【作者】 廖若谷；

【导师】 史铁钧；

【作者基本信息】 合肥工业大学 ， 材料学， 2005， 硕士

【摘要】 电纺是一种制备纳米纤维的新方法,它利用高压静电驱使聚合物溶液(或熔体)喷射而形成纳米级纤维(直径可小于100nm而长度可达数千米)。传统的纺丝技术(干纺、湿纺、熔体纺丝、胶体纺丝等)生产的纤维直径在几到几百微米的范围内,而电纺技术生产的纤维直径可小于100nm。由于形成的纤维的直径较小,具有较大的比表面积,因此它在过滤和膜材料方面有广阔的应用前景,同时它在生物医学材料,增强复合材料方面也有很大的前景。 本文的工作主要集中在以下几个方面: 第一,为了对电纺过程有一个全面的了解,将聚氧化乙烯(PEO)水溶液在不同的工艺条件下进行电纺,制备了PEO纤维。用扫描电镜(SEM)研究了纤维的直径及分散形态;用DSC和XRD研究了纤维的结晶性能。电纺纤维分散形态是由浓度、电压、固化距离等因素综合作用的结果。其中,浓度是最关键的因素,降低溶液浓度、提高静电压、增加固化距离均会使纤维变细。电纺得到的纤维与PEO原粉相比,结晶度下降,从理论上分析了可能的机理。 第二,用电纺技术制备了酚醛纤维及碳纤维。用合成的甲阶酚醛(A-stageresol)和聚乙烯醇(PVA)在不同配比下进行电纺,将得到的纤维在150℃固化处理1h,制得酚醛(PF)纤维。将PF和PVA质量比为1:2的酚醛纤维在不同的温度下进行热处理,得到的纤维直径均小于200nm。用场发射扫描电镜(FESEM)观察并比较了纤维的直径和分散形态。用红外光谱(IR)证实了在600℃下热处理后的酚醛纤维为碳纤维,分散形态最为理想。 第三,用电纺方法制备了聚丙稀腈(PAN)纳米纤维,用FESEM对其形态进行了研究,讨论了不同工艺参数对纤维直径和分散形态的影响。结果发现纤维直径随着浓度的增加而增大,电压升高而减小,接收距离和溶剂类型对纤维直径的影响不大。将形态最好的纤维在240℃下进行活化处理,然后将活化处理过的纤维在氮气氛中煅烧,用FESEM观察了煅烧的纤维直径及形态的变化,红外(IR)分析了纤维化学结构的变化,证实了经900℃煅烧后的纤维为碳纤维。更多还原

【Abstract】 Electrospinning is a novel method to produce nanofibers. It is a process by which polymer fibers (with diameter lower than 100nm and lengths up to kilometers) can be produced using static electricity of high-voltage which compel polymer solution (or polymer melt) to jet.The diameter of fibers produced by conventional spinning technology (wet spinning,dry spinning, melt spinning, gel spinning etc.) is from several to several hundred microns, however, the diameter of efectrospinning fibers can be less than 100 nm. Because of its small diameter, the fiber has large specific surface area. It can be used as filtration and film materials. Furthermore it has many potential applications in biomaterials and composite materials.The work in this paper included:First, in order to learn electrospinning process comprehensively, poly(ethylene oxide)(PEO)/water solutions were electrospun under different technological parameters to prepare nanofiber. Dispersion morphology of electrospun fibers was characterized by scanning electron microscopy(SEM). Crystallization property of electrospun fibers was characterized by differential scanning calorimetry(DSC) and X-ray diffraction(XRD). Dispersing morphology of electrospun fibers was affected by the solution concentration, the voltage and the distance between two electrodes. In all parameters, the concentration and voltage were the key factors. When the concentration was reduced, the voltage was increased and the distance between two electrodes was boosted, electrospinning fibers gradually became fine. Compared with PEO powder, electrospinning fibers crystallinity declined, and the possible mechanism was analysed theoretically.Second, synthetical A-stage resol and PVA solution at different mass ratio were electrospun into fibers. After solidified at 150℃ for an hour, phenol formaldehyde (PF) fibers were obtained. When the PF fibers(mass ratio of PF and PVA were 1:2) were calcined at different temperature, the fibers sized less than 200 nm in diameters based on PF were obtained. By field emission scanning electron microscopy(FESEM), the diameter and morphology of the fibers were observed and compared. The infrared(IR) spectra showed that the fibers calcined at 600℃ werecarbon fibers and it was found that morphology of the fibers were the best.Third, the fiber of polyacrylonitrile(PAN) were fabricated by means of electrospinning.With the help of FESEM, the morphology of PAN fiber were investigated. The influence of electrospinning parameters on diameter and morphology of fiber ware discussed. It was found that the diameter of the fiber increased with the increasing of solution concentration and decreasing of electrospinning voltage, and other factors have few influences on fiber diameter. The best fibers were calcined at 240 °C in air and then calcined in nitrogen at higher temperatures. The transformation of fiber diameter and morphology was observed by means of FESEM. The chemical structure of the fibers was analyzed by IR, and it was conformed that the fiber calcined at 900 °C were carbon fiber.更多还原