Development of Cardanol-based Phenolic Resin as Natural Adhesive for Uniting Fossil (Metacarpal Bone of Bovidae Family) Fragments
Cardanol, an organic compound contained in Cashew Nut Shell Liquid (CNSL) has been consider as one of natural resources to produce adhesive material. It could have been extracted from CNSL by simply liquid-liquid extraction method. Due to its chemical structure, cardanol has been easily converted to be phenolic resin through polymerization reaction with formaldehyde. Regarding to the necessity in reversible adhesive for initial fossil identification by archeologist and paleontologist, the obtained cardanol-based phenolic resin was then used to reunite fossil bone fragments of Metacarpal Bovidae. Identification of fossil’s compound contents conducted by X-Ray Fluorescence (XRF) showed that the fossil majorly contained CaO (56%), Fe2O3(15.33%), P2O5 (11.85%), MnO (11.17%), SiO2 (2.05%), MgO (1.47%), Al2O3 (0.67%) and other compounds (1.46%). The very hard bone fossil was firstly cut into several pieces and jointed to be three pairs using twodifferent resins, those were commercial epoxy resin, and cardanol-based phenolic resin. Those adhered fragments were then tested using Universal Testing Machine (UTM) in term of examining the strength of each resin. Different strength of both resins commercial epoxy resin and cardanol-based phenolic resin measured were 177.1, and 104 N/mm2, respectively. Although cardanol-based phenolic has the lower strength among resins, but it is reversible and practically the easier one to be applied.
Keywords - Adhesive, Fossil, Cardanol, Resin