【作者】 张朝群；

【导师】 李耀先； 杨清彪；

【作者基本信息】 吉林大学 ， 有机化学， 2011， 博士

【摘要】 随着纳米科技的发展和进步,许多性能及应用优异的的纳米材料已经被制备出来,并成为了当今社会中不可缺少的材料。在纳米材料的制备方法中,静电纺丝法作为一种简单易控、高效低耗的新兴技术倍受科学家的青睐。然而,随着人类生产生活的发展,单一结构纳米材料已经远远不能满足需要。无机／有机复合纳米材料由于其在电子学、医学、催化、环保等领域的广泛应用,成为了纳米材料领域的热点。然而对于上述应用而言,无机粒子的粒径分布及材料的机械性能对其应用起到至关重要的影响。在本论文的第二章中,我们采用高压静电纺丝法制备了不同形貌的PAN纳米纤维材料,观察了纺丝原液浓度升高过程中,纳米材料从纳米球到纳米纤维的过渡过程。在静电纺丝得到形貌均一,直径分布均匀的PAN纳米纤维的基础上对PAN纳米纤维膜进行化学改性,引入具有螯合金属离子能力的偕胺肟基团,最后制得了Ag/PAN, Pd/PAN复合纳米纤维膜。讨论了粒子与聚丙烯腈纳米纤维的作用方式,并通过测试证明了通过先改性后鳌合的方法能够得到表面负载均匀分散纳米粒子的无机/有机纳米材料,与传统简单掺杂纺丝的制备方法相比,避免了粒子聚集和包裹在纤维内的可能,为更好的提高应用性质打下了坚实基础。最后,分别研究了两种复合纳米纤维膜在催化亚甲基蓝褪色及Heck反应中的应用。结果表明Ag/PAN复合纳米纤维膜在7 min内即可完成亚甲基蓝的催化反应；表面负载Pd纳米粒子的聚丙烯腈复合纳米纤维作为催化剂对Heck芳基化反应的催化能力很高,反应后复合纤维膜仍然能够保持形态的完整,可以直接从反应液中分离、回收,重复使用五次后,得到反式3-苯基丙烯酸甲酯的产率为70.60%。在论文的第三章,我们将静电纺丝技术与化学改性、气固反应等方法相结合,制备出了三种附着不同无机硫化物的有机纳米复合纤维膜(CuS, PbS,Ag2S),详尽的研究了气固反应合成CuS, PbS, Ag2S纳米粒子的生长情况以及无机粒子在纳米纤维上的分布情况。并研究了三种无机／有机纳米纤维膜在可见光区范围内对亚甲基蓝的光催化降解作用,发现,三种复合膜均可以在120 mmin内将亚甲基蓝完全降解。论文第四章旨在制备一种同时具有吸附及可见光催化性质的纳米复合材料。通过将静电纺丝技术与化学改性、高温碳化、简单掺杂等方法相结合得到了ZnO-SnO2/β-CD/PAN-co-AA纳米纤维膜。这种材料可以在吸附染料的同时将其降解,提高了可见光催化降解的效率。通过对反应体系中亚甲基蓝含量的测量发现,与单纯的ZnO-SnO2纳米粒子相比,ZnO-SnO2/β-CD/PAN-co-AA纳米复合材料对亚甲基蓝有更好的吸附和催化效果,可以在60 min内将其完全降解,环糊精的吸附作用在可见光催化工程中起到非常重要的作用。在论文的第五章,我们对传统的单喷头静电纺丝技术进行改性,开发了多喷头独立电场静电纺丝法,将微米纤维引入到纳米纤维薄膜中,通过调节注射泵流速来控制膜中两种类型纤维的质量比。本章考察了不同微米纤维添加质量对整个纤维膜机械性能的影响。结果发现纤维膜的机械性能随膜中微米纤维数量的增加而增加,当微米纤维膜与纳米纤维膜的质量比为3：1时,微-纳米纤维膜的拉伸强度是单一纳米纤维膜4.50倍,在此基础之上,进一步提高纤维的取向,可使拉伸强度再提高7.96倍。另外,我们还通过双喷头电纺丝法构筑了具有机械性能增强的pH微-纳米复合变色纤维膜,与单一的纳米变色纤维相比,复合变色纤维膜膜的变色性质基本没有受到影响,而微米纤维的添加使膜的拉伸强度由1.30MPa显著提高到6.90 MPa。这种多喷头静电纺丝技术克服了单一喷头纺丝产率低的缺点,为今后的大规模生产提供了可能。更多还原

