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In this work, ultralow dielectric constant (ultralow-k) polysulfone (PSF) composites were prepared by adding hollow glass beads (HGB) modified with 1,3-divinyltetramethyldisiloxane (DVTM). The results indicated that the surface modification of HGB (m-HGB) effectively enhanced the interfacial compatibility between the inorganic fillers and PSF matrix. DSC and TGA measurements of the composite films were performed under a nitrogen atmosphere, and the results showed that the composite films possess high glass transition temperatures varying from 187 °C to 190 °C, and are thermally stable␣up to 445 °C. The mechanical properties of composite films with modified HGB fillers show a certain drop, but the values were still higher than 32 MPa. Furthermore, the obtained composite films show low dielectric constant, low dielectric loss, good permittivity-frequency stability and dielectric-temperature stability under 190 °C. Therefore, we shown an effective path to prepare composites with ultralow dielectric constant for use in high temperature resistant ultra large scale integration (ULSI) flexible insulation substrate field. [ABSTRACT FROM AUTHOR]

Polyarylene ether nitrile (PEN) random copolymers were prepared from 6AF, BHPF, and 2, 6-dichlorobenzonitrile according to the nucleophilic aromatic substitution polymerization. The chemical structure of PEN random copolymers was characterized by the FT-IR and 1H-NMR spectrum, respectively. The thermal properties of the PEN random copolymers were investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The resulting PEN copolymers have excellent thermal stability with high glass transition temperature (Tg) ranging from 187℃ to 271℃ and the 5% weight loss temperature (T5%) of PEN copolymers greater than 490℃ in nitrogen atmospheres. Meanwhile, the PEN films have excellent mechanical property, the tensile strength ranges from 55 to 95 MPa. Moreover, the dielectric properties of the PEN random copolymers were investigated by dielectric tests. The dielectric constants (k) and loss tangent (tan δ) of PEN (PEN-6-AF/BHPF100) film is only 2.3 and 0.03 at 1 kHz, respectively. More importantly, the dielectric properties were found to be relatively stable until the Tg, which can be attributed to the existence of BHPF units in the molecular backbone. [ABSTRACT FROM AUTHOR]

In this work, a series of fluorine‐functionalized polysulfone (F‐PSU) copolymers with intrinsic low dielectric constants (low ε) are reported, which are derived from the polycondensation reaction of 4,4′‐dichlorophenyl sulfone with bisphenol A and bisphenol F (BPF) compounds. The resulting F‐PSU copolymers show high glass transition temperatures (Tg) varying from 187 to 201 °C and are thermally stable up to 500 °C under an N2 atmosphere. The introduction of BPF units into the PSU copolymers imparts enhanced hydrophobic properties to the F‐PSU films with increased water contact angle values from 66.2° to 93.7°. Moreover, the dielectric constant and dielectric loss of the F‐PSU (sample V) film are as low as 2.2 and 0.003 at 1 kHz, respectively. Interestingly, the dielectric properties are relatively stable to near the glass transition temperature, which is because of the existence of BPF structures in the molecular backbone. Furthermore, the F‐PSU copolymers are soluble in common solvents and can be readily fabricated into flexible transparent films by the spin casting method. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A series of novel cross-linkable PSF-6AF/DBA copolymers with different structure were successfully synthesized via nucleophilic aromatic substitution stepwise polymerization of 4,4′-dichlorodiphenyl sulfone (DCS) with hexafluorobisphenol A (6AF) and 4,4′-(propane-2,2-diyl)bis(2-allylphenol) (DBA) monomer. The 6AF and DBA moieties with a large number of pendant groups had been successfully introduced into the PSF polymer chain. Then, the PSF-6AF/DBA films were fabricated by casting the PSF-6AF/DBA/DMF solutions with the concentration of 10% on the clean glass plates, followed by heat-treating all the films at 300 °C for 4 h. The effects of both the component and cross-linking on the thermal, mechanical and dielectric properties of the obtained films were investigated in detail. Compared to PSF-6AF/DBA films, the cross-linked PSF-6AF/DBA (CS-PSF-6AF/DBA) films show high glass transition temperature (Tg= 184–197 °C) and outstanding mechanical strength (64–77 MPa). More importantly, all CS-PSF-6AF/DBA films display stable dielectric properties in the temperature range of 20–200 °C. The permittivity of CS-PSE-6AF/DBA film at 1 kHz is as low as 2.1, while the dielectric loss is only 0.007. [ABSTRACT FROM AUTHOR]

In this study, a series of fluorinated polyethersulfone (PES-6AF) copolymers with intrinsic low-dielectric-constants are prepared by the introduction of fluorine-containing group, which are derived from the polycondensation reaction of 4,4′-dichlorophenyl sulfone (DCS), bisphenol S (BPS) and six fluorine hexafluorobisphenolA (6AF) compounds by nucleophilic aromatic substitution. Different proportions of PES-6AF copolymers show high glass transition temperatures (Tg) ranging from 206 °C to 230 °C, and the thermal decomposition temperatures of PES-6AF copolymers are up to 500 °C under N2 atmospheres. The PES-6AF copolymers display outstanding tensile strength (62–69 MPa). Added different proportions of 6AF into the PES-6AF copolymers could improve dielectric property and decrease dielectric constant (k) from 3.6 to 2.5 at 1 kHz. In addition, the dielectric properties were found to be relatively stable until the Tg, it is because that the 6AF units were existed in the molecular backbone. Furthermore, the PES-6AF copolymers were soluble in many common solvents and could be made the molten films using DMF as solvent. [ABSTRACT FROM AUTHOR]