| Kevlar nanofibers?ANFs?have excellent strength and modulus,which are promising new polymer reinforcing fillers.However,the surface polarity of ANFs is low and its dispersion in water is poor,which limit its application.Therefore,it is necessary to modify the surface of ANFs to improve the dispersion of ANFs in water and expand its application in polymers.In this paper,Kevlar nanofibers with good water dispersibility?hANFs?were prepared by hydrothermal acidolysis of ANFs.The hANFs had a large number of polar terminal groups on the molecular chains as well as retained the crystal structure and one-dimensional fiber morphology of ANFs.However,its thermal stability was slightly decreased.Carboxylated acrylonitrile butadiene rubber?XNBR?/hANFs composites were prepared by an emulsion blending method.The interaction between hANFs and XNBR and the effects of the amount of hANFs on the performance of XNBR were investigated.The results showed that there was hydrogen bonding between hANFs and XNBR,and the hydrogen bonding gradually increased with the increase of hANFs content.Compared with unfilled XNBR,the tensile strength and tear strength of XNBR/hANFs composites with 7 phr of hANFs were increased by236%and 161%,respectively.The glass transition temperature?Tg?and maximum thermal decomposition temperature(Tmax)were increased by 2.68°C and 19.64°C,respectively.The solvent resistance and dielectric properties were also improved.Styrene butadiene rubber?SBR?/hANFs composites were fabricated by mixing hANFs aqueous dispersion with SBR latex.The interaction between hANFs and SBR and the effects of the amount of hANFs on the properties of SBR were studied.The results showed that hANFs dispersed uniformly in SBR,and mainly combined with SBR through?-?interaction.With the increase of hANFs content,the interaction between hANFs and SBR increased gradually.Compared with neat SBR,the tensile strength and tear strength of SBR/hANFs composites with7 phr of hANFs were increased by 215%and 148%,respectively.Thermal stability and solvent resistance of SBR/hANFs composites were also improved to some extent.Natural rubber?NR?/hANFs composite membranes were prepared by simple evaporation method.The effects of the amount of hANFs on the properties of the composite membranes were investigated.The results indicated that the Tmax and tensile strength of the NR/hANFs composite film filled with 20 phr of hANFs were increased by 2.64°C and 347%,respectively,compared with the unfilled NR film.NR/hANFs composite membranes had a certain water-stimuli mechano-responsive property.After water absorption,the storage modulus?E??at room temperature?25°C?of N-hANFs20 could be reduced by 57.2%. |
PDF Full Text Request