Smart synthesis of silver nanoparticles supported in porous polybenzoxazine nanocomposites via a main-chain type benzoxazine resin

In this article, novel silver nanoparticles immobilized on macroporous polybenzoxazine nanocomposites (Ag-poly(BA-ddm)^x_main) were prepared as catalysts for catalytic reduction reaction. For this purpose, a main-chain type benzoxazine was cured in dimethyl sulfoxide by thermally activated ring-opening polymerization at 180 °C for 2 days followed by the reduction of silver nitrate in homogeneous polybenzoxazine solution. The porous structure of the resin was confirmed by scanning electron microscope (SEM) analysis and N₂ adsorption/desorption studies. Besides, transmission electron microscopy images showed that spherical particles (around 3–10 nm in sized) are dispersed in Ag-poly(BA-ddm)^x_main network. The catalytic activity of the as-prepared nanocomposite has been investigated by photometrically monitoring the reduction of methylene blue by an excess of NaBH₄. The kinetic data of the reduction reaction was explained by the assumption of a pseudo-first-order reaction with regard to methylene blue (MB). As evidence by Ultraviolet (UV) spectral analysis, the Ag-poly(BA-ddm)^x_main catalyst possesses excellent catalytic reduction of MB, and no deactivation or poisoning of the catalyst was observed. The results demonstrate that porous polybenzoxazine supported silver nanoparticles can be applied as reusable catalysts with satisfied catalytic activity.