Kwac Lee Ku, Kim Hong Gun, Chang Jin-Hae
Graduate School of Carbon Convergence Engineering, Jeonju University, Jeonju 55069, Korea.
Institute of Carbon Technology, Jeonju University, Jeonju 55069, Korea.
ACS Omega. 2021 Jul 14;6(29):19006-19016. doi: 10.1021/acsomega.1c02285. eCollection 2021 Jul 27.
To improve the optical properties of polyimide (PI) films, we prepared two series of colorless transparent PIs from the dianhydride 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and a diamine, either 2,2-bis(3-aminophenyl)hexafluoropropane (FDN) or 2,2-bis(3-amino-4-hydroxy-phenyl)hexafluoropropane (FDN-OH). Next, colorless PI (CPI) composite films were prepared by dispersing 0-1.00 wt % of organically modified clay (Cloisite 30B) in the intermediate poly(amic acid) (PAA) solution via solution intercalation, followed by imidization. The resultant CPI films had excellent optical transparency, which was achieved by reducing the charge-transfer effects by using a highly electronegative trifluoromethyl group and a kinked monomer structure. The thermal and mechanical properties, morphologies, and optical transparencies of the two as-synthesized CPI hybrid film series were investigated and compared. Electron microscopy observation of the two hybrid series revealed that the clay was well-dispersed with a nanoscale dispersion at all clay contents. However, agglomeration occurred at nanoclay loadings of 1.0 wt %. In addition, the effect of the presence of hydroxyl groups in the PI chain on various physical properties of the two CPI hybrids was also compared.
为了改善聚酰亚胺（PI）薄膜的光学性能，我们用二酐4,4'-（六氟异亚丙基）二邻苯二甲酸酐（6FDA）与二胺2,2-双（3-氨基苯基）六氟丙烷（FDN）或2,2-双（3-氨基-4-羟基苯基）六氟丙烷（FDN-OH）制备了两个系列的无色透明聚酰亚胺。接下来，通过溶液插层法在中间聚酰胺酸（PAA）溶液中分散0-1.00 wt%的有机改性粘土（Cloisite 30B），然后进行亚胺化反应，制备出无色PI（CPI）复合薄膜。所得的CPI薄膜具有优异的光学透明度，这是通过使用高电负性的三氟甲基和扭结的单体结构来降低电荷转移效应实现的。对两个合成的CPI杂化薄膜系列的热性能、机械性能、形态和光学透明度进行了研究和比较。对这两个杂化系列的电子显微镜观察表明，在所有粘土含量下，粘土都能很好地分散，呈纳米级分散。然而，在纳米粘土负载量为1.0 wt%时出现了团聚现象。此外，还比较了PI链中羟基的存在对两种CPI杂化物各种物理性能的影响。