【Abstract】 With the development and advancement of nanotechnology, nano-material became indispensable in the present society because of the unique property and application compared to traditional material. Among preparation methods, electrospinning as a newly developed technique has attracted greet attention from researchers. However, with the development of electrospinning technique and society, simplex nanofiber cannot meet the need of reality. Inorganic/organic nanocomposites which have wild applications in electronics, medicine, catalyze, environmental protection etc., are the hotspot in material research. But excellent property often requires a uniform size and homogeneous distribution throughout a suitable substrate. So control over agglomeration is a key point in the preparation of particles.In the second chapter of this dissertation, electrospinning technique is employed to fabricate PAN nanocomposite film. We analyzed the effect of concentration of precursor to the morphology of nano-products, observed the process from nanoparticle to nanofiber according to the increasing of the solution concentration. Furthermore, PAN nanofiber with uniform diameter was surface modified to obtain amidoxime group, which has the ability to adsorb metal nanoparticles. Finally, Ag/PAN, Pd/PAN nanocomposite film was prepared. The combinative method between nanoparticles and PAN nanofiber has been discussed in this chapter. We find that almost all of the nanoparticles were attached on the surface through chelating effect. This method will be propitious to prevent nanoparticles from aggregation. Further more, we examined the ability of these nanocomposite films to promote the reduction reaction of methylene blue (MB) dye and Heck reaction respectively. They have excellent catalyze properties, and easy for catalyst recovery and recycle also.In the third chapter of this dissertation, we fabricate three kind of inorganic nanoparticles (Ag2S, CuS, PbS) on the surface of PAN nanofiber by combining electrospinning and gas-solid reaction. Investigate the formation, distribution and visible light photocatalytic activity of inorganic nanoparticles.The focus of the fourth chapter has been on fabrication of inorganic/organic nanofiber film with adsorption and photocatalytic degradation simultaneous. ZnO-SnO2/β-CD/PAN-co-AA nanocomopsite film is obtained via electrospinning combined with chemical modification, high temperature carbonization, simple doping and so on. It finds that adsorption has positive role for the efficiency of this photocatalyst. ZnO-SnO2/β-CD/PAN-co-AA nanocomopsite film showed much higher adsorption and catalyzes ability to elimination of MB than ZnO-SnO2 nano-heterostructure.In the fifth chapter of this dissertation, we improve the traditional electrospinning technique to employ a multi-nozzle electrospinning setup. Nanofiber from the one nozzle and micro-sized fiber from the other nozzle were combined homogeneously by two-nozzle electrospinning. Microfiber plays the role of support which is favorable for enhancing the mechanic performance of the film. As a result, the weak intensity problem of membrane is effectively resolved by this advanced electrospinning technique. The result shows compared with film composed by simplex nanofiber, the tensile strength of the composite fiber film contain nanofiber and microfiber simultaneity has been enhanced by a factor of 4.54. After further improve orientation of composite fiber, the tensile strength is 30.00 times that of simplex nanofiber. Furthermore, this technique has been used to prepare pH-sensitive films with enhanced mechanical property. The results show that the pH sensitive film that merely consist with PAN nanofiber or composite PAN/PA-6 fiber all exhibited remarkable color change from pale yellow to violet in a wide range of alkaline solutions and rapid response time within 100 S. But after microfibers added, the tensile strength of mat was enhanced from 1.30 MPa to 6.90 MPa prominently which is beneficial to put the mats into practice.更多还原