Synthesis, characterization and bioactivity of chalcone-based polybenzoxazine/copper oxide nanocomposites

In the current work, a chalcone-based benzoxazine monomer was synthesized by Mannich condensation reaction using octadecylamine, paraformaldehyde, and a hydroxylated chalcone in a co-solvent of toluene/ethanol. The resulting benzoxazine monomer was mixed with nanoparticles of copper oxide at different ratios to obtain polybenzoxazine/copper oxide nanocomposites. The structure of the benzoxazine monomer was verified using FTIR and ¹H NMR, while the structure of polybenzoxazine/copper oxide nanocomposites was investigated using FTIR and XRD. The morphology of the resultant composites was examined using SEM and TEM. The thermal properties of polybenzoxazine/copper oxide nanocomposites were studied using TGA. The resulting composites were tested for antibacterial activity against some bacteria such as E. coli, Pseudomonas aeruginosa, S. aureus, and Bacillus subtilis. Also, the cytotoxic activity of the resulting materials was tested against some human cells like Mammary gland breast cancer (MCF-7), hepatocellular carcinoma (HEPG-2), human prostate cancer (PC-3), and colorectal carcinoma colon cancer (HCT-116). The incorporation of nanoparticles of copper oxide into the polybenzoxazine matrix enhanced the thermal stability, increased the char yield, and improved the bioactivity of benzoxazines. The bio-efficiency of these materials increased as the ratio of copper oxide in the composites was increased.