Thermally highly stable polyhedral oligomeric silsesquioxane (POSS)-sulfur based hybrid inorganic/organic polymers: synthesis, characterization and removal of mercury ion

Abstract

Elemental sulfur was copolymerized with octavinyl polyhedral oligomeric silsesquioxane (OV-POSS) cages in diglyme solution via the inverse vulcanization method and characterized using NMR and FTIR spectroscopic techniques. The polysulfur copolymer called poly(sulfur-random-octavinyl polyhedral oligomeric silsesquioxane) (poly(S-r-OV-POSS)) was cured successfully sequentially at 170, 200 and 230 °C without changing the structure of the POSS cages in the polymer backbone. Highly crosslinked poly(S-r-OV-POSS) polymer cured at 200 and 230 °C exhibited high thermal stability at high temperatures; the loss of the samples was only 10% weight at 400 °C and 27% at 800 °C. Finally, the feasibility of poly(S-r-OV-POSS) as an adsorbent for the removal of Hg(II) ions, as an example of a toxic heavy metal, from an aqueous solution was investigated. Optimization of the pH of the solution and contact time was performed and almost all Hg(II) ions were collected from the aqueous solution at pH = 7 in 1 h (99% adsorption).