A study of coating properties of biobased modified epoxy resin with different hardeners

In this study, acrylated soybean oil (AESO) was used as a modifying agent for DGEBA-type epoxy resin (ER). The structure of modified epoxy resins (M-ERs) cured with various hardeners (SAc-sebacic acid, MNA-methyl nadic anhydride, PhA-phthalic anhydride, MA-maleic anhydride, SA-succinic anhydride, cycloaliphatic polyamine Epamine PC 17, MXDA-m-xylenediamine, MI-2-methylimidazole and polyamide type Crayamid) were characterized by Fourier transform infrared spectroscopy (FTIR). Atomic force microscopy (AFM) and SEM were used to determine the microstructures of some M-ERs. DSC test was conducted to study the effects of hardners on the Tg of the M-ERs. The influence of the modifying agent and hardeners on the curing process was studied through FTIR spectroscopy, and the curing degrees of M-ERs were determined to be over 94%. To investigate the effects of the curing agents, a comparative study was also performed on the mechanical properties of neat ER, such as the tensile strength and hardness. Comparison between the mechanical properties of the epoxy systems demonstrated that the neat ER system had a higher tensile strength and e-modulus than that of M-ERs, which is in contrast to the elongation at break. Higher tensile strength values of 58 MPA and 53 MPa were observed for M-ERs cured with MNA and MXDA curing agents, respectively. A comprehensive study of the mechanical and water sorption properties of M-ERs illustrated that for an epoxy system modified with AESO in 50 wt%, MNA and MXDA were a more effective hardeners. Coatings obtained from M-ERs cured with anhydride type hardeners were determined to be highly resistant to acidic corrosive media. (C) 2016 Elsevier B.V. All rights reserved.