Low Dielectric Polyetherimides Derived from Bis[4-(4-(4-aminophenoxy)-2-tert-butylphenoxy)phenyl] Sulfone and 4,4′-Bis[4-(4-aminophenoxy)-2-tert-butylphenoxy]perfluorobiphenyl

[Image: see text] Two diamines, bis[4-(4-(4-aminophenoxy)-2-tert-butylphenoxy)phenyl] sulfone (PSNH(2)) and 4,4′-bis[4-(4-aminophenoxy)-2-tert-butylphenoxy)perfluorobiphenyl (PFNH(2)), were prepared from 3-tert-butyl-4-hydroxyanisole using a four-step procedure, including two nucleophilic substitutions, demethylation, and catalytic reduction. On the basis of PSNH(2) and PFNH(2), two series of low dielectric polyetherimides (PEIs) were prepared. Both series of PEIs exhibit moderate-to-high thermal properties, including a glass transition temperature (T(g)) > 259 °C (depending on the rigidity of dianhydride), a 5 wt % decomposition temperature (T(d5%)) > 496 °C, and a coefficient of thermal expansion < 66 ppm/°C. Because of the hydrophobic tert-butyl phenylene oxide structure, both series of PEIs show excellent dielectric properties, with a dielectric constant as low as 2.4–2.7. The structure–property relationship of both series of PEIs is discussed in this work.