Detection of propagating radicals in the radical polymerization and estimation of their redox potentials.

自由基聚合是高分子化学中最成熟的领域之一，对乙烯基化合物的自由基聚合已经进行了大量的研究，然而，本文报道了用电子自旋共振（ESR）谱研究自由基传播过程中的物理化学性质的方法，并成功地测定了自由基传播过程的ESR谱本文利用新型空穴反应器研究了乙烯基化合物自由基聚合中的增长自由基：在室温下直接观察到乙酸异丙烯酯和乙烯基醚的增长自由基的ESR谱，并根据增长自由基的结构讨论了这些单体不能用自由基引发聚合得到高聚物的原因。此外，ESR研究还发现了有关增长自由基物理化学性质的新信息，但由于ESR谱仪的灵敏度随着测量氧化还原电位的仪器的安装而降低，我们无法成功地估算增长自由基的氧化还原电位。

The radical polmerization is one of the most established fields in polymer chemistry,and a lot of studies have been carried out on the radical polymerization of vinyl compounds.However,problems still remain unsolved on the physicochemical propeties of the propagating radicals.The ESR spectroscopy has been considered to be one of the potential method for the clarification of these problems.we succeeded on the detection of the ESR spectra of the transient species in the radical polymerization of vinyl compounds by using the new type of cavity:the ESR spectra of the propagating radicals of isopropenyl acetate and vinyl ethers,which did not polymerize to high polymer,were observed directly at room temperature.Accordingly, reason why high polymers could not be obtained from these monomers by radical initiators was discussed on the basis of the structure of the propagating radicals. In addition,new information on the physicochemical property of the propagating radicals was found in the ESR studies.However,we could not succeeded in the estimation of the redox potentials of the propagating radicals,because the sensitivity of the ESR spectrometer decreased with mounting the instrument for the measurements of the redox potentials.