Fire Retardancy of $${{\rm Cloisite}^{\textregistered}}$$ Cloisite ® 20 Organoclay Modified Dehydrated Castor Oil-Based Alkyd Resin

Abstract

The effect of \({{\rm Cloisite}^{\textregistered}}\) 20 organoclay content on fire retardancy, mechanical and chemical properties of dried films of halogen-free alkyd resins synthesized from \({{\rm Cloisite}^{\textregistered}}\) 20 organoclay and dehydrated castor oil (DCO) were investigated. Structural elucidation of the raw and the fire-retardant resins was confirmed through Fourier transform infrared spectroscopy instrumental techniques. The DCO modified alkyd resin macromolecule was synthesized through alcoholysis–esterification interface using glycerol, phthalic and maleic anhydride. Eight samples of fire-retardant resin were produced. Samples I, II, III, IV, V and VI contain 0, 2, 4, 6, 8 and 10 % by mass of \({{\rm Cloisite}^{\textregistered}}\) 20 organoclay, respectively. Samples VII and VIII contain 4 % of weight of Cloisite 20 with 100 % PA and 3:1 ratio of phthalic anhydride and maleic anhydride, respectively. The fire retardancy was evaluated using Westgate vertical match test. It was found that fire retardancy increases with increases in \({{\rm Cloisite}^{\textregistered}}\) 20 contents without any noticeable effect on chemical resistance, but certain drawbacks with adhesive and gloss properties were observed. The best result was observed with sample IV which contains 6 % by weight of \({{\rm Cloisite}^{\textregistered}}\) 20 and showed excellent fire-retardant properties with adhesion, gloss and hardness properties of 5B, 80 and 1.8 Kg, respectively. The infrared (IR) spectra band at 1035, 921, 792, 683 and 556 cm−1 of Si–O–Si and O–Si–O stretching confirms the successful grafting of the organomodifier.