聚苯胺基热电复合材料的制备及热电性能研究

发布时间：2018-03-25 05:28

本文选题：热电材料　切入点：热电复合材料　出处：《浙江理工大学》2017年硕士论文

【摘要】：热电材料是一类利用固体内部载流子的移动来实现电能和热能相互转化的材料,在温控、温差发电、汽车尾气和工业余热的回收利用等领域具有非常广阔的应用前景。聚合物材料具有本征低热导率,很好的溶液加工性能,原材料来源丰富、价格低廉等优势,因而引起了热电领域研究者们的广泛关注。其中聚苯胺作为一种易合成、易加工的导电聚合物,被认为是最具有发展潜力的聚合物热电材料之一。然而,目前聚苯胺材料的热电性能还远远达不到实际应用要求。为进一步提升聚苯胺热电性能,以达到实际应用目标,将其作为基体,引入高性能低维纳米材料制备复合材料来优化材料的热电性能成为目前的研究热点。本文以碳纳米管(CNTs)和还原态氧化石墨烯(RGO)作为填充模板,以导电聚合物聚3,4-乙烯二氧噻吩:聚苯乙烯磺酸(PEDOT:PSS)作为分散稳定物质均匀的分散填充物,再采用化学原位聚合的方式合成有序分子链结构的PANI进而制得三种复合材料即CNTs/PEDOT:PSS/PANI,RGO/PEDOT:PSS/PANI与CNTs/RGO/PEDOT:PSS/PANI。采用XRD、FE-SEM对复合材料的结构进行表征,并测试了复合材料的电导率、Seebeck系数、热导率等热电性能参数。同时,本文也探究了填充物(CNTs/RGO)与PEDOT:PSS的比例,填充物CNTs与RGO的比例及填充物含量对材料热电性能的影响,得出以下结论:(1)在CNTs/PEDOT:PSS/PANI复合材料中,PEDOT:PSS作为分散稳定物质,随着其与CNTs比例的的提升,CNTs分散程度得以提升,复合材料热电性能得到一定程度的提升。当CNTs与PEDOT:PSS的比例达到1:4时,最大ZT值为1.21×10-6。随着CNTs含量的提升,填充物接触距离减小,利于载流子传输,提升电导率。同时,由于复合材料界面的能量渗滤效应和声子散射效应,提升了Seebeck系数,降低了热导率,进而提升了ZT。CNTs含量为50%时,最大值ZT为2.09×10-5,相对于纯的PANI提升了约31倍。(2)采用原位聚合的方式制备RGO/PEDOT:PSS/PANI复合材料。随着RGO的提升,复合材料引入更大的界面区域,能量渗滤效应增强,有效提升了Seebeck系数,而填充含量的增加也可促进电导率的提升,最终热电性能得以提升。当RGO含量为50%时,复合材料的最大ZT值为7.25×10-6,相比于纯的PANI提升了约10.5倍。(3)采用原位聚合的方式制备CNTs/RGO/PEDOT:PSS/PANI复合材料。一维的CNTs与二维的RGO之间有强烈的相互作用,进而引发协同效应。当CNTs与RGO的比例为2:1时,协同效果较为明显。随着填充物(CNTs/RGO)含量的提升,复合材料的电导率、Seebeck系数及ZT也随之提升。当填充物含量为50%时,一维/二维协同复合材料的最大ZT值为2.38×10-5,与CNTs含量为50%的CNTs/PEDOT:PSS/PANI相比,提升了约1.2倍,与RGO含量50%的RGO/PEDOT:PSS/PANI相比,提升了约3.3倍,而相对于PANI提升了约36倍。
[Abstract]:Thermoelectric materials are a kind of materials that use the movement of carriers in solids to realize the mutual conversion of electric energy and heat energy. The application prospect of automobile exhaust gas and industrial waste heat recovery is very broad. Polymer materials have the advantages of intrinsic low thermal conductivity, good solution processing performance, abundant raw material sources, low price, etc. As a kind of conductive polymer, Polyaniline is considered as one of the most potential polymer thermoelectric materials. At present, the thermoelectric properties of Polyaniline materials are still far from the practical application requirements. In order to further improve the thermoelectric properties of Polyaniline in order to achieve the practical application goal, the Polyaniline is used as the matrix. In order to optimize the thermoelectric properties of high performance low-dimensional nanocomposites, CNTsand reduced graphene oxide (RGOO) were used as filling templates. A conductive polymer, poly (3o 4-ethylenedioxythiophene): polystyrene sulfonic acid (PEDOT: PSS), was used as a uniform dispersive filler with stable dispersion. Then the PANI with ordered molecular chain structure was synthesized by chemical in-situ polymerization, and three kinds of composites, CNTs / PEDOT: PSSP / PSSP / PSSP / PSSP / pani and CNTsR / RGOP / PEDOT / PSSP / PANI, were prepared. The structure of the composites was characterized by XRDX FE-SEM, and the conductivity of the composites was measured by Seebeck coefficient. At the same time, the ratio of filler CNTs / RGO to PEDOT:PSS, the ratio of filler CNTs to RGO and the effect of filler content on the thermoelectric properties of the material were also investigated. The following conclusion is drawn: (1) in CNTs/PEDOT:PSS/PANI composites, PEDOT: PSS is used as a dispersion stabilizer. The thermoelectric properties of CNTs/PEDOT:PSS/PANI composites are improved to a certain extent with the increase of the ratio of CNTs to CNTs. When the ratio of CNTs to PEDOT:PSS reaches 1:4, The maximum ZT value is 1.21 脳 10 ~ (-6). With the increase of CNTs content, the contact distance of the filler decreases, which is beneficial to carrier transport and increase the conductivity. At the same time, the Seebeck coefficient is increased because of the energy percolation effect and phonon scattering effect at the interface of the composite. When the content of ZT.CNTs is 50, the maximum ZT value is 2.09 脳 10 ~ (-5), which is about 31 times higher than that of pure PANI, and the RGO/PEDOT:PSS/PANI composite is prepared by in-situ polymerization. With the increase of RGO, the interface area of the composite is larger. The energy percolation effect is enhanced, the Seebeck coefficient is increased effectively, and the electrical conductivity is promoted by the increase of the filling content. Finally, the thermoelectric properties are improved when the RGO content is 50. The maximum ZT value of the composite is 7.25 脳 10 ~ (-6), which is about 10.5 times higher than that of pure PANI.) CNTs/RGO/PEDOT:PSS/PANI composites are prepared by in-situ polymerization. There is a strong interaction between one-dimensional CNTs and two-dimensional RGO. When the ratio of CNTs to RGO is 2:1, the synergistic effect is obvious. With the increase of the content of CNTs / RGO, the conductivity and ZT of composites also increase. The maximum ZT value of one-dimensional / two-dimensional synergistic composites is 2.38 脳 10 ~ (-5), which is about 1.2 times higher than that of CNTs/PEDOT:PSS/PANI with 50% CNTs content, 3.3 times higher than RGO/PEDOT:PSS/PANI with 50% RGO content, and 36 times higher than that of PANI.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34

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