infrared, NMR, and elemental analysis. Three series of polyimides (PIs) were prepared from the obtained isomeric dianhydrides and aromatic diamines in N‐methyl‐2‐pyrrolidone (NMP) via the conventional two‐step method. The PIs showed excellent solubility in common organic solvents such as chloroform, N,N‐dimethylacetamide, and NMP. Their glass‐transition temperatures decreased according to the order of PIs
三种异构的双(
硫醚酐)单体,4,4'-双(2,3-二羧基苯
硫基)二苯基酮二酐(3,3'-
PTPK
DA),4,4'-双(3,4-二羧基苯
硫基)二苯基酮二酐通过多步反应制备了(4,4'-
PTPK
DA)和4-(2,3-二羧基苯
硫基)-4'-(3,4-二羧基苯
硫基)二苯基酮二酐(3,4'-
PTPK
DA)。它们的结构是通过傅立叶变换红外光谱,NMR和元素分析确定的。通过常规的两步法,从N-甲基-
2-吡咯烷酮(
NMP)中获得的异构体二酐和芳族二胺制备了三个系列的聚
酰亚胺(
PI)。
PI在普通有机溶剂(如
氯仿,N,N)中显示出极好的溶解性-二甲基乙酰胺和
NMP。在3,3'-
PTPK
DA,3,4'-
PTPK
DA和4,4'-
PTPK
DA的基础上,它们的
玻璃化转变温度根据
PI的顺序降低。在504–519°C的温度下,所有
PI在氮气中的失重温度均为5%(T 5%)。与4,4'-和3,4'-的相应异构体相比,基于3