MICRO-CELLULOSE FIBERS REINFORCED EPOXY FOAMS

P.M. STEFANI, C.J. PEREZ, V.A. ALVAREZ,

Rio de Janeiro, Brasil

Conferencia; 4th International Conference on Science and Technology of Composite Materials; 2007

In this work, the dynamic-mechanical behavior and compressive properties of micro-cellulose reinforced epoxy foams were investigated. Micro-celullose fibers with average diameter of 9.0 ± 2.1 mm were obtained from sisal fibers (Brascorda, Brazil) by a several step processes including chlorination, alkaline extraction, and bleaching.  Epoxy foams were prepared from the commercial system (LY 5054 epoxy resin, HY 5054 amine as curing agent and DY 5054 polydimethylsiloxane as foaming agent) supplied by Ciba-Geigy. The epoxy foam was synthesized with a epoxy:hardener:blowing agent ratio of 100:25:1 (by weight), and reinforced with low amounts of micro-fiber (0, 0.5 and 1 wt%).  It was determined from SEM experiments, that the incorporation of micro-cellulose modifies the final morphology of the foam, decreasing the average cell size (from 367 to 201 mm) and increasing the number of cells per volume unit.  As a general result, the mechanical behavior of the reinforced samples showed improvements with respect to the unreinforced foam. Whereas the compressive modulus increased a 15% for 1 wt.% of micro-fiber incorporation, the storage modulus, measured above Tg (102 ºC), was twice the value of pure epoxy foam.