IN SITU POLYMERIZATION FOR THE PREPARATION OF POLYETHYLENE/SILICA-SILVER NANOCOMPOSITES WITH ANTIMICROBIAL PROPERTIES

M. MILANI; H. E. ROMEO; G. B. GALLAND; R. KALIKOSKI; I. BELMONTE; I. E. DELL'ERBA; G. PAVOSKI; L. CAPELETTI; J.DOS SANTOS

Gramado

Conferencia; Brazilian Conference on Composite Materials; 2016

Polymer nanocomposites is one of the areas of the nanotechnology that has aroused mostinterest. In recent decades much research has been carried out using different polymer matrices and nanofillers (graphite, silver, gold, clay, silica, etc.). Metallic silver and silver based compounds have been investigated as antimicrobial agents. Polyethylene is commonly used in the medical field among others due to its characteristics of low price, chemical inertness and easy processing. The main objective of this work was to obtain nanocomposites with antifungal action with a good distribution of the Ag nanoparticles in the polymer matrix. The Ag nanoparticles were encapsulated with 3-aminopropyltrimetoxysilane (APTMS), applying different proportions of APTMS/Ag (2, 4 and 8).SEM images show that increasing ratios of APTMS/Ag resulted in the formation of smaller Agnanoparticles (55 nm, 23 nm and 13 nm, respectively), after acidic and basic sol-gel synthesis byreaction of Si-OCH3 from the Ag nanoparticles with the Si-OH of a commercial silica. SAXS analyses also confirmed the presence of smaller Ag nanoparticles, with increasing APTMS/Ag ratios.Antifungal testing of SiAg nanoparticles showed activity for all of the materials. The nanocomposites were synthesized by in situ polymerization of ethylene with both non-supported and supported metallocene catalysts. The yields of the polymerizations were high, being the non-supported catalyst more productive than the supported one. Polyethylene (PE)/SiAg nanocomposites with 1.0 to 2.4 wt.-% of SiAg were obtained. TGA showed an improvement in thermal stability for the nanocomposites, showing an increase of the initial degradation temperature of 14°C. The crystallization temperature increased 1-2 °C and the melting temperature 1-4 °C. SEM images show morphological differences between the nanocomposites prepared by non-supported and supported systems. The nanocomposites showed also antifungal activity.