Novel cardo‐type heat‐resistant polyimides bearing 9H‐xanthene and polymer‐based nanocomposite consisting of NH₂‐terminated TiO₂: Synthetic strategies, extraction of methylene blue dye, and biological activities

Abstract

In the present study, a series of cardo‐type novel polyimides (PI)s containing xanthene groups was synthesized. All the polymers were amorphous in nature with inherent viscosities in the range of 0.72–0.91 dl/g. Study of thermal behavior showed that PIs have excellent thermal stability with 10% weight loss at temperatures (Td10%) between 426 and 528 °C, glass transition‐related temperatures (Tg) in the range of 292–305 °C, and weight residual at 700 °C ranged from 55% to 68% under N2 atmosphere. Xanthene and fluorene presence, progressed the PIs solubility and also induced good biological activities. The in vitro anticancer activity of the 6FD‐derived PI against the A431 (epidermoid carcinoma) cells showed an IC50 value of 29.3 μM. In the next part of the work, a polymer‐based composite (PI‐B/m‐TiO2@HBP) was prepared by inscribing 20 wt% of hyperbranched polyamide‐grafted TiO2 nanoparticles into BTDA‐derived PI‐B matrix, and compared with the unfilled PI, its photoluminescence intensity and thermal stability properties were increased. The PI‐B and nanocomposite exhibited good antibacterial activity against six bacterial strains. In the following, study of methylene blue (MB) dye adsorption from aqueous solution by the obtained PIs and PI‐B/HBP@TiO2 was carried out and removal efficiency values were found above 80.62%.