Synthesis of poly(amide-imide)s containing two trifluoromethyl and biphenyl groups

Abstract

Among the high temperature polymers, poly(amide-imide)s have been emerging as one of promising materials due to high thermal stability and mechanical properties with balanced processability. Also, several properties such as thermal stability, optical property and thermo-dimensional stability could be controlled by modifying its structures, in a stage of monomer design. In this study, we synthesized new diamine monomers containing trifluoromethyl and biphenyl groups and diacid monomer containing two trifluoromethyl groups symmetrically. Using these synthesized monomers, PAIs were prepared by polyamidation and converted to film form by solution casting, The resulting PAIs having rigid p-phenylene groups were exhibited poor solubility. When the PAIs have aliphatic part in their backbone, yellow color of the PAI films were diminished. The more structure of PAIs was rigid, the higher thermal stability was shown. Also, PAIs containing rigid-rod structures were exhibited relatively low CTE.