Study properties of nanocomposites prepared with new polyimides and reactive nanosilica by epoxide functionalization

In this article, new types of organosoluble polyimides, poly(carbazole‐quinoxaline‐imide)s (PCQI), were synthesized and used in preparation of nanocomposites with modified nanosilica (mNS). The synthesized polyimides bearing different solubilizing functional moieties were casted into thin films at room temperature. SiO₂ nanoparticles were surface modified with γ‐glycidoxypropyltriethoxysilane (GPTES) to obtain mNS containing epoxide functional groups. The PCQI/mNS nanocomposites were prepared via cure reaction of epoxide groups and polymer functional units. The PCQIs and nanocomposites films were tested for different properties including thermal using TGA and DMTA, mechanical, thermomechanical, photophysical, solubility, water uptake, and metal ions adsorption. The strong chemical bonding between mNS particles and polymer matrix reduced solubility of nanocomposite and enhanced thermal stability in term of 10% weight loss temperature (T_10%, from 509°C to 582°C) and tensile strength (from 110 MPa to 155 MPa). These polyimides and nanocomposites were also efficient chelating agents for removal of metal ions such as , Cr³⁺, Pb²⁺, Cd²⁺, and Hg²⁺ from aqueous solutions either individually or in the mixture and at different pH values. POLYM. COMPOS. 36:545–555, 2015. © 2014 Society of Plastics Engineers