Synthesis of the bio-based alternative to Bis-GMA and its application to photo-polymerizable adhesives

Photo-polymerizable compound with isosorbide core attached by glycidyl methacrylate (Iso-GMA) was synthesized from bio-based isosorbide via two step reactions to replace bisphenol A-glycidyl methacrylate (Bis-GMA), and its photo-polymerizing behaviors and mechanical properties after photo-polymerization were investigated. The viscosity of Iso-GMA was lower than that of Bis-GMA, and the glass transition temperature (Tg) of photo-polymerized Iso-GMA was relatively high (80.5°C) although there was no aromatic moiety in the molecule. The photo-polymerizing pattern of Iso-GMA was analyzed by photo-DSC and FTIR, and it showed a similar photo-polymerizing rate to Bis-GMA/triethylene glycol dimethacrylate (TEGDMA) composition (6:4, w/w). The shrinkage ratio of Iso-GMA during photo-polymerization was less than that of Bis-GMA/TEGDMA (5% vs 7.2%). In addition, the adhesion properties, compressive strength, and flexural properties of photo-polymerized Iso-GMA were comparable to those of Bis-GMA/TEGDMA. Bio-based Iso-GMA could be a feasible alternative to problematic Bis-GMA that widely used in a variety of applications.