首先合成了同时含有砜基与硫醚键的二胺单体,4,4′-双(4-胺基苯硫基)二苯砜(BADPS)。采用BADPS分别与4种二酐单体,3,3′,4,4′-联苯四羧酸二酐(BPDA)、3,3′,4,4′-二苯醚四羧酸二酐(ODPA)、4,4′-双(3,4-二羧基苯硫基)二苯硫醚二酐(3SDEA)以及1,2,3,4-环丁烷四羧酸二酐(CBDA)通过两步聚合工艺制备了一系列聚酰亚胺(PI)。制备的PI薄膜具有优良的综合性能,包括良好的热稳定性、可见光波长范围内优良的透明性以及高折射率与低双折射。10mm厚的PI薄膜在450nm处的透光率超过80%。全芳香族PI(PI-1~PI-3)的折射率〉1.70,双折射〈0.02。
An aromatic diamine containing sulfone and thioether bonds, 4,4-bis(4-amino-phenylenesulfanyl)diphenylsulfone (BADPS) was synthesized first. The diamine was polymerized with four dianhydrides, 3,3′,4,4′- biphenyltetracarboxylic acid dianhydride (BPDA), 4,4′-oxy-diphthalic anhydride (ODPA), 4,4′-bis (3,4-dicarboxyphenylenesulfanyl) diphenylthioether dianhydride (3SDEA), and 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride (CBDA), respectively via a two-step polycondensation procedure to afford a series of polyimides (PIs). The obtained PIs exhibited good combined properties, including good thermal stability, high optical transparency in the visible light region, and high refractive indices and low birefringence. The wholly aromatic PIs (PI-1 to PI-3) had refractive indices higher than 1.70 and birefringence lower than 0.02.