Synthesis of acrylated cardanol diphenyl phosphate for UV curable flame-retardant coating application. (December 2019)

• Record Type: Journal Article
• Authors: Phalak, Ganesh; Patil, Deepak; Patil, Ajit; Mhaske, Shashank
• Is Part Of: European polymer journal. Volume 121(2019)
• Publication Date: 2019-12
• Subjects: Renewable materials -- Cardanol -- UV curable -- Flame retardancy -- Biobased coatings; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2019.109320
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: Cardanol based phosphate has been synthesized and employed as a renewable flame-retardant reactive diluent for UV cured coatings. Highlights: Acrylated cardanol diphenyl phosphate (ACP) was successfully synthesized. The flame-retardant coating was prepared by UV curing with urethane acrylate and ACP. Effect of increasing ACP content on coating properties was studied. The degree of graphitization of char residue was estimated from Raman Spectroscopy. Abstract: Acrylated cardanol diphenyl phosphate (ACP) was synthesized via epoxidation of unsaturation in long side chains of cardanol, followed by acrylation of epoxidized cardanol and, phosphorylation of acrylated cardanol. The chemical structure of synthesized products was confirmed using Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance spectroscopy ( 1 H NMR, 13 C NMR and, 31 P NMR) and gel permeation chromatography technique (GPC) respectively. The effect of increasing content of ACP into UA oligomer on viscosity of coating formulations was studied using rheometer analysis. The properties of UV curable coatings were determined by differential scanning calorimetry (DSC), X-ray diffraction analysis (XRD) and, thermogravimetric analysis (TGA). The flammability of UV cured coatings were analyzed by limiting oxygen index (LOI) and UL-94 vertical burning test. TGA result shows that the introduction of ACP into UA oligomer promotes degradation of UA oligomer and enhances the char formation. The structure of obtained char residues was further investigated from scanning electron microscopy (SEM), FTIR and Raman spectroscopy analysis. These cardanol based reactive diluent is promising candidates for UV flame retardant UV curable coatings because of their unique structure contains rigid benzene rings, phosphate moiety, polar hydroxyl groups, and long aliphatic chains.