Resumen

RODRIGUEZ-QUIROS, Henry Alberto  y  CASANOVA-YEPES, Herley Fernando. Effect of the functionalization of silica nanoparticles as a reinforcing agent on dental composite materials. Rev.fac.ing.univ. Antioquia [online]. 2015, n.75, pp.36-45. ISSN 0120-6230.  https://doi.org/10.17533/udea.redin.n75a05.

The present study evaluated the effect of silica nanoparticle aggregation state on the reflectance and crystallinity of dental composite materials. Two types of silica nanoparticles (ca. 10 nm): Aerosil 200^® non-funcionalized and Aerosil DT4^® funcionalized with 3-methacryloxypropyltrimethoxysilane. Nanoparticles were dispersed in a monomer mix composed by Urethane Dimethacrylate (UDMA) and Ethylene glycol Dimethacrylate (EGDMA) in a 80:20 mass ratio. The particle size of silica and their aggregation state were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), showing that the Aerosil DT4^® has dense aggregates with sizes higher than 1 µm; on the other hand the Aerosil 200^® showed a particle gel-like structure. The functionalization degree of the Aerosil DT4^® was determined by thermogravimetric analysis (TGA), obtaining a value of 7.57% w/w. The composite materials were evaluated by Differencial Scanning Calorimerty (DSC) to determine their crystallinity. The composite material reinforced by Aerosil DT4^® showed lower cristallinity than the system with Aerosil 200^® due to higher interaction of the polymeric matrix with the funcionalized surface of the Aerosil DT4^®. The effect of the aggregation state of silica nanoparticles on the optical properties of the composite material was determined by reflectance analysis. The Aerosil 200^® sample showed a lower degree of nanoparticle aggregation and higher reflectance than the system with Aerosil DT4^®. The functionalization of the Aerosil DT4^® induced nanoparticle aggregation diminishing the optical properties of the composite material.

Palabras clave : composite material; functionalization; silica; UDMA; EGDMA; particle size; dental materials.

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