Cardanol-modified alkyd resins: novel route to make greener coatings

Abstract: Cardanol, which is a natural phenolic oil, is issued from Cashew Nutshell Liquid (CNSL), a non-edible renewable resource, co-produced from cashew industry in large commercial volumes (1Mt p.a.). Cardanol is non-toxic and particularly suitable for the addition of aromatic renewable resources in polymers and materials. We recently reported various routes for the synthesis of di- and poly-functional building blocks derived from cardanol thereafter used in polymer syntheses [1]. Novel alkyd resins have been synthetized with mono- and di- functional cardanol monomers. This study has demonstrated that those monomers could replace some of the monomers used in alkyd resins, which were petrosourced. Indeed, the renewable carbon contents have been increased by up to 12 %. The introduction of cardanol highly increased the thermal stability of alkyd resins [2].
Additionally, novel phosphorylated cardanol molecules based on phosphonate (PO₃CR) and phosphate (PO₄CR) functions were synthetized. Those molecules had two main actions: the reduction in volatile organic compounds (VOC) and the development of flame retardant (FR) properties conferred to alkyd resins used as coatings for wood substrate [3].
Refs

1. C Voirin, S Caillol, N V. Sadavarte, B, V. Tawade, B Boutevin, PP Wadgaonkar, Polymer Chemistry, 5 (2014), 3142-3162
2. M Denis, D Le Borgne, S Caillol, C Negrell, Progress in Organic Coatings, 2022, 172, 107087-107095
3. M Denis, D Leborgne, R Sonnier, S Caillol, C Totee, C Negrell, Molecules, 2022, 27, 4880-4898