The effects of chemical structure on the dielectric properties of polyetherimide and nanocomposites

Abstract

Low dielectric constant polyetherimides have been synthesized by incorporating a bisphenol A dianhydride, BPADA, and 2,7-bis(4-aminophenoxy) naphthalene (BAPN), a phenylene ether diamine. The flexible ether and larger planar naphthalene structure of BAPN led to more spacing between polymer molecules, resulting in less efficient chain packing and an increase in the free volume, thus decreasing the dielectric constant. New PEI/silica hybrid nanocomposites were prepared from this novel polyetherimide via sol-gel process. The dielectric constants were further decreased with the incorporation of silica. These synthesized PEI and nanocomposites have high thermal stability and good mechanical properties.

Dielectric and gas transport properties of the films of thermally stable poly(arylene ether ketone)s containing content‐tunable benzimidazole moiety

“…No strongly polar groups or substituents contained in polymers might be related to the considerably stable dielectric characteristics . For PAEK‐co‐x%BI, there are both the polar carboxyl and imidazole groups in the main chains, therefore, effects of polar moiety on dielectric constants should be considered.…”

Polymer/Silica Nanocomposites: Preparation, Characterization, Properties, and Applications

“…There are many different synthetic techniques used in the sol−gel process to generate polymer/silica hybrid materials, two approaches are normally utilized, as indicated in Scheme : (i) In situ formation of an inorganic network in the presence of a preformed organic polymer. – To obtain optically transparent materials, conditions need to be identified under which phase separation will not occur during both the gel forming and the drying processes. Introduction of covalent bonds between the inorganic and organic phases is common to reduce phase separation.…”

“…In order to introduce covalent bonds between two phases to decrease the extent of phase separation or to increase compatibility of the polymer/silica nanocomposites, coupling agents are widely used in the sol−gel process. Addition of the coupling agents can be accomplished by several paths: (i) copolymerization with the monomer(s) to obtain functionalized polymer; ,– (ii) reaction with the preformed polymer to modify it; – ,– (iii) addition to the silica precursor to modify it; ,– (iv) addition to the mixture of polymer and silica precursor. – ,– The most popular method is the second path. When polycondensation takes place between trialkoxysilyl groups on the polymer and TEOS, covalent bonds between two phases can be formed …”

Study on highly thermostable low‐k polymer films based on fluorene‐containing polyetherimides

“…The relatively low values are mainly due to presence of voluminous fluorene units in the molecular structure, which reduce the density of polar groups and, thus, the polarizability. [ 53,54 ] The introduction of isopropylidene group in the chemical composition of 3b increased the free volume and thus decreased the dielectric constant at values of 2.18–2.20 in the same frequency domain. Furthermore, the decrease of dielectric constant for 3c in the range of 1.96–1.98 may be associated with CF 3 groups.…”