Efecto del agente funcionalizante en las propiedades de nanocompuestos de polipropileno

JULIE MERCHAN SANDOVAL; MARCELO DANIEL FAILLA; LIDIA MARíA QUINZANI

Concepción

Congreso; 15 Congreso Internacional de Metalurgia y Materiales Argentino-Chileno (SAM-CONAMET'15); 2015

Sociedad Chilena de Materiales

in-situ functionalization ofPolypropylene (PP) during melt mixing with organophilic montmorillonite (o-MMT)to obtain nanocomposites is explored in this work. Thus, a slight hydrophiliccharacteristic is given to the polymer in order to be more compatible withclay. Two functionalizing agents are used, n-butyl acrylate (BA) and maleicanhydride (AM) and an organic peroxide as initiator of the reaction. Thismethodology simultaneously permits the generation of the compatibilizing agentand the dispersion and delamination of the clay. Rheological properties andpermeability are compared in this study for different concentrations of clay, 1wt. % of functionalizing agent and 750 ppm of peroxide. The used mixing methodis a sequential addition in a thermoplastic laboratory mixer of PP (untilmelting), followed by peroxide and functionalizing agent (mixing time: 20 min)and the final incorporation of the clay (another 20 min of mixing). Thissequence is found as optimal in previous studies.The lineal viscoelastic behavior of theanalyzed materials shows that the modification with n-butyl acrylate produces ahigher variation in materials respect to PP; achieving a quasi-solid behaviorin the composite with 10 wt. % of clay and BA. This suggests a higher degree ofexfoliation, which can be determined by analyzing the phase structure byelectron microscopy.As regard to the results of oxygen permeability,which are evaluated in films of thickness of about 150 ìm, a reduction inpermeability is attained for all prepared nanocomposites compared to PP.Reaching a reduction of ~ 25 % , with the addition of 5 % clay andfunctionalization with BA