Development of epoxy/ phosphonium modified bentonite nanocomposites

ROMINA OLLIER; CAREN ROSALES; ELISABETH PENOFF; MATIAS LANFRANCONI; VERA ALVAREZ

Puerto Iguazú

Congreso; 13º Congreso Binacional de Metalurgia y Materiales (SAM-CONAMET 2013); 2013

Epoxy-based thermosetting polymer resins are widely used in several industrial applications because of their outstanding characteristics such as light weight, chemical resistance and elevated thermal and mechanical properties. However, epoxies are brittle and they tend to absorb significant amounts of moisture when exposed to humid conditions, which has detrimental effects on the physical properties of epoxy and can therefore greatly compromise the performance of an epoxy based component. To improve this, they may be reinforced with fillers. Clays can effectively enhance thermal, mechanical and barrier properties of epoxy resins even at low loadings. It is well known that the enhancement in the nanocomposite properties strongly depends on the level of clay dispersion in the polymer matrix. Two different morphological structures are mainly achievable: nanocomposites with either intercalated or exfoliated clay mineral. Clays can be organically modified through ion exchange reactions to facilitate the intercalation of polymers into the interlayer galleries and therefore facilitate the formation of an exfoliated structure. Many researchers have been working on nanocomposites based on epoxy/ammonium modified clays; however, there are few publications regarding the optimization of clay modification with phosphonium and the subsequent preparation of epoxy based nanocomposites. In this work, epoxy-amine based nanocomposites with different loadings (1 and 3 wt. %) of an organically modified bentonite were prepared and their properties were investigated. First, the neat bentonite was exchanged with an alkylphosphonium salt and different reaction conditions were studied. All the modifications were optimized and further analyzed. The structure of epoxy/organoclay nanocomposites was investigated by X-Ray Diffraction to evaluate the compatibility of the epoxy resin and the organoclay; the thermal and mechanical properties as well as the water absorption degree of nanocomposites with different clay contents were also investigated.