Effects of formulation variables on density, compressive mechanical properties and morphology of wood flour-reinforced phenolic foams

The influence of formulation variables of wood flour-reinforced phenolic foams (WRPFs) on density, compressive mechanical properties and morphology of the material was studied applying an experimental design. Variables studied were wood flour weight fraction (1.5–8.5 wt.%) and blowing agent amount (1.5–3.5 wt.%). The responses were apparent density and compressive modulus and strength of the material. Morphology of the foams was also observed using scanning electron microscopy and cell size distributions of the materials were determined. The incorporation of 1.5 wt.% of wood flour in phenolic foams leads to obtain a reinforced material with a compressive modulus and strength 130% and 154% of the values of the unreinforced foam, respectively, as well as to reduce blowing agent amount required for foam preparation.