An Increase in Breakdown Strength of Polymeric Film by Addition of Aromatic Compound

研究了添加以下芳香族化合物提高低密度PE薄膜的击穿强度；蒽（As）， 9,10-二溴蒽（Br_As），苝（Pr），苝- 3,4,9,10四羧基二氢化物（Tc_Pr）。薄膜厚度为6μm ~ 18μm。实验结果表明，这些添加剂的加入提高了材料的直流击穿强度。添加As的薄膜在室温下的击穿强度约为未添加As的薄膜的1.45倍，室温下击穿强度为6MV/cm。含有电子受体自由基分子的添加剂的薄膜的击穿强度比不含自由基的添加剂的薄膜的击穿强度高。通过测量薄膜的TSC和DSC来研究载流子陷阱位置的条件。此外，还研究了该化合物的加入对PE膜高阶结构的影响。添加添加剂的膜的TSC峰值出现在4℃左右，比未添加添加剂的膜的TSC峰值高。当化合物加入到薄膜中时，峰值电流的值提高了3倍。在添加和不添加添加剂的情况下，负电荷的陷阱深度分别为4.5eV和3eV。DSC结果表明，添加剂对薄膜高阶结构变化的影响不显著。添加剂的紫外吸收光谱也表明，添加剂的芳香族化合物内π电子的激发对薄膜击穿强度的提高没有重要作用。我们得出结论，本研究中使用的添加剂对PE薄膜击穿强度的提高是由于添加剂分子中载流子陷阱的作用。

An increase in breakdown strength of low density PE film was studied using additives of following aromatic compounds ; Anthracene (As), 9,10-dibromo anthracene (Br_As), Perylene (Pr), and Perylene3,4,9,10tetracarboxylic-diahhydride (Tc_Pr). Thickness of the film ranges from 6μm to 18μm.The experimental results indicate that dc breakdown strength is increased using these additives. The breakdown strength for the film with As at room temperature is about 1.45 times higher than that of the film without additive, which has 6MV/cm at room temperature. The breakdown strength for the film with additive of which molecule involves an electron acceptor radical is higher than that for the film with additive without the radical.TSC and DSC of the films were measured to investigate the conditions of the carrier trap site. Furthermore, influences of addition of the compound upon higher-order structure of the PE film were investigated. Peak of the TSC for the film with additive appears at about 4℃ higher than that for the film without additive. The value of the current at the peak is 3 times higher when the compound is added to the film. The depths of the trap for the negative charge are estimated to 4.5eV and 3eV in the cases of the films with and without additive, respectively. The results of DSC indicate that an influence of additive upon the change in higher-order structure of the film is not significant.UV absorbance spectrum for the additive also suggested that the excitation of π-electrons within the aromatic compound of additive is not play an important role to the increase in breakdown strength of the film.We concluded that the increase in breakdown strength of PE film by additive used in this study results from the effect of carrier trap in the molecule of the additive.