Structures and properties of chemically reduced polyanilines
Structures and properties of chemically reduced polyanilines
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DOI：
10.1016/s0032-3861(97)00381-9
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发表时间：
1998-03-01
期刊：
影响因子：
4.6
通讯作者：
Ko, TM
中科院分区：
文献类型：
--
作者：
Zeng, XR;Ko, TM
以重铬酸钾为氧化剂，在盐酸水溶液中，通过苯胺的氧化聚合反应，合成了盐酸掺杂翠绿亚胺型聚苯胺（PANI-H）。使用肼作为还原剂化学还原未掺杂形式的PANI-H（即PANI）。采用元素分析、红外光谱、热重分析等方法对还原态聚苯胺（PANI-R）的结构、掺杂、导电性和热稳定性进行了研究。固态C-13-NMR、XPS和TGA。发现PANI中的醌型结构单元大多被还原为苯环型结构单元。用HCl和碘对PANI-R进行掺杂，但只有碘掺杂的产物（PANI-RI）显示出高的电导率。傅立叶变换红外光谱仪XPS结果表明，在碘掺杂过程中，PANI-R分子链中的苯环结构单元被氧化为醌型结构单元，形成了高度共轭的π体系。TGA结果表明，PANI-R比PANI具有更好的热稳定性。在低于250 ℃时，掺杂剂HCl和碘几乎完全从HCl和碘掺杂的聚苯胺中除去。PANI-R也能被重铬酸钾氧化。本征氧化的PANI-R（PANI-RO）的热稳定性出乎意料地差。HCl掺杂的PANI-RO的电导率远低于HCl掺杂的PANI。(C)1997 Elsevier Science Ltd.保留所有权利。
HCl-doped emeraldine form of polyaniline (PANI-H) was synthesized by oxidative polymerization of aniline in aqueous hydrochloric acid solution using potassium dichromate as an oxidant. The undoped form of PANI-H (i.e. PANI) was chemically reduced using hydrazine as the reductant. The structure, doping, conductivity and thermal stability of the reduced polyaniline (PANI-R) were studied by elemental analysis, FT-i.r., solid-state C-13-NMR, XPS and TGA. It was found that most of the quinoid structural units in PANI were reduced to benzenoid structural units. PANI-R had been doped with HCl and iodine, but only the iodine-doped product (PANI-RI) showed high electrical conductivity. FT-i.r. and XPS results indicated that some of the benzenoid structural units in PANI-R were oxidized to quinoid structural units during the iodine-doping process and a highly conjugated pi system might be formed in the PANI-RI molecular chains. TGA results indicated that PANI-R had better thermal stability than PANI. The dopants-HCl and iodine-were almost completely removed from the HCl and iodine-doped polyanilines below 250 degrees C. PANI-R could also be oxidized by potassium dichromate. The thermal stability of the intrinsically oxidized PANI-R (PANI-RO) was unexpectedly poor. The electrical conductivity of HCl-doped PANI-RO was much lower than that of HCl-doped PANI. (C) 1997 Elsevier Science Ltd. All rights reserved.