Resumo

HERRERA-KAO, W.  e  AGUILAR-VEGA, M.. Effect of process additives on the properties of policarbonate nanocomposites with inorganic nanoparticles. Rev. Mex. Ing. Quím [online]. 2008, vol.7, n.2, pp.163-170. ISSN 1665-2738.

Bisphenol A Polycarbonate, PC and silica nanoparticles (Aerosil R-972) or Cloisite 30B nanocomposites were prepared by melt-blending. The silica nanoparticles were treated with 10 and 20 wt % of the stearic acid. Nanocomposites with 1, 5 and 7.5 wt % of filler were tested. The effect of stearic acid concentration on the dispersion of silica nanoparticles was investigated. Thermal properties were obtained by Differential Scanning Calorimetry and mechanical and dynamic mechanical properties were also determined. It was found that Tg decreased with increasing concentration of stearic acid treated silica or Cloisite 30B content due to plasticization of the PC matrix. A fact that is attributed to the presence of increasing concentrations of stearic acid or the tensoactive used in the nanoclay. On the other hand, it was found that the tensile modulus, E, and storage modulus, E', increased with increasing content of silica with additive or Cloisite 30B. This behavior was attributed to an increase in stiffness of the nanocomposite owing to nanoparticles concentration and an improved distribution in the PC matrix of silica treated with stearic acid. However, it was observed that the thermal stability of the nanocomposites, decreases as the concentration of treated silica with stearic acid or Cloisite 30B increases in the composite.

Palavras-chave : polycarbonate; nanoparticles; mechanical properties; nanocomposites.

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