低介电聚倍半硅氧烷/聚酰亚胺共聚膜的制备与性能表征

Preparation and characterization of low dielectric polysiloxane/polyimide copolymer films

通过水解缩合法制备末端为氨基的多面体低聚倍半硅氧烷(NH_(2)-POSS),并以此多面体低聚倍半硅氧烷(NH_(2)-POSS)作为聚酰亚胺的“二胺”,混合4,4′-二氨基二苯醚(ODA),均苯四甲酸二酐(PMDA)为二酐,以原位聚合法制备二元共聚聚酰胺酸溶液(PAA)。以二分法确定了NH_(2)-POSS在共聚PAA溶液中提供的氨基比例,通过热亚胺化制备成膜。探究了不同比例下NH_(2)-POSS对共聚膜的性能影响,通过红外光谱、热重分析仪、万能试验机和宽频介电阻抗谱仪对共聚膜进行性能表征。结果表明:共聚膜具有媲美纯聚酰亚胺膜的热稳定性(545℃,5%)和力学性能(拉伸强度90~122MPa),并且具有更低的介电常数(25%POSS-PI膜,106Hz介电常数2.8)。

In order to prepare flexible self-supporting lithium battery anode carbon nanofiber films,solutions of polypyrrolones and polyimide precursors with different concentrations were mixed,and the flexible fiber films were analyzed by surface morphology observation,structural characterization,and electrochemical testing using electrospinning and high-temperature carbonization techniques.The results showed that due to the structural similarity between polypyrrolone and polyimide,they had good compatibility.The nanofiber films exhibited excellent flexibility after imidization and carbonization in nitrogen atmosphere,and could be directly used as lithium self-supporting anode material.When the mass ratio of polypyrrolone to 9wt%polyimide was 85∶15 and the current density was 50mA/g,the discharge specific capacity of 378.7mAh/g was still available after 100 cycles.