BPDA/ODA和PMDA/ODA共混聚酰亚胺薄膜

采用3,3′,4,4′-联苯四甲酸二酐/4,4′-二氨基二苯醚（BPDA/ODA）和1,2,4,5-均苯四甲酸二酐（PMDA）/ODA聚酰胺酸共混的方法制备了聚酰亚胺（PI）薄膜，研究了共混体系中共混比对薄膜的力学性能、动态力学性能、介电性能等的影响。用万能材料试验机、动态力学分析仪和阻抗分析仪研究了其力学性能、热性能和电性能与共混比例之间的关系。结果表明，这种共混PI薄膜可以保持良好的力学性能，特别是当选择了合适的共混比例时，PI薄膜的断裂伸长率会得到明显的提高，同时仍然保持其良好的耐热性能，介电损耗陡升温度在250 ℃以上，有望在240级以上漆包线的生产中得到广泛应用。

Fabrication and Performance Investigation of Polyimide Film by Blending BPDA/ODA and PMDA/ODA

A new type of polyimide material was prepared via a blending method utilizing BPDA/ODA and PMDA/ODA polyamide acid as precursors. The relationship of the mechanical, thermal and electric properties of the derived material and the blending ratio was also investigated. Universal material testing machine, dynamic mechanical analysis and precision impedance analyzer were employed during the optimization of the blending ratio which associated closely with the physicochemical properties mentioned above. The characterization indicated that the elongation at break of the blended polyimide could be significantly improved by simply using a suitable blending ratio, meanwhile without compromising its good heat resistant property. The temperature at the turning point for dielectric loss rapid rise was above 250 ℃. This kind of material was very promising in wide application of manufacturing the enameled wire leveled above 240.