Mechanical characterisation of polyurethane/clay nanocomposites

Polyurethane/clay nanocomposites have been synthesised from renewable sources. A polyether polyol was obtained by a method involving the synthesis of palm oil-based oleic acid from glycerol. This was then used in the production of a polyurethane by reaction with an isocyanate. Dodecylbenzene sulfonic acid (DBSA) was used as catalyst and emulsifier. The unmodified clay (kunipia-F) was treated with cetyltrimethyl ammonium bromide (to form "CTAB-mont") and octadodecylamine (to form "ODA-mont"). The d-spacing in CTAB-mont and ODA-mont were 1.571 nm and 1.798 nm respectively, i.e. larger than that of the original "pure-mont" (1.142 nm). The organoclay was intercalated in the polyurethane, as confirmed by a wide angle x-ray diffraction (WAXD) pattern. The mechanical properties (including the dynamic mechanical properties) of pure polyurethane (PU) and PU/clay nanocomposites were measured. The results indicate that 1-5 wt.% of organoclay gave the most significant improvements in tensile properties and in glass transition temperature.