A novel flame retardant UV-curable vinyl ester resin monomer based on industrial dipentene: Preparation, characterization, and properties

A novel bio-based and flame-retardant UV-curable vinyl ester resin (VER) monomer named Diglycidyl ester of maleinized dipentene modified with dibutyphosphate and methacrylic anhydride (MDDMD) was synthesized from industrial dipentene via Diels-Alder reaction, glycidylation, epoxy ring-opening reaction, and esterification. Its chemical structures were characterized by Fourier transform infrared (FTIR) analysis and proton nuclear magnetic resonance (H-1-NMR). In order to improve its flexibility, we prepared a series of copolymers under UV light radiation by mixing it with certain proportions of poly(ethylene glycol) dimethacrylate-200 (PEGDMA-200) which contained flexible groups. Their tensile property, curing degrees (CD), hardness, limiting oxygen index (LOI), dynamic mechanical thermal properties, and thermostability were all investigated. The cured mixed resins have a relatively high tensile strength of 10.05 MPa and curing degrees up to 92.5%. Both hardness (range: 50 to 23 HD) and LOI (range: 22.8% to 24.4%) of cured resins are improved with the increase of MDDMD content. Dynamic mechanical analysis (DMA) shows that their glass transition temperatures rise with the increase of MDDMD content. Thermogravimetric analysis (TGA) shows that the thermal stability of cured resins is enhanced with the increase of PEGDMA-200 content, as the main thermal initial decomposition temperatures are all above 260 degrees C and char yield at 800 degrees C are above 18.10%. (C) 2016 Wiley Periodicals, Inc.