Microwave‐assisted synthesis of nanocomposites from polyimides chemically cross‐linked with functionalized carbon nanotubes for aerospace applications

Abstract

Polymer‐carbon nanotube nanocomposites are extensively investigated for microelectronics and aerospace applications. In this study, novel polyimide/f‐MWCNT nanocomposites made from 2,4‐bis(4‐aminophenylamido)‐6‐chloroquinazoline, pyromellitic dianhydride and functionalized‐Multi Walled Carbon Nanotubes (f‐MWCNT) by an efficient microwave assisted method were investigated. The structure of the prepared diamine monomer was confirmed by FT‐IR, 1H‐NMR, and 13C‐NMR spectral techniques. The prepared nanocomposites (Tg values from 338°C to 375°C) show improved thermal property as indicated by differential scanning calorimetry and thermogravimetric analysis. Polyimide/f‐MWCNT nanocomposites were found to have higher dielectric constant, and the limiting oxygen index values of prepared nanocomposites are in the range of 29.5 to 35.5, indicating a high flame retardancy. Additionally, the morphological studies were conducted by X‐ray diffraction and scanning electron microscopy. Overall, it is observed that chemically connected polyimide‐functionalized carbon nanotube nanocomposites could be used for aerospace and microelectronics applications that require high Tg, dielectric constant and high flame retardancy.

Kinetic Features of Synthesis of Epoxy Nanocomposites

“…In short, it can be formulated as follows: structural nanocomposites, which are reinforcement structures based on carbon or glass fibers embedded in a polymer matrix modified with nanofillers, are the most important application of nanocomposites in the aerospace field [137], laminates, and sandwich structures. In addition, they can be used as anti-lightning [138], anti-radar [139] protection devices, flame retardant, and heat-resistant paints [140], ameliorating anti-corrosion performances [141].…”

New High-Performance Materials: Bio-Based, Eco-Friendly Polyimides

“…The main advantages of using microwaves in the synthesis of PIs are the rapid completion of polycondensation, high purity of final products, uniform temperature rise, and overall greener energy balance. Some small drawbacks refer to the less accessible upscale and the need to re-dissolve the final product to prepare PI films or membranes [115,116].…”

“…The reaction can be easily extended to a wide range of building blocks (common monomers' salts included [122,123]) and even to the direct production of various composites [114,116,124]. The viscosity value of the final products usually depends on the solubility of the final compound in the reaction medium.…”

Preparation of polyimide films via microwave-assisted thermal imidization

“…The nanocomposites synthesized by microwave-assisted heating exhibited a higher glass transition temperature (270 C) than those synthesized by conventional heating (241 C), indicating that microwave induced synchronous heating and achieved fast ensemble reaction. 23,24 According to previous reports, the mechanism of energy transfer in microwave heating occurs by electric dipolar coupling of the radiation to permanent dipole moments in the polymer, rather than by thermal conductivity as in conventional processing, so that the energy can be absorbed by polymer chains more uniformly and rapidly. 11,25 Meanwhile, microwave radiation may help to eliminate small molecules such as water in the polymerization and thus the equilibrium reactions shis to higher yield.…”