Synthesis and properties of soluble polyimides based on isomeric ditrifluoromethyl substituted 1,4-bis(4-aminophenoxy)benzene

Synthesis and properties of new pyridine-bridged poly(ether-imide)s based on 4-(4-trifluoromethylphenyl)-2,6-bis[4-(4-aminophenoxy)phenyl]pyridine

“…This could be interpreted that the presence of hexafluoropropane might inhibit the free rotation of the polymer chain. According to the T g values of polyimides PIs, FPIs, and 6FPIs in Table 3, FPIs exhibited higher glass transition temperatures than PIs without -CF 3 , which might result from enhancement of large pendent trifluoromethylphenyl group to the rigidity of polymer chain, while 6FPIs exhibited the lowest T g values, which might because the introduction of the bulky -CF 3 side groups in the polymer backbone decreased the intermolecular interactions, thus leading to a decreased T g value [30]. That is to say that -CF 3 groups in the pendent phenyl groups in polyimide backbone showed positive effects on its thermal resistance while -CF 3 groups in the meta-positions of nitrogen showed negative effects on its thermal resistance in this case, which might be explained that the former enhanced the rigidity of polymer chain by inhibiting its free rotation while the later decreased the intermolecular interactions.…”

Gas transport properties of fluorinated poly(ether imide) membranes containing indan moiety in the main chain

“…Polyimides are the most outstanding classes of high-performance polymers, exhibit a number of outstanding properties such as excellent thermal and thermo-oxidative stability, solvent resistance, fire retardant, mechanical and electrical properties [11,12]. Polyimides are also an important class of polymers for membrane based gas separation.…”

Novel Non‐Coplanar and Tertbutyl‐Substituted Polyimides: Solubility, Optical, Thermal and Dielectric Properties

“…Therefore, the introduction of tertbutyl into the ortho position of the imide nitrogen hindered the rotation of the two aromatic rings around the C-N bonds, which increased the chain rigidity and T g of polymer. [27][28][29] Moreover, the presence of non-coplanar 4-tertbutylphenyl moieties on the polymer backone also improved the steric hindrance, leading to relatively higher rigidity of the polymer molecular chain. The PI-a exhibited the hightest T g value, which may be due to the rigidity of wholly aromatic dianhydride PMDA units.…”