Synthesis and characterization of hyperbranched poly(ether sulfone)imides and MWCNTs‐COOH/NH₂ Nanocomposites

Abstract

A new triamine 1,3,5‐tris{4′‐[4″‐(4″′‐aminophenoxy) phenylsulfonyl]phenoxy} benzene (TAPPSPB) was synthesized and successfully polymerized into hyperbranched polyimides (HBPIs) with commercially available dianhydrides BTDA and PMDA by A2+B3 method. HBPI‐PMDA‐AMT2/MWCNT nanocomposites were prepared by the reaction of TAPPSPB with PMDA and amino functionalized MWCNT by the conventional two step method by varying the percentage of MWCNT (1, 3, 5, and 7 wt%).The structure of the amine and the resulting hyperbranched polyimides were characterized by FT‐IR, 1H, and 13C‐NMR analysis. The Tg and T5% temperature of the HBPIs and nanocomposites were in the range of 229‐266°C and 430‐493°C, respectively. The results from DSC and TGA show that the Tg and the thermal stability of the HBPI‐PMDA‐AMT2/MWCNT nanocomposites are higher than that of pristine HBPIs. The dielectric constant (in the range of 3.05–8.54 at 1 MHz) and dielectric loss (in the range of and 0.64–0.87 at 1 MHz) increased with an increase of MWCNTs‐COOH/NH2. SEM studies revealed that the MWCNT are evenly dispersed throughout the polymer matrix in the nanocomposites. X‐ray diffraction studies shows that the synthesized HBPIs and nanocomposites are amorphous in nature. POLYM. COMPOS., 40:600–614, 2019. © 2018 Society of Plastics Engineers

The effects of long and bulky aromatic pendent groups with flexible linkages on the thermal, mechanical and electrical properties of the polyimides and their nanocomposites with functionalized silica

“… 62 The LOI values of polymer should be above the threshold value of 26 which render them self-extinguishing, a valuable property for many applications where high flame resistance are required. 63 The LOI values of polyimide and nanocomposites are between 27 and 47 indicating high flame resistance with good self-extinguishing property. Here, the silica nano particles enhance the flame retardancy of polyimides.…”