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聚丙烯腈/碳纳米管复合纳米纤维膜的制备与性能研究
【作者】 孙宁；
【作者基本信息】 青岛大学 ， 材料学， 2008， 硕士
【摘要】 纳米纤维性能优异、广泛应用在防护服,光敏元件,生物医药,航天太阳帆等领域。但是,聚合物纳米纤维的强度由于纤维的直径非常小,因此增强纳米纤维一直是材料领域的一大难点。目前主要采用添加增强材料来增强复合纤维的强度来提高纤维的力学性能。碳纳米管具有非凡的力学性能,高的耐热性和良好的导电性。所有这些性质使其成为了理想的增强聚合物材料。所以本文采用添加碳纳米管来增强腈纶纳米纤维。本文使用浓硝酸和浓硫酸混合溶液将多壁碳纳米管进行功能化处理,而后与聚丙烯腈共混,通过静电纺丝技术成功的制备出了纳米复合纤维薄膜。通过使用IR,TEM和电子能谱仪对氧化处理的多璧碳纳米管(MWNTS)进行了表征,结果表明经过氧化处理后的MWNTs被切短,碳管上引入了羧基和羟基等活性基团,可以长时间的均匀的分散在N,N-二甲基乙酰胺(DMF)中。通过毛细管流变仪和旋转流变仪对PAN/MWNTs溶液的流变性能进行了研究,结果表明PAN/MWNTs溶液是切力变稀的非牛顿流体,即假塑性流体,其流变行为对剪切速率和温度均具有明显的依赖性。通过使用扫描电镜,研究了不同静电纺丝工艺对制备PAN/MWNTs纳米纤维的影响。结果表明当质量分数为10%的纺丝液,并在极距为17.5cm,电压为20kV的工艺条件下,可以制备出直径较细,形态良好的纳米纤维薄膜。通过使用扫描电镜,透射电镜,TG,x衍射和薄膜抗拉强度试验机对纳米纤维薄膜的性能进行了研究,结果表明加入修饰后的MWNTs的PAN复合纤维的形貌较好;MWNTs在PAN纳米纤维中有部分取向,但是取向程度不是很高;添加MWNTs后,纤维薄膜的力学性能得到了提高,但是对热性能并没有太大的影响。
【Abstract】 Electrospun nanofibers with excellent properties were found to be used in protective clothing, optical sensors, and for solar sails in space. However, the polymer nanofibers fabricated by electrospinning processes were not strong enough for their very small diameter. So making nanocomposites was a more promising way to reinforce the nanofibers. Also, carbon nanotubes (CNTs) had attracted great interests due to their unique mechanical, electrical, magnetic, optical and thermal properties. All of these properties made carbon nanotubes an ideal material for reinforcing polymer materials. So making PAN/MWNTs nanofibers was a better way to reinforce the PAN nanofibers.Continuous composite nanofiber sheets made from polyacrylonitrile (PAN) and surface-oxidized Multiwall Carbon Nanotubes (MWNTs) were successfully fabricated by electrospinning.The acid-treated MWNTs were examined by FITR, TEM, SEM. The results showed that after MWNTs were modified, carboxylic acid groups were found in the surface of MWNTs and MWNTs were well dispersed in DMF.The rheological properties were studied by rheometer. The result exhibited that the rheological properties of the DMF solution of PAN/MWCNTs belonged to pseudoplastic fluid, and shows shear thinning. The rheological properties had greatly related with temperature and shear rate.Scanning electron microscope (SEM) photos showed the change of the morphology of the electrospun PAN/MWNTs fibers according to the differentprocessing parameters. The results showed that when the solution concentration of was 10%,spinning voltage was 20 kV, the distance of collection was 17.5cm, the good morphology of PAN/MWCNTs composite nanofibers electrospun.The properties of nanofiber sheets were studied by SEM, TEM, X-ray, TG and the membrane tensile testing. The results showed that the acid treated MWNTs/PAN nanofiber was smooth and thin. TEM showed that the part of carbon nanotubes were aligned in nanofibers via electrospinning. The X-ray showed that most of MWNTs were not aligned in nanofiber. .The adding of MWNTs greatly improved the mechanical properties of nanofiber sheets, but had no contribution to thermal properties.