Nitrogen-doped carbon/graphene (NCG) hybrid materials were prepared by an in-situ polymerization and followed pyrolysis for sodium-ion batteries. The NCG has a large interlayer distance (0.360 nm) and a high nitrogen content of 7.54 at%, resulting in a high reversible sodium storage capacity of 336 mAh g -1 at 30 mA g -1 .The NCG shows a sandwich-like structure, i.e. nitrogen-doped carbon nanosheets closely coated on both sides of graphene. The carbon nanosheets shorten the ion

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A vinyl isocyanate (VI) synthesized from toluene diisocyanate and 2-hydroxyethyl methacrylate was used as a novel coupling agent to obtain strong chemical interfacial adhesion and therefore, improve the tensile properties of Kraft fiber-reinforced unsaturated polyester (UPE) composites. Results characterized by fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), and scanning electron microscope (SEM) indicated that the novel coupling agent VI had a significant effect on the tensile properties of composites due to the formation of chemical bonds between the VI-Kraft interfaces and the VI-UPE interfaces. The tensile properties of composites modified by VI were much better than those of the control composite without VI modification. The VI-modified composites after severe hygrothermal aging exhibited lower losses of tensile properties and desirable tensile durability. The improvement in tensile properties, less interfacial separation after severe hygrothermal aging, lower damping values, and higher glass transition temperature are sufficient to show that the interfacial adhesion between the Kraft fiber and the UPE matrix was significantly improved because the coupling agent VI has both active isocyano groups which react with the Kraft fiber and vinyl groups which are copolymerizable with the UPE resin.