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Copper films with a thickness of 220 nm were deposited onto polyester fabrics by magnetron sputtering technology. To improve the stability of copper films in synthetic perspiration, the Cu-coated fabric was treated by a solution of Benzotriazole (BTA). Finishing agents with 0.1, 0.5, 1, 5, 10 g/L concentrations were applied on Cu-coated fabrics by a method of impregnation. The surface morphologies were observed by scanning electron microscopy (SEM). The electromagnetic interference shielding effectiveness (EMI-SE) and the electrical conductivity were measured to characterize the degree of damage to the copper film, respectively. In addition, the ultraviolet (UV) absorption of the fabrics treated with differ rent concentrations of BTA was investigated. The results show that the protective ability of BTA on copper film in synthetic perspiration improved with the increase of its concentration; and the copper film treated with the BTA concentration of 1 g/L presented good stability, which the sheet resistance value was 1.15 Ω/sq, and the average of EMI-SE value was 35 dB. However, when the BTA concentration is higher than 1 g/L, both the EMI-SE and conductivity were reduced. The BTA treatment improved the stability of Cu-coated fabrics in synthetic perspiration, which can help enlarge the application area of Cu-coated fabrics.

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.

To develop high performance of polymer-based composites, the dispersion state and interfacial interaction of nano-fillers are two key issues to be considered. Herein, we report the surface decoration of basalt fibers (BF) with nano-sized barium titanate (BT) particles and their dielectric application in poly(ether sulfone)-based composite laminates (PBCLs) was investigated in detail. Firstly, the nano-sized BT particles uniformly deposited along the BF surface through a simple and effective solvothermal method, as confirmed by SEM and XRD measurement. Then, novel ternary dielectric polymer-based composite laminates, consisting of BT particles decorated BF and poly(ether sulfone) (BT–BF/PES), were fabricated by hot-pressing method. Compared to raw BF filled PBCLs, the SEM images of BT–BF fibers reinforced PBCLs showed that all the BT–BF fibers strongly adhere to the PES matrix, and obscure fiber/PES interfaces are present without visible boundaries, indicating a improved interfacial interactions in this case. Thus, the mechanical, thermal and dielectric properties of the resultant PBCLs were characterized and results indicated that the BF and BT particles show enhanced synergistic effects. Following this strategy, the flexural strength and dielectric constant of BT–BF/PES blend with 40 wt% of BT were increased by 28 and 350%, respectively, in comparison with those of BF/PES composite laminates.

A novel soluble poly(aryl ether ketone) (PAEK) terminated with 4-nitrophthalonitrile was designed and synthesized, which was used to solve the problem of difficult solution processing. Then, a series of cross-linked PAEK films with different thermal treatment temperatures were fabricated by using 4,4-bis(3,4-dicyanophenoxy)biphenyl (BPH) as a novel cross-linking agent, improving the glass transition temperature (Tg) of the traditional PAEK. Then, the fourier transform infrared (FT-IR) spectrum, X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), dynamic mechanical analysis (DMA), mechanical testing machine and LCR meter were used to investigate the microstructure, thermal, mechanical and dielectric properties of PAEK films, respectively. The results indicated that the increase in heat-treatment time and temperature are beneficial for the improvement of the value of Tg and T5%, and the excellent thermal stability and mechanical properties of PAEK films are demonstrated. Compared to PAEK-1 film, the Tg and T5% both increased by 63 °C for PAEK-4 film. Significantly, the tensile strength of PAEK-3 film (42 MPa) reaches the highest value in comparison with other samples. In addition, the dielectric constants (e) and loss tangent (tan δ) of PAEK-4 film is as low as 3.67 and 0.001 at 1 kHz, respectively. More importantly, the dielectric properties are found to be relatively stable to near the Tg value, which can be widely used for applications in dielectric energy storage at high temperatures.

In this work, a series of novel organosoluble copoly(arylene ether nitriles) containing thioether moiety (PENS) were synthesized via nucleophilic aromatic substitution polymerization of 2,6-dichlorobenzonitrile with bisphenol A and sodium sulfide nonahydrate, using N-Methyl-2-Pyrrolidone as solvent in the presence of anhydrous potassium carbonate. The chemical structures of PENS were characterized by FTIR and 1H NMR. The derived copolymers showed high glass transition temperatures in the range of 167–178 °C and excellent thermal stability with the 5% weight loss temperatures ranging from 465 °C to 503 °C. Meanwhile, all of the PENS were amorphous and can be readily cast into transparent films with a tensile strength exceeding 77 MPa and a breaking elongation over 4.8%.In addition, the dielectric constant of all the PENS copolymers showed weak frequency dependence, the dielectric loss showed slight decrease with increasing frequency over the range of 100 Hz to 200 kHz. Therefore, this kind of organosoluble copoly(arylene ether nitriles) containing thioether moiety could be a good candidate as matrix resins for high-performance polymeric materials.

In this report, flexible cross-linked polyarylene ether nitrile/functionalized barium titanate(CPEN/F-BaTiO3) dielectrics films with high permittivitywere prepared and characterized. The effects of both the F-BaTiO3 and matrix curing on the mechanical, thermal and dielectric properties of the CPEN/F-BaTiO3 dielectric films were investigated in detail. Compared to pristine BaTiO3, the surface modified BaTiO3 particles effectively improved their dispersibility and interfacial adhesion in the polymer matrix. Moreover, the introduction of F-BaTiO3 particles enhanced dielectric properties of the composites, with a relatively high permittivity of 15.2 and a quite low loss tangent of 0.022 (1 kHz) when particle contents of 40 wt % were utilized. In addition, the cyano (–CN) groups of functional layer also can serve as potential sites for cross-linking with polyarylene ether nitrile terminated phthalonitrile (PEN-Ph) matrix and make it transform from thermoplastic to thermosetting. Comparing with the pure PEN-ph film, the latter results indicated that the formation of cross-linked network in the polymer-based system resulted in increased tensile strength by ~67%, improved glass transition temperature (Tg) by ~190 °C. More importantly, the CPEN/F-BaTiO3 composite films filled with 30 wt % F-BaTiO3 particles showed greater energy density by nearly 190% when compared to pure CPEN film. These findings enable broader applications of PEN-based composites in high-performance electronics and energy storage devices materials used at high temperature.