development of magnetoresistive thin film sensor for magnetic field sensing applications AIP Conf. Proc. 1512, 30 (2013); 10.1063/1.4790897 FeNi-based magnetic layered nanostructures: Magnetic properties and giant magnetoimpedance FIG. 2. TEM image (a) and PSD (b) of iron oxide MNPs. 193702-2Kurlyandskaya et al.

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The incorporation of viscoelastic materials represents an effective strategy to reduce the vibratory level of structural components. Thermoplastic vulcanizates (TPVs) are a special type of viscoelastic material that combines the elastomeric properties of rubbers with the easy processing of thermoplastics. In the present work, we propose innovative ways to improve the damping properties of high-performance TPVs by using rubbers with carboxylic functionalities. For that, TPVs from physical blends of carboxylated hydrogenated acrylonitrile butadiene rubber (XHNBR) and polyamide 6 (PA6) were prepared. The chain dynamics of different mixed crosslink systems containing peroxide, metal oxides and hindered phenolic antioxidants were investigated in order to find the most suitable strategy to design a high-performance TPV system with upgraded damping properties. The results indicate that the damping performance of the TPV system can be tailored by controlling the type and magnitude of the bonding interactions between the mixed crosslink system and the XHNBR rubber phase. Therefore, this study demonstrates the potential of TPV systems containing carboxylic rubbers as high-performance damping materials.

Carbon fiber sheet molding compounds (C-SMCs) are discontinuous fiber reinforced composite materials. Among them, epoxy-based C-SMCs are becoming relevant materials due to their high thermomechanical performance and better formability than continuous fiber reinforced composites. The thermomechanical performance of epoxy resins and epoxy based continuous carbon fiber composites have shown to be influenced by hygrothermal aging. In this work, this influence is studied for an epoxy-based C-SMC. Epoxy-based C-SMC samples were hygrothermally aged by means of accelerated conditioning, exposing them to 65% relative humidity, and 80 C in a climatic chamber. The equilibrium moisture content, as well as the moisture diffusion coefficient has been determined. The thermomechanical properties of epoxy C-SMC have been analyzed by dynamic mechanical analysis, tensile, 3-point bending, and short beam tests in dry and aged samples. The results showed that epoxy C-SMC is affected by hygrothermal aging in the cases of moisture intake and its effects on T g value, but interestingly, the hygrothermal aging did not generate any degradation effects in the mechanical response of epoxy C-SMC.

With the aim of curbing air pollution and addressing climate change, the use of low density thermoplastic elastomers (TPEs) in transportation could be a useful way to lighten the vehicle weight. For that, melt blending of high performance rubber and thermoplastics is an attractive way of preparing high performance TPEs. In this work, several TPEs have been prepared by melt blending of hydrogenated acrylonitrile butadiene rubber (HNBR) with polyamide 6 (PA6), adding different amounts of carboxylated HNBR (XHNBR) as compatibilizer: 40/60/0, 40/42/18, 40/30/30 and 40/18/42 (PA6/HNBR/XHNBR). The resulting blends were investigated using melt rheological measurements, morphological observations (scanning electron microscopy and polarized optical microscopy), dynamic mechanical analysis, differential scanning calorimetry analysis and mechanical tests. A biphasic morphology was noted for all TPEs. An increase in XHNBR amount changes the morphology from dispersed to co-continuous. This evolution is explained by the change in the melt rheological properties of the HNBR/XHNBR rubber phase. Moreover, the introduction of 42% XHNBR resulted in an increase in the glass transition temperature of both rubber and PA6 phases. This double T g increase phenomenon was attributed to the interfacial interactions between the carboxyl groups in XHNBR and the amine end groups in PA6. Additionally, thermal analysis revealed a reduced crystallinity of PA6 in the blend, which corresponds to enhanced interfacial interactions. The interfacial adhesion and the co-continuous morphology resulted in an improved ductility. This study reveals the possibility of obtaining TPE blends with tunable thermal and mechanical properties by controlling both interfacial interactions and morphology.

Sheet molding compounds (SMCs) have considerable potential as lightweight alternative to traditional materials used in automotive components. However, despite their outstanding mechanical properties, their vibration damping characteristics are often relatively poor for several applications. Therefore, enhancing the vibration damping capability of SMCs represents a field with increasing interest. Application of viscoelastic layers to high stiffness materials, such as SMCs, represents an effective approach to add vibration damping functionalities to lightweight structural components. In this work, the incorporation of thermoplastic elastomers (TPEs) is studied as a novel strategy to enhance the structural vibration damping capability of SMCs. Several types of SMC and TPEs have been considered and the effect of TPE‐SMC thickness ratio on the damping and stiffness properties is investigated. The viscoelastic properties and vibration damping performance were evaluated by dynamic mechanical analysis. The effect of TPE addition on stiffness was studied by three‐point bending. Results reveal the potential of the incorporation of thin TPE layers as cost‐effective strategy to enlarge the vibration damping efficiency of SMCs while maintaining their overall high stiffness. It is expected that the bi‐material configurations presented in the current study will contribute to advance the development of new lightweight multi‐functional solutions for modern transport applications.

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