Influence of ionic liquid on selective polycondensation of a new diamine-bisphenol: Synthesis and properties of polyamides and their composites with modified nanosilica

This work reports that imidazolium-based ionic liquids (ILs) are very efficient solvents and catalysts for the selective synthesis of novel high performance polyamides (PAs) from a new diamine-bisphenol. Direct polycondensation of the diamine-bisphenol was carried out with various dicarboxylic acids by using mixture of: (1) triphenylphosphite (TPP)/N-methylpyrolidone (NMP)/pyridine (Py)/LiCl; and (2) IL/TPP. The PAs were obtained in no more than 2.5 h at 110 °C, which is considerably shorter than the conventional direct polycondensation, with mass-average molar mass (Mw) up to 61,000 g mol−1, glass transition temperatures (Tg) up to 325 °C and 10% weight loss temperatures (T10%) up to 511 °C (in N2) and 456 °C (in air). Nanocomposites of these PAs with modified nanosilica (mNS) showed that strong chemical bonding between inorganic particles and the polymer matrix contributed to the enhanced thermal and mechanical properties. The photoluminescence intensity of the PAs increased and the spectra red shifted with increasing mNS content. The PAs and nanocomposites were tested for their extraction capability of metal ions such as Cr3+, Co2+, Zn2+, Pb2+, Cd2+, Hg2+ and Fe3+ from aqueous solutions either individually or in the mixture.