Lightweight conductive graphene/thermoplastic polyurethane foams exhibited stable piezoresistive sensing signals at a strain of up to 90%.

This review paper summarizes the categories, sensing mechanisms, and affecting factors of flexible conductive polymer composite-based stretchable strain sensors.

Graphene presents an extremely ultra-high thermal conductivity, well above other known thermally conductive fillers. However, graphene tends to aggregate easily due to its strong intermolecular π−π interaction, resulting in poor dispersion in the polymer matrix. In this study, silver nanoparticles anchored reduced graphene oxide (Ag/rGO) were first prepared using one-pot synchronous reduction of Ag + and GO solution via glucose. The thermally conductive (Ag/rGO)/polyimide ((Ag/rGO)/PI) nanocomposites were then obtained via electrospinning the in situ polymerized (Ag/rGO)/polyamide electrospun suspension followed by a hot-press technique. The thermal conductivity (λ), glass transition temperature (T g ), and heat resistance index (T HRI ) of the (Ag/rGO)/PI nanocomposites all increased with increasing the loading of Ag/rGO fillers. When the mass fraction of Ag/rGO (the weight ratio of rGO to Ag was 4:1) fillers was 15%, the corresponding (Ag/rGO)/PI nanocomposites showed a maximum λ of 2.12 W/(m K). The corresponding T g and T HRI values were also enhanced to 216.1 and 298.6 °C, respectively. Furthermore, thermal conductivities calculated by our established improved thermal conduction model were relatively closer to the experimental results than the results obtained from other classical models.

Lead-free piezoelectric materials and innovative piezoelectric devices provide a solution to the energy and environmental crisis we are now faced with.

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A NiSe–G∥AC asymmetric supercapacitor with both pseudocapacitance and EDLC mechanisms provides an energy density of 50.1 W h kg−1 and a power density of 816 W kg−1.

The influence of two kinds of polymers (polystyrene (PS), acrylonitrile−styrene copolymer (SAN)) on the crystallization behavior of isotactic polypropylene (iPP) has been investigated by means of wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and polarized optical microscopy (POM). The current experimental results indicated that these two kinds of polymers with low concentration, as special β-nucleating agents, can induce the β-iPP polymorph during quiescent melt crystallization. The nucleating activity of SAN or PS significantly depends on its concentration, molecular structure, and thermal history of processing. The content of β-crystal form increases with the increasing crystallization temperature or nucleating agent (SAN or PS) percentage, reaches a maximum value, and then decreases as the temperature or nucleating agent percentage further increases. Under the same crystallization condition, SAN is more effective than PS on inducing a higher level of β-crystal form in iPP. Besides, variable temperature WAXD and POM experiments have been used to investigate the polymorphism and the crystalline phase transformation of iPP. It was proved that the β-crystal form of iPP is a thermodynamically metastable structure and will gradually transform to a new kind of α‘-crystal form with the rise in crystallization temperature. Because of different structural characteristics, the polymeric nucleating agents exhibit nucleation and crystallization mechanism which differ from the traditional low molecular weight β-nucleating agents of iPP.

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