Recent progress on improving the mechanical, thermal and electrical conductivity properties of polyimide matrix composites from nanofillers perspective for technological applications

The adoption of polymer nanocomposites in the design/manufacturing of parts for engineering and technological applications showcases their outstanding properties. Among the polymer nanocomposites, polyimide (PI) nanocomposites have attracted much attention as a composite material capable of withstanding mechanical, thermal and electrical stresses, hence engineered for use in harsh environments. However, the nanocomposites are limited to the application area that demands conduction polymer and polymer composites due to the low electrical conductivity of PI. Although, there has been advancement in improving the mechanical, thermal and electrical properties of PI nanocomposites. Thus, the review focuses on recent progress on improving the mechanical, thermal and electrical conductivity properties of PI nanocomposites via the incorporation of carbon nanotubes (CNTs), graphene and graphene oxide (GO) fillers into the PI matrix. The review summarises the influence of CNTs, graphene and GO on the mechanical and conductivity properties of PI nanocomposites. The authors ended the review with advancement, challenges and recommendations for future improvement of PI reinforced conductive nanofillers composites. Therefore, the review study proffers an understanding of the improvement and selection of PI nanocomposites material for mechanical, thermal and electrical conductivity applications. Additionally, in the area of conductive polymer nanocomposites, this review will also pave way for future study.

Novel Polyimide/Copper-Nickel Ferrite Composites with Tunable Magnetic and Dielectric Properties

Heat-resistant magnetic polymer composites were prepared by incorporating cerium-doped copper-nickel ferrite particles, having the general formula Ni1-xCuxFe1.92Ce0.08O4 (x: 0.0, 0.3, 0.6, 1.0), into a polyimide matrix. The effects of particle type and concentration on the thermal, magnetic, and electrical properties of the resulting composites were investigated. The samples were characterized by FTIR, scanning electron microscopy, X-ray diffractometry, thermogravimetric analysis, differential scanning calorimetry, vibrating sample magnetometer, and broadband dielectric spectroscopy. The composites exhibited high thermal stability, having initial decomposition temperatures between 495 and 509 °C. Saturation magnetization (Ms), magnetic remanence (Mr), and coercivity (Hc) were found in range of 2.37–10.90 emu g−1, 0.45–2.84 emu g−1, and 32–244 Oe, respectively. The study of dielectric properties revealed dielectric constant values of 3.0–4.3 and low dielectric losses of 0.016–0.197 at room temperature and a frequency of 1 Hz.

“All Polyimide” Mixed Matrix Membranes for High Performance Gas Separation

To improve the interfacial compatibility of mixed matrix membranes (MMMs) for gas separation, microporous polyimide particle (AP) was designed, synthesized, and introduced into intrinsic microporous polyimide matrix (6FDA-Durene) to form “all polyimide” MMMs. The AP fillers showed the feature of thermal stability, similar density with polyimide matrix, high porosity, high fractional free volume, large microporous dimension, and interpenetrating network architecture. As expected, the excellent interfacial compatibility between 6FDA-Durene and AP without obvious agglomeration even at a high AP loading of 10 wt.% was observed. As a result, the CO2 permeability coefficient of MMM with AP loading as low as 5 wt.% reaches up to 1291.13 Barrer, which is 2.58 times that of the pristine 6FDA-Durene membrane without the significant sacrificing of ideal selectivity of CO2/CH4. The improvement of permeability properties is much better than that of the previously reported MMMs, where high filler content is required to achieve a high permeability increase but usually leads to significant agglomeration or phase separation of fillers. It is believed that the excellent interfacial compatibility between the PI fillers and the PI matrix induce the effective utilization of porosity and free volume of AP fillers during gas transport. Thus, a higher diffusion coefficient of MMMs has been observed than that of the pristine PI membrane. Furthermore, the rigid polyimide fillers also result in the excellent anti-plasticization ability for CO2. The MMMs with a 10 wt.% AP loading shows a CO2 plasticization pressure of 300 psi.

A review on recent advances on improving polyimide matrix nanocomposites for mechanical, thermal, and tribological applications: Challenges and recommendations for future improvement

In recent years, advancements on improving the mechanical and tribological properties of polyimide nanocomposites have remarkably increased, owing to the fact that polyimide nanocomposites exhibits lightweight, high strength, thermal stability as well as anti-wear and solvent resistance. The polyimide nanocomposites are described as material of polyimide matrix reinforced with certain volume or weight percent concentration of nanofillers. Researchers have demonstrated the importance of thermoplastic polyimide nanocomposites in mechanical, thermal, and tribological applications. However, the nanocomposites are reportedly facing interfacial adhesion issues and surface properties degradation, which have affected their mechanical, friction, and abrasive wear resistance for tribological applications. Although, much advancements on improving the mechanical, thermal, and wear resistance properties of polyimide nanocomposites has been reported. However, this review summarizes the effects of nanofillers, such as carbon nanotubes (CNTs), graphene (GN), graphene oxide (GO), boron nitride (BN), molybdenum disulfide (MoS2), silica (SiO2), titania (TiO2), alumina (Al2O3), carbon fibres (CF), aramid fibre (AF), glass fibre (GF), zinc dioxide (ZnO2), zirconium dioxide (ZrO2), silicon nitride (Si2N4), and carbon nitride (C3N4) on the mechanical, thermal, and wear properties of polyimide nanocomposites for tribological applications. The authors concluded the review study with advancement, challenges and suggestions for future improvement of polyimide nanocomposites as friction component material. Thus, the review offers an insight into the improvement and selection of polyimide nanocomposites material for mechanical, thermal, and tribological applications. More so, the review will also give away for further research.