ELECTRONIC CONDUCTION IN POLYMERS .2. ELECTROCHEMICAL REDUCTION OF POLYPYRROLE AT CONTROLLED POTENTIAL
ELECTRONIC CONDUCTION IN POLYMERS .2. ELECTROCHEMICAL REDUCTION OF POLYPYRROLE AT CONTROLLED POTENTIAL
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DOI：
10.1071/ch9631076
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发表时间：
1963-01-01
影响因子：
1.1
通讯作者：
WEISS, DE
中科院分区：
文献类型：
--
作者：
BOLTO, BA;WEISS, DE
采用汞阴极电化学还原法从聚吡咯中除去分子碘。发现该方法比刚性或填充聚合物电极的处理更有效。 伏安图表明，发生两个减少，在电位pH值不敏感。电流通道是依赖于碘含量，而部分减少或溶剂萃取删除的第一个电流峰。完全还原或碱处理消除了这两个峰，而碘在溶液中增加还原电位。根据这一证据，推测第一个峰是由于溶液中的碘，第二个峰是由于碘作为聚吡咯的电荷转移络合物存在。通过估计电解质中存在的碘和碘化物的量，计算溶解碘的还原电位，发现与浆料还原中的第一个峰所观察到的一致。通过还原含有测定量碘和碘化物的空白溶液，证实了该可能性。 获得了中性电解质中浆料还原的定量数据。在对已经存在的碘化物进行校正后，库仑法估计值与去除的碘之间存在合理的一致性，前提是阳极反应不向阴极电解液提供可还原材料。在中性悬浮液中，聚吡咯本身对碘的还原作用并不显著。 碘很容易从早期的聚合物中电化学除去，其含量仅为约2.2 m-equiv/g。后来的聚合物含有几乎三分之一以上的碘，并需要延长还原时间，这是通过使用银阳极在碘离子形成时清除碘离子而大大缩短的。还原产物的酸度，电阻率和氧含量的变化进行了比较。I.
Molecular iodine was removed from polypyrrole by electrochemical reduction of slurries at a mercury cathode. This method was found to be more effective than the treatment of rigid or packed polymer electrodes. Voltammetric plots indicated that two reductions occurred, at potentials insensitive to pH. The current passage was dependent on the iodine content, while partial reduction or solvent extraction deleted the first current peak. Complete reduction or alkali treatment removed both peaks, whereas iodide in solution increased the reduction potentials. From this evidence it is postulated that the first peak is due to iodine in solution, the second to iodine present as a charge-transfer complex of polypyrrole. By estimating the amount of iodine and iodide present in the electrolyte the reduction potential for dissolved iodine was calculated and found to agree with that observed for the first peak in the slurry reduction. Confirmation of this potential was obtained in the reduction of a blank containing the found amounts of iodine and iodide. Quantitative data were obtained for the reduction of slurries in neutral electrolytes. There was reasonable agreement between coulometric estimations and the iodine removed, after correction for iodide already present, provided that the anode reaction did not supply reducible material to the catholyte. Reduction of iodine by polypyrrole itself did not appear significant in neutral suspensions. Iodine was readily removed electrochemically from the early polymers which contained only about 2.2 m-equiv/g. A later polymer contained almost a third more iodine and required prolonged reduction times which were cut considerably by the use of a silver anode to mop up iodide ion as it was formed. The reduction products were compared for changes in acidity, resistivity, and oxygen content. I.