【作者】 仇海珍；

【导师】 李良超；

【作者基本信息】 浙江师范大学 ， 有机化学， 2009， 硕士

【摘要】 近年来,具有磁行为的导电聚合物和含有导电聚合物的磁性纳米微粒的合成已引起了人们极大的关注。在众多导电聚合物中,聚苯胺(PANI)由于电导率高、质轻、掺杂态和未掺杂态的环境稳定性好、易于制备、单体的成本低等优点,已在防静电、微波吸收、电磁屏蔽等领域具有广泛的用途。但聚苯胺的难溶和难加工性使其应用受到限制,而聚取代苯胺则是解决以上问题的可能途径之一。取代苯胺是指苯环上的氢原子或氨基N原子上的氢被其他基团(烷基,烷氧基,卤素等)所取代,其性质随取代基的类型而异,且取代基的影响能够弥补聚苯胺在应用技术上的不足。如果将具有电损耗功能的聚苯胺或取代聚苯胺与具有磁损耗功能的铁氧体进行适当的复合,就有可能使该复合材料在保持各个组分材料某些特点的基础上,具有组分间协同作用所产生的综合性能。并可以通过调节各组元的相对含量实现对复合材料电磁性能的调控,弥补了单一材料的缺点,为制备电磁屏蔽、电磁波损耗吸收剂等功能材料和拓宽材料的应用领域提供了新的发展空间。基于上述目的,本论文将锌锰镍软磁铁氧体与取代聚苯胺(苯胺)复合,以期能够在拓宽其应用范围的前提下进一步提高复合材料的电磁损耗性能。本论文用化学共沉淀法制备了锌锰镍铁氧体(ZMNFO)纳米粉末,用原位聚合法制备了苯胺/氯代苯胺的共聚物(PAn-co-P2ClPAn)、聚邻甲基苯胺(POT)、聚N-甲基苯胺(PNMAn)及其与锌锰镍铁氧体的各种复合物PAn-co-P2ClPAn/ZMNFO、POT/ZMNFO和PNMAn/ZMNFO。用X-射线衍射仪(XRD)、红外光谱(FT-IR)、热重(TG)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)分析了样品的微结构,微观形貌和热稳定性。实验结果证实了复合物是由导电聚合物和铁氧体纳米粒子组成的具有核-壳结构的复合体系。磁性纳米粒子的引入提高了复合物的热稳定性。用四探针电导率仪、振动样品磁强计(VSM)和阻抗/材料分析仪分别测定了样品的导电率、饱和磁化强度和矫顽力以及复介电常数和复磁导率,计算了样品的电损耗因子tanδ_e和磁损耗因子tanδ_m。结果表明:复合物的导电率比聚合物小,且随铁氧体含量的增加而减小,其主要原因是铁氧体几乎为绝缘性粒子,铁氧体含量的增加降低了聚合物共轭链的连续性和掺杂度,导致复合物的导电性降低;复合物的饱和磁化强度随着磁性粒子含量的增加而增大,而矫顽力较小且变化不大;复合物以磁损耗为主,由于磁含量小,磁损耗正切值tanδ_m比纯铁氧体小,且随着磁含量的增大而增大。此外,复合物也有较好的介电损耗性能,且tanδ_e。值出现了比纯聚合物大的现象,说明复合物的双组元间有较强的相互作用,其协同效应使介电损耗增大。更多还原

【Abstract】 In the recent years,the synthesis of conductive polymers with the magnetic behavior and the magnetic nano-particles including conductive polymers has attracted people great attentions.Among the whole conducting polymers,polyaniline（PAn） has a specific situation because of its simply synthesis,environmental stability,low price,light mass and doping with protonic acids and can be widely used in such fields as antistatic conductive,microwave absorption,electromagnetic shielding and so on.However,the major disadvantage of PAn is its insolubility in common organic solvents and its infusibility because of the strongπconjugate action.There are some possible methods for preparing soluble PAns.One of these methods is to substitute one or more hydrogens by an alkyl,an alkoxy,an amino group,or halogen on the benzene ring or -N atom.Different substituted anilines have different properties and they can remedy the defects of polyaniliane.So compounding the polyaniline or poly substituted-aniline with ferrite by proper ways will provide the composites a better comprehensive performance and the original characteristic of constituents be kept.Adjusting the composition of composites has an effect on the electromagnetic properties of composites and can make up for the deficiency of single component ferrite and polymers.So this method brought the more vast development space for the practical application of electromagnetic materials.Desiring the above purposes,we prepare the substituted polyaniline and substituted polyaniline/Zn_0.6Mn_0.2Ni_0.2Fe₂O₄ composites and wish to improve the electromagnetic loss properties of composites under the premise of widen their application range.In this article,the Zn_0.6Mn_0.4-xNixFe₂O₄（x=0.1,0.2,0.3,0.4） magnetic particles were prepared by the chemical coprecipitation and the Zn_0.6Mn_0.2Ni_0.2Fe₂O₄（ZMNF） was used to prepared composites.The copolymers（aniline-co-2chloroaniline） （PAn-co-P2ClPAn）,poly（o-methylaniline）（POT）,poly（N-methylaniline）（PNMAn）, polyaniline（PAn） and their composites（polymer/ZMNF） with different ZMNF mass fraction were synthesized by in-situ aqueous polymerization.The structure of samples was characterized by X-ray diffraction（XRD） Fourier transform infrared spectra（FT-IR）,and the particle sizes and morphologies of samples were observed by transmission electron microscopy（TEM） and scanning electron microscopy（SEM）.The thermal stability of samples was measured by thermogravimetric analysis（TANA）.The results revealed that the ferrite particles were wrapping well by polymers and form the core-shell structure,and the incorporation of ferrite improved the thermal stability of composites.The conductivity,saturation magnetization and electromagnetic loss parameters （tanδ_m,tanδ_e） of samples were measured.The results indicated that the conductivity of composites decreased with reduction of the conducting polymer content.The reason is that the continuity and doping degree of plymers decrease with the increase content of the hardly insulating ZMNF.The saturation magnetization decreases were lower than that of pure ferrite,and decreased with decreasing of ZMNF content.Moreover their coercive force was very little.In addition,the results showed that the tanδ_m decrease with the decreasing of ZMNF content,which was related to the volume fraction of ferrite particles.The results showed tanδ_e in some composites was larger than pure polymers,which applied a coordinate effect occurred between polymers and ZMNF particles.This indicated that the composites exhibited the strong interfacial polarization between polymers and ZMNF particles.And the interfacial interaction changed with the content change of polymers.更多还原