热熔型聚酰亚胺薄膜的热封性能研究

针对现有商用聚酰亚胺（PI）薄膜无法采用热熔工艺进行粘接的问题，采用异构化二酐单体、2，3，3’，4’-二苯醚四酸二酐（a-ODPA）分别与7种芳香族二胺单体通过化学亚胺化工艺制备了PI薄膜（PI-1～PI-7），系统研究了这些PI薄膜的结构与性能的关系。结果表明:a-ODPA的不对称结构赋予了PI薄膜良好的热塑性特征，使之可以采用热熔工艺进行粘接，薄膜间的热封强度最高可达660 N/m；此外，制备的PI薄膜还具有良好的耐热性能与力学性能，5%失重的温度超过500℃，玻璃化转变温度超过230℃，薄膜拉伸强度超过89 MPa。

The heat sealability of melt-processable polyimide films

A series of melt-processable polyimide （PI） films are developed to solve the problem of the infusibility of the commercially available PI films. Seven PI films （PI-1-PI-7） are synthesized from an asymmetrical aromatic dianhydride, 2,3,Y,4＇-oxydiphthalic dianhydride （a-ODPA） and various aromatic diamines via a chemical imidization procedure. The structure-property relationships of the PIs are investigated. It is shown that the asymmetrical structure of a-ODPA gives the derived PIs a good thermoplasticity and the PI films could be adhered via a heat-sealing procedure. The adhesive strength between the PI films could reach a maximum value of 660 N/m. In addition, the prepared PI films show good thermal and mechanical properties with 5% weight loss temperatures over 500 ℃, glass transition temperatures higher than 230 ℃ and tensile strengths over 89 MPa.