Enhanced Interfacial and Dielectric Performance for Polyetherimide Nanocomposites through Tailoring Shell Polarities

Abstract

Polyimide (PI) and its derivative polyetherimide (PEI) have been widely investigated as promising candidates for dielectric energy storage due to their excellent intrinsic features. However, most of the current research for PI- or PEI-based dielectric nanocomposites only focuses on a certain polar group contained in a dianhydride monomer, while there are very few studies on exploring the effect of a series of polar groups derived from various dianhydride monomers on the dielectric properties of nanocomposites. To fill this gap, we herein fabricated and investigated a series of novel hyperbranched polyimides grafted on barium titanate nanoparticles (HBPI@BT) using different dianhydride monomers and their nanocomposites with the PEI matrix. The results showed that sophisticated hyperbranched structures effectively alleviated the incompatibility between fillers and the matrix, thus significantly improving the bonding energy of nanocomposites, especially for HBPI-S@BT/PEI (797.7 kJ/mol). The U d of HBPI-S@BT/PEI reached 8.38 J/cm3, which is 3.3 times higher than that of pure PEI. The HBPI-F@BT/PEI nanocomposites achieved high breakdown strength (∼500 MV/m) and low dielectric loss (0.008) simultaneously. The dielectric constants of HBPI@BT/PEI nanocomposites remained at a stable level from 25 to 150 °C. This work provides us promising hyperbranched structured materials for potentially advanced dielectric applications such as field effect transistors.

Scalable co-cured polyimide/poly(p-phenylene benzobisoxazole) all-organic composites enabling improved energy storage density, low leakage current and long-term cycling stability

“…On the other hand, the more detailed information of energy band structure, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is further obtained by conducting density functional theory (DFT) calculations. 27,37,38 It is commonly accepted that the valence band is below the HOMO level while the conduction band is above the LUMO level. According to the HOMO levels and LUMO levels, the band gap can therefore be calculated.…”

“…Once the temperature approaches T g , the BOPP polymers will lose their dimensional and dielectric stability, thus seriously displaying low dielectric constant and high dielectric loss. 23 To circumvent these problems, high temperature resistant polymers such as polyimide (PI), 17,24–26 polyetherimide (PEI) 27,28 and poly( p -phenylene benzobisoxazole) (PBO) 29–32 have been intensively exploited due to their superior thermal stability. In particular, PBO with much less water absorption and low dielectric loss characteristics is becoming a promising matrix for high-temperature dielectric materials.…”

Core@Double–Shell Engineering of Zn Particles toward Elevated Dielectric Properties: Multiple Polarization Mechanisms in Zn@Znch@PS/PVDF Composites

“…Furthermore, the double-shell structured fillers fabricated in this work efficiently realizes the possibility of high 𝜖′ and low loss in Zn-3/PVDF, facilitating the IP and enhancing both interparticle polarization and intraparticle polarization of composites as compared to the neat Zn/PVDF investigated previously. [26,[37][38][39][40][41][42][43] Thus, by carefully controlling the shell thickness and choosing an appropriate coating ratio, the dielectric properties of a composite can be optimized as a result, enabling the achievement of the best dielectric performances.…”

Preparation of fluorinated polyimides with low dielectric constants and low dielectric losses by combining ester groups and triphenyl pyridine structures

“…From eqn (1), the molar polarizability ( P m ) and molar volume ( V m ) are the two main factors affecting the D k of a material. Based on this theory, many ways of reducing D k can be deduced, such as (1) introducing unstable structures in the polymer chain to produce porosity or doping low- D k fillers 8,9 or (2) introducing low-polarity groups 7,10,11 and large-volume structural units. 12…”