WPU/Starch复合增强碳纳米纤维气凝胶的制备及性能研究

Preparation and properties of WPU/Starch composite reinforced carbon nanofiber aerogel

通过调整常规碳气凝胶的制备工艺,将聚丙烯腈(PAN)预氧化纤维炭化步骤提前,制备PAN基碳纳米纤维(CNF);以CNF作为气凝胶骨架、可溶性淀粉(Starch)及水性聚氨酯(WPU)作为纤维黏合剂,通过冷冻干燥、热处理的方式制备WPU/Starch复合增强CNF气凝胶;研究了Starch及WPU的添加质量比对CNF气凝胶的微观形貌、疏水性能、力学性能的影响。结果表明:WPU与Starch在气凝胶热处理过程中发生了热交联,CNF气凝胶的纤维之间形成的薄膜为蛛网状多孔结构,内部呈现层状结构,有利于提高CNF气凝胶的疏水性和回弹性;随着WPU添加量的增加,CNF气凝胶的疏水性逐渐提高,当WPU与Starch的质量比为2.01.0时,CNF气凝胶的水接触角为150.8°,达到超疏水的疏水性能,且对常用的有机试剂表现出良好的吸附能力;当WPU与Starch的质量比为1.51.0时,CNF气凝胶在60%形变下压缩循环500次后塑性形变仅9.6%,所承受的压缩应力保持初始状态的85.4%,具有良好的回弹性。

By adjusting the preparation process of conventional carbon aerogels,PAN based carbon nanofibers(CNF)were prepared through the advance of carbonization of polyacrylonitrile(PAN)pre-oxidized fibers.Using CNF as aerogel skeleton and soluble starch(Starch)and waterborne polyurethane(WPU)as fibrous adhesive,WPU/Starch composite reinforced CNF aerogels were prepared by freeze-drying and heat treatment.The influence of the mass ratio of Starch and WPU on the micromorphology,hydrophobicity and mechanical properties of CNF aerogels was studied.The results showed that WPU and Starch were thermally cross-linked during the aerogel heat treatment process,and thus the films between the fibers of CNF aerogel formed with spider net porous structure and a layered structure inside,which was beneficial to improving the hydrophobicity and resilience of aerogels;the hydrophobicity of CNF aerogels gradually increased with the increase of WPU addition,and CNF aerogels exhibited the superhydrophobic properties with the water contact angle of 150.8°and good adsorption capacity for normal organic reagents when the mass ratio of WPU to Starch was 2.01.0;and CNF aerogels had only 9.6%plastic deformation,compressive stress remaining 85.4%of the initial value and good resilience after 500 cycles of compression under 60%deformation when the mass ratio of WPU to Starch was 1.51.0.