Abstract. The procedures for the synthesis of polypyrrole (PPy) doped with anionic spherical polyelectrolyte brushes (ASPB) (PPy/ASPB nanocomposite) by means of in situ chemical oxidative polymerization were presented. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopic analysis suggested the bonding structure of PPy/ASPB nanocomposite. Scanning electron microscopy (SEM) was used to confirm the morphologies of samples. The crystallographic structure, chemical nature and thermal stability of conducting polymers were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Thermo-gravimetric analysis (TGA) respectively. Investigation of the electrical conductivity at room temperature showed that the electrical conductivity of PPy/ASPB nanocomposite was 20 S/cm, which was higher than that of PPy (3.6 S/cm).

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The advancement in science and technology has led to luffa sponge (LS) being widely used as a natural material in industrial application because of its polyporous structure and light texture. To enhance the utility of LS fibers as the reinforcement of lightweight composite materials, the current study investigates their water absorption, mechanical properties, anatomical characteristics and thermal performance. Hence, moisture regain and tensile properties of LS fiber bundles were measured in accordance with American Society for Testing and Materials (ASTM) standards while their structural characteristics were investigated via microscopic observation. Scanning electron microscopy (SEM) was used to observe the surface morphology and fractured surface of fiber bundles. The test results show that the special structure where the phloem tissues degenerate to cavities had a significant influence on the mechanical properties of LS fiber bundles. Additionally, the transverse sectional area occupied by fibers in a fiber bundle (SF), wall thickness, ratio of wall to lumen of fiber cell, and crystallinity of cellulose had substantial impact on the mechanical properties of LS fiber bundles. Furthermore, the density of fiber bundles of LS ranged within 385.46–468.70 kg/m3, significantly less than that of jute (1360.40 kg/m3) and Arenga engleri (950.20 kg/m3). However, LS fiber bundles demonstrated superior specific modulus than Arenga engleri.

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Single crystalline palladium arrow-headed tripods prepared via a simple one-pot strategy exhibit high electro-activity in formic acid oxidation, which could be a promising anodic catalyst for direct formic acid fuel cells.