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

Abstract

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, 1H 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°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.

Performance Evaluation for Ultra-Lightweight Epoxy-Based Bipolar Plate Production with Cycle Time Reduction of Reactive Molding Process

“…As the aforementioned matter related to the effect of functionalized nanofillers on curing time reduction, the changes in existing functionalities on nanofiller surfaces and epoxy chains were investigated using FT-IR and XPS. The research literature presented the reaction mechanisms for COOH- Carbonous fillers [ 30 , 45 , 46 , 47 , 48 ] and the mechanism illustrated in Figure 3 are the reaction pathways that can be generated in our laminated composite system.…”

“…The N1s peak is described in terms of two contributions which are related to 68.92% of C- N (396.60 eV), 20.44% of N -O (397.37 eV), and 10.64% of O- N -O (398.86 eV), which are from the epoxide group crosslinked with the amine curing agent. The previous research discussed a theoretical study on the epoxide group crosslinked with the amine curing agent, the epoxy groups may be opened by acid occurring via a nucleophilic attack of the amine nitrogen on the terminal carbon of the epoxy [ 45 , 46 , 47 ]. The plasma functionalization on nanofiller surfaces was found to be an effective means to enhance the interaction between polymers and plasma-modified nanofillers owing to both physical (surface roughness) and chemical treatment (active polar groups) [ 30 , 56 ].…”