Synthesis of a multifunctional hard monomer from rosin: the relationship of allyl structure in maleopimarate and UV-curing property

Rosin is an important forestry resource with a specific three-membered phenanthrene ring structure, which can improve the mechanical resistance of polymer coatings. In this paper, a high purity rosin monomer, tri-allyl maleopimarate containing three allyl groups has been synthesized. The yield of the monomer product was 93.2% with the purity of 96.1%. The structure of the synthesized monomer was characterized through gas chromatography (GC), mass spectrometry (MS), hydrogen nuclear magnetic resonance spectroscopy (1H NMR), carbon nuclear magnetic resonance spectroscopy (13C NMR) and elemental analysis. Additionally, we present new experimental results regarding the polymerization reaction under ultraviolet (UV) irradiation. The cured film of tri-allyl maleopimarate exhibited good mechanical properties. The films were also characterized through thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses and a mechanism for polymerization was proposed. Overall, a facile catalytic process for the valorization of rosin in the field of UV polymerization is reported.