磁场对聚苯胺结构、掺杂行为及热稳定性的影响

Effect of a magnetic field on structure,doping characteristics and stability of polyaniline

在恒定磁场(0.8T)和无磁场环境下,采用化学氧化聚合法合成了分别用磺基水杨酸(SSA)、对甲基苯磺酸(TSA)以及用十二烷基苯磺钠/盐酸(SD-BS+HCl)掺杂的聚苯胺盐,并采用X射线光电子能谱(XPS)、傅立叶红外光谱(FT-IR)、X粉末衍射(XRD),热重分析(TGA)等手段研究了磁场对聚苯胺结构、掺杂行为及热稳定性的影响。结果表明在合成聚苯胺的过程中,作为表面活性剂的十二烷基苯磺酸钠在无机酸存在条件下转变成十二烷基苯磺酸并与无机酸共同掺杂进入聚苯胺链;磁场环境下合成的聚苯胺盐比无磁场下合成的聚苯胺盐的链更加规整,热稳定性更好,掺杂程度以及结晶性能也有所提高;从红外光谱分析中可知,磁场取向作用使分子链更加伸展,分子链离域程度更大,但磁场没有明显地改变聚苯胺的基本单元结构。

Polyaniline（PAN） salts doped with functionalized sulfonic acids such as sulfosalicylic acid（SSA）,toluenesulfonic acid（TSA）,hydrochloric and sodium dodecylsulfate（HCI＋ SDBS） as the dopants were synthesized by chemical oxidative polymerization method using ammonium persulfate（APS） as an oxidizing agent under the presence and the absence of a constant magnetic field（0.8T）. The structure, doping characteristics and thermal stability of these salts were investigated using X-ray photoelectron spectroscopy（XPS）,FT-IR spectroscopy, X- ray diffraction（XRD） and Thermogravimetric analysis（TGA）. The result showing that the surfactant SDBS used in the synthesis of PAN salts gets converted to the dodecyl hydrogen sulfate under acidic conditions and doped onto the PAN backbone along with the mineral acid. In comparison with the corresponding PAN salts synthesized under the absence of the magnetic field, the PAN salts synthesized under the presence of the magnetic field are found to have higher doping degree and the thermal stability as well as crystallinity are also greater.