A novel star-shaped, cardanol-based bio-prepolymer: Synthesis, UV curing characteristics and properties of cured films

Starting from renewable Cardanol, a novel inherently fire-retardant UV curable bio-based prepolymer (AEHCPP) with phosphazene core and six Cardanol arms are prepared in this report. The chemical structure of all newly prepared intermediates compounds and AEHCPP are well-characterized using nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). UV-curable mixture consisting of AEHCPP and different diluents were formulated and their photopolymerization dynamics were investigated on Photo-calorimetry (photo-DSC). The thermal properties of crosslinked coatings were estimated using thermal analysis technology. Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) results show that glass transition temperatures of all cured films are above room temperature (>30 degrees C), the 5% weight loss temperature in nitrogen is higher than 266 degrees C. The fire-retardant properties are estimated by TGA and all calculated Limiting Oxygen Index (LOI) values are over 24, implying the excellent fire-resistance of cured films. (C) 2018 Elsevier Ltd. All rights reserved.