Kim Seong Jong, Kang Inah, Byun Taejoon, So Jongho, Kim Sang Youl
Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
Polymers (Basel). 2022 Jan 27;14(3):501. doi: 10.3390/polym14030501.
Soluble and transparent wholly aromatic polyamides (PAs) were synthesized from an unsymmetrical diamine monomer having trifluoromethyl (CF) groups, 4-(4'-aminophenoxy)-3,5-bis(trifluoromethyl)aniline. The monomer was polymerized with several dicarboxylic acid monomers via the Yamazaki-Higashi polycondensation method. All of the synthesized polyamides have an amorphous morphology, and they are soluble in many polar organic solvents at room temperature. Flexible and transparent films of the polyamides were prepared by solution casting and these polymer films show good optical transparencies with cut-off wavelengths of 337-367 nm and transparencies of 88%-90% at 550 nm. In addition, all the polymers were thermally stable over 400 °C and exhibited glass transition temperatures () higher than 300 °C. Unsymmetrically inserted trifluoromethyl groups on polyamides improves the solubility as well as the transparency of the polymers while maintaining good thermal properties. They also showed low refractive indices around 1.5333~1.5833 at 633 nm owing to the existence of low polarizable trifluoromethyl groups.
由含三氟甲基（CF）的不对称二胺单体4-(4'-氨基苯氧基)-3,5-双（三氟甲基）苯胺合成了可溶性且透明的全芳香族聚酰胺（PA）。该单体通过山崎-东缩聚法与几种二羧酸单体聚合。所有合成的聚酰胺均具有无定形形态，并且在室温下可溶于许多极性有机溶剂。通过溶液浇铸制备了聚酰胺的柔性透明薄膜，这些聚合物薄膜具有良好的光学透明度，截止波长为337 - 367 nm，在550 nm处的透明度为88% - 90%。此外，所有聚合物在400℃以上具有热稳定性，玻璃化转变温度（）高于300℃。聚酰胺上不对称插入的三氟甲基基团在保持良好热性能的同时提高了聚合物的溶解性和透明度。由于存在低极化率的三氟甲基基团，它们在633 nm处的折射率也较低，约为1.5333~1.5833 。
