Synthesis and performance of intrinsically flame-retardant, low-smoke biobased vinyl ester resin

In order to obtain an intrinsically flame-retardant vinyl ester resin from renewable resources, a biobased vinyl ester resin monomer 5,5′-dially-[1,1′-biphenyl-2,2′-diyl bis(2-methylacrylate) (DBDBMA) was prepared from magnolol and methacryloyl chloride by a one-pot method. The DBDBMA structure was confirmed by Fourier transform infrared spectroscopy, ¹H and ¹³C nuclear magnetic resonance and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The biobased DBDBMA was cured with 20 wt% styrene to get DBDBMA system. The initial decomposition temperature of DBDBMA system was 400 °C and the char residues was 16% at 800 °C in N₂. The cured DBDBMA system exhibited an outstanding intrinsic flame retardancy with a high limiting oxygen index value of 33% due to excellent char-forming ability. Compared with existing commercial vinyl ester resin，the total heat release and smoke production of the DBDBMA system decreased by 33% and 37.7%, respectively. Besides excellent intrinsically flame retardancy performance, DBDBMA system also showed good transparency. The results suggest DBDBMA system is a kind of intrinsically flame-retardant, low-smoke vinyl ester resin with excellent comprehensive performance, which provides a new idea for the development of vinyl ester resin in the future.