High-temperature hybrid phthalonitrile/amino-MMT nanocomposites: Synthesis, structure, properties

Abstract

Hybrid nanocomposites based on heterocyclic network, obtained from bisphenol A based phthalonitrile (BAPhN) with different (0.03-5.0 wt%) contents of reactive amino-montmorillonite (MMT) nanolayers, were synthesized and studied for the first time. Their structure, dynamics, thermal, relaxation and elastic properties were characterized using transmission electron microscopy (TEM), mid-infrared (mid-IR), far-infrared (far-IR) and energy dispersive X-ray (EDX) spectroscopies, differential scanning calorimetry (DSC), and by dynamic mechanical analysis (DMA) and thermogravimetry (TGA) measurements performed in both air and nitrogen mediums at temperatures from 20 to 600-900°C. Depending on nanofiller content, different extents of MMT stacks exfoliation, from single nanolayers to MMT stacks with tens nanolayers-thickness, are observed in the nanocomposites. The pronounced dynamic heterogeneity in the glass transition and the 'constrained dynamics' effects are shown. For the pristine matrix, T g (DMA) = 446°С varying from 460 to 570°С for the nanocomposites. After high-temperature treatment in N 2 medium, the relaxation spectrum and glass transition disappear, and constant dynamic modulus E′ ≈ 3 GPa at 20-600°С is registered. A satisfactory thermal stability of the nanocomposites, with retaining the sample integrity is observed at temperatures up to ~500°C in air and up to 900°C in N 2 medium.

Polymerization mechanism of 4-APN and a new catalyst for phthalonitrile resin polymerization

“…[7][8][9] This promoted the development of PN resin, 9,11 which has happened rapidly over the past 20 years. [12][13][14][15][16][17][18] Among these PN catalysts, the catalysts containing -NH 2 have the highest outstanding catalytic performance and have been widely used, [19][20][21][22][23][24] such as p-BAPS, 25 m-APB, 26 4-APN, 5 etc. (shown in Fig.…”