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 <i>E. coli</i>, <i>Pseudomonas aeruginosa</i>, <i>S. aureus</i>, and <i>Bacillus subtilis</i>. 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.