Green methacrylated lignin model compounds as reactive monomers with low VOC emission for thermosetting resins

Abstract

Methacrylated lignin model compounds (LMCs, i.e., eugenol and guaiacol) monomers are ideal candidates as styrene replacements because they have low volatilities and can free-radically polymerize with vinyl ester resins. This article reports the synthesis of methacrylated eugenol (ME), methacrylated guaiacol (MG) using LMCs and methacrylic anhydride in the presence of 4-dimethylaminopyridine (DMAP) as a catalyst. ME and MG were characterized using FT-IR, 1H-NMR and 13C-NMR. The thermal and mechanical properties of the samples prepared at 30°C from o-cresol epoxy based vinyl ester resin (VEOCN) using MG and ME, respectively, as reactive monomers, in the presence of benzoyl peroxide (2 phr) as initiator were further investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA/DTG/DTA) and universal testing machine (UTM). Chemical and corrosion resistance of cured VEOCN samples coated on steel panels were also evaluated as a function of percentage weight loss and with the help of scanning electron microscopy (SEM), upon immersing the VEOCN samples in 1 m HCl, 1 m NaOH and 1 m NaCl solutions for 90 days. Thermal, mechanical and chemical performance of VEOCN using ME and MG was also compared with VEOCN samples containing styrene and methyl methacrylate (MMA) as reactive monomers.

Keywords

• chemical and corrosion resistance
• crosslinking
• environment sustainability
• reactive monomers
• renewable resources
• thermal and mechanical performance