Fiber morphology with off-standing branches,as found in nature,e.g.,in goose downy feather,provides exquisite functions that can be barely achieved by man-made fiber systems.In this work,we develop a simple and scalab...Fiber morphology with off-standing branches,as found in nature,e.g.,in goose downy feather,provides exquisite functions that can be barely achieved by man-made fiber systems.In this work,we develop a simple and scalable method for generating downy feather-like para-aramid fibers and assemblies.Through treating commercial para-aramid microfibers with mild alkaline solution(low concentration of NaOH),a synergistic effect of chemical hydrolysis and physical shearing is successfully triggered to generate abundant nanofiber branches on the surface of para-aramid fibers.When compared with conventional monotonous structures,nonwovens composed of downy feather-like fibers exhibit a typical multiscale fiber morphology,larger specific surface area and smaller pore size,thus showing enhanced particles adsorption capacity(over twice of the pristine nonwoven),excellent oil absorption capacity(increased by~50%),improved air filtration performances(doubled the filtration efficiency)and effective thermal insulation(thermal conductivity=26.1 mW·m^(−1)·K^(−1)).More attractively,the intrinsic flame-retardant nature of para-aramid is well inherited by the downy feather-like fibers,and the fabrication process requires neither sophisticated equipment,nor tedious procedures,making us believe the strong competitiveness of these fibers and assemblies.展开更多
为研究对位芳纶沉析纤维这种新型纤维及其复合纸的结构与性能,文中采用光学显微镜、扫描电镜、原子力显微镜表征了纤维的表观形貌;通过纤维质量分析仪分析了纤维的形态参数;利用压汞仪定量表征了复合纸的结构特征,并综合研究了其力学性...为研究对位芳纶沉析纤维这种新型纤维及其复合纸的结构与性能,文中采用光学显微镜、扫描电镜、原子力显微镜表征了纤维的表观形貌;通过纤维质量分析仪分析了纤维的形态参数;利用压汞仪定量表征了复合纸的结构特征,并综合研究了其力学性能、介电性能和热学性能。结果表明,沉析纤维呈薄膜褶皱状,形态柔顺,表面粗糙,在水相介质中分散均匀;重均长度0.552mm,细小纤维含量71.9%,纤维均一性好,细碎化程度高,有利于成纸的增强;芳纶复合纸的孔隙率为18.33%,孔径为14.64μm,成纸结合相对紧密,类似于钢筋混凝土结构;其拉伸指数为38.8 N·m/g,撕裂指数为18.4 m N·m2/g,耐压强度达到21.8 k V/mm;初始分解温度535℃,t10%为560℃,热学稳定性优异。展开更多
基金supported by the Fundamental Research Funds for the Central Universities and Graduate Student Innovation Fund of Donghua University(No.CUSF-DH-D2020021).
文摘Fiber morphology with off-standing branches,as found in nature,e.g.,in goose downy feather,provides exquisite functions that can be barely achieved by man-made fiber systems.In this work,we develop a simple and scalable method for generating downy feather-like para-aramid fibers and assemblies.Through treating commercial para-aramid microfibers with mild alkaline solution(low concentration of NaOH),a synergistic effect of chemical hydrolysis and physical shearing is successfully triggered to generate abundant nanofiber branches on the surface of para-aramid fibers.When compared with conventional monotonous structures,nonwovens composed of downy feather-like fibers exhibit a typical multiscale fiber morphology,larger specific surface area and smaller pore size,thus showing enhanced particles adsorption capacity(over twice of the pristine nonwoven),excellent oil absorption capacity(increased by~50%),improved air filtration performances(doubled the filtration efficiency)and effective thermal insulation(thermal conductivity=26.1 mW·m^(−1)·K^(−1)).More attractively,the intrinsic flame-retardant nature of para-aramid is well inherited by the downy feather-like fibers,and the fabrication process requires neither sophisticated equipment,nor tedious procedures,making us believe the strong competitiveness of these fibers and assemblies.
文摘为研究对位芳纶沉析纤维这种新型纤维及其复合纸的结构与性能,文中采用光学显微镜、扫描电镜、原子力显微镜表征了纤维的表观形貌;通过纤维质量分析仪分析了纤维的形态参数;利用压汞仪定量表征了复合纸的结构特征,并综合研究了其力学性能、介电性能和热学性能。结果表明,沉析纤维呈薄膜褶皱状,形态柔顺,表面粗糙,在水相介质中分散均匀;重均长度0.552mm,细小纤维含量71.9%,纤维均一性好,细碎化程度高,有利于成纸的增强;芳纶复合纸的孔隙率为18.33%,孔径为14.64μm,成纸结合相对紧密,类似于钢筋混凝土结构;其拉伸指数为38.8 N·m/g,撕裂指数为18.4 m N·m2/g,耐压强度达到21.8 k V/mm;初始分解温度535℃,t10%为560℃,热学稳定性优异。
