Polyamidoamines based on castor oil-styrene co-oligomer/triethylenetetramine as curing agents in high-performance epoxy coatings

摘要

Polyamidoamines (PAMAMs) based on castor oil-styrene co-oligomer and triethylenetetramine (TETA) or benzylated TETA were synthesized and diluted with an amide-like diluent (EFA). The intermediates and products structures were characterized using FT-IR, H-1 NMR, gel permeation chromatography, and scanning electron microscopy. The diluted PAMAMs types were used as the curing agents of the epoxy resin to produce the modified coatings. The mechanical, chemical, and visual properties of the epoxy coatings obtained by commercial hardeners compared to the modified coatings. The modified coatings were transparent, and had humidity resistance higher than the commercial coatings, at 15 degrees C and 80% relative humidity. The modified coatings were obtained with the lowest surface defects and improved mechanical properties such as Izod impact resistance, tensile strength, and the pull-off adhesion (3.3-4.8 kJ m(-2), 42.2-54.5 MPa and 3.0-3.5 MPa) relative to the commercial coatings (1.1-3.0 kJ m(-2), 28.7-39.9 MPa and 1.4-2.1 MPa), respectively. Moreover, in spite of the commercial coatings, the modified coatings were cost-effective and showed the behaviors of appropriate self-healing and chemical resistance.