EVALUATION OF CARDANOL ACETATE AS A REACTIVE DILUENT FOR ALKYD COATINGS

Alkyd resins are viscous, tacky materials that are difficult to handle. Most often, these handling problems are overcome by dissolving the resins in organic solvents, which evaporate into the atmosphere as volatile organic compounds (VOC’s), giving rise to regulations (in many parts of the world as a way to reduce the environmental impacts). Cashew nut shells are normally burned to provide heat duringprocessing of the nut.This practice ends up in production of dark thick smoke with particulate matter which pollutes the environment profoundly. This is mainlydueto the presence of cashew nut shell liquid residue in the shells. Cashew nut shell liquid (CNSL) is not currently utilized in Kenya and the objective of this work was to develop reactive diluents from chemically modified CNSL products and evaluate their compatibility and suitability in alkyd coatings. Cardanolwas isolated from decarboxylatedCNSLusing a combination of physical andchemical methods. The cardanol acetate wassynthesized by treating cardanol with acetic anhydrideand wasalso characterized by FT-IR and it showed the presence of the C=O stretch functional group characteristic of the ester and the absence of the OH group that was present in cardanol. Cardanol acetate and neat cardanolwere tested as reactive diluents for alkyd resins in coating formulations.Cardanol acetate showed good properties, including low viscosity and good drying performance. Furthermore, a shortening of the drying time of about 25-35 % compared to conventional commercial products.