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A novel boron‐containing novolac (triphenyl borate‐formaldehyde resin, TPBF) was synthesized. The structure, thermoplasticity, molecular weight, and molecular weight distribution of TPBF have been characterized with FT‐IR, melt viscosity, 13C NMR and GPC. The thermal stability of TPBF was investigated by TGA, indicating the thermal stability of TPBF was much better than that of normal novolac (phenol‐formaldehyde resin, PF). TPBFs with different molar ratios of formaldehyde to benzene ring in triphenyl borate (TPB) were also synthesized and compared for molecular size, polydispersity and thermal stability. Further, the thermal degradation kinetics of TPBFs and PF were studied by TGA using Madhusdanan‐Krishnan‐Ninan method and the activation energies were calculated at different degradation stages. It was found that the thermal degradations of TPBFs and PF are a multistage reaction and the degradation reactions in every stage follow the first order reaction mechanism. Finally, the activation energies of thermal degradations of novolac increase with the introduction of boron, the progress of degradation reaction as well as the increase of molar ratios. [ABSTRACT FROM AUTHOR]

Flexible electronic devices and conductive materials can be used as wearable sensors to detect human motions. However, the existing hydrogels generally have problems of weak tensile capacity, insufficient durability, and being easy to freeze at low temperatures, which greatly affect their application in the field of wearable devices. In this paper, glycerol was partially replaced by water as the solvent, agar was thermally dissolved to initiate acrylamide polymerization, and MXene was used as a conductive filler and initiator promoter to form the double network MXene-PAM/Agar organic hydrogel. The presence of MXene makes the hydrogel produce more conductive paths and enforces the hydrogel's higher conductivity (1.02 S·m−1). The mechanical properties of hydrogels were enhanced by the double network structure, and the hydrogel had high stretchability (1300%). In addition, the hydrogel-based wearable strain sensor exhibited good sensitivity over a wide strain range (GF = 2.99, 0–200% strain). The strain sensor based on MXene-PAM/Agar hydrogel was capable of real-time monitoring of human movement signals such as fingers, wrists, arms, etc. and could maintain good working conditions even in cold environments (−26 °C). Hence, we are of the opinion that delving into this hydrogel holds the potential to broaden the scope of utilizing conductive hydrogels as flexible and wearable strain sensors, especially in chilly environments. [ABSTRACT FROM AUTHOR]

Abstract: Hollow nanospheres of Sn–Sb–Cu alloy composites have been successfully synthesized via co-reduction of metal chlorides in aqueous alkaline solution without using any surfactants or solid templates. A bubble assisted growth mechanism is proposed to account for the formation of the hollow nanostructures. The concentration of the reactants kinetically controls the nucleation rate of the alloy nuclei, making for the formation of the hollow nanospheres. Compared with the alloy nanoparticles, the hollow spheres exhibit relatively high electrochemical capacity and good cyclic retention when used as anode materials for lithium-ion batteries. The bubble assisted synthesis method can be readily explored for fabricating hollow nanostructure of other alloy system for functional material applications. [Copyright &y& Elsevier]