Preparation of functional silica-based colloidal composites by radiation-induced polymerization

LEANDRO MARTÍNEZ; MIRNA SÁNCHEZ; PAMELA KIKOT; MARIANO GRASSELLI

Jeju island

Simposio; 11th Meeting of the Ionizing Radiation and Polymers Symposium IRaP; 2014

Korean Society of Radiation Industry

Fumed silica (FSi) is one of the few nanomaterials used in large scale in the production of several industrial products. In addition, the very low toxicity of this nanosize particles became in an excellent raw material for develop novel applications in the field of downstream processing of bioproducts. In this work are prepared and characterized a colloidal composite based on fumed silica with protein adsorptive properties. Nanocomposite was prepared by radiation-induced polymerization of glycidyl methacrylate (GMA) without stirring. The gamma-ray irradiation of an aqueous solution of GMA, at low monomer concentration, with the presence of FSi nanoparticles (NP), reaches a monodisperse nanocomposite. The average diameter and size-distribution of water suspension of the colloidal NP were determined by DLS. The average diameters for the different preparation conditions change from 195 nm to 60 nm with an approximately 10% of standard error. Samples were also characterized by ATR FT-IR spectroscopy and TGA analysis. The increment of polymer ratio in the final NP composition yields higher NP diameter. However this correlation is not linear and it is approaching to a plateau when polymer mass become higher. Taking into account to the initial GMA/FSi ratio, mono-disperse nanoparticles from 60 to 195 nm were achieved contain approximately 99 to 55% of silica by mass. Sulfonic groups were further introduced in pGMA/FSi NP through reaction of sulfite onto the epoxy-pendant groups of pGMA. The negative surface change composition of the NPs was examined by zeta potential versus pH. Sulfonic NP allows reversible protein adsorption from a lysozyme solution up to 270 mg/g. This protein adsorptive property, in addition to a simple recovery method of NP by centrifugation and non-toxic preparation materials, becomes to this colloidal nanocomposite in an interesting adsorbent to be applied in the field of protein purification. This preparation method has several advantages such as it is a simple, one-pot protocol based on readily available starting materials; no addition of surfactant is necessary during the preparation and it is a non-stirring reaction. Also no surface pretreatment of the FS is required, and the reactivity of GMA can be used for a wide-range of NP functionalization.