Effect of new nonionic curing agent on curing kinetics and mechanical properties of epoxy resin

Abstract

The current research work presents a novel nonionic curing agent (AEDA) synthesized by utilizing ethylene glycol diglycidyl ether (EGDE), 3,4‐dimethoxyaniline (DI), and triethylenetetramine (TETA). Infrared spectroscopy and nuclear magnetic resonance spectroscopy were used to characterize the structure of AEDA curing agent. Non‐isothermal scanning calorimetry was used to determine the activation energy and curing conditions of epoxy resin in the curing process. An impact testing machine, a tensile testing machine and a scanning electron microscope (SEM) were used to analyze the impact strength, tensile strength, bending strength, and micromorphology of the AEDA/E‐51 system with different mass ratios. The results show that AEDA is an effective high‐temperature curing agent. For the AEDA/E‐51 system with the optimal mass ratio of 10:100, the best curing temperature is 92.15°C, and the post‐curing temperature is 135.65°C. Furthermore, the apparent activation energy (Ea) of 1670 J/mol, the pre‐exponential factor (A) of 3.7 × 10−4, and the reaction series (n) value of 0.76 are obtained for the AEDA/E‐51 system. The impact strength of AEDA/E‐51 epoxy resin polymer is 7.82 kJ/m2, tensile strength is 14.2 MPa, and bending strength is 18.92 MPa. The micromorphological results of the AEDA/E‐51 system are consistent with the results of DSC test and mechanical properties test. Hence, this study provides theoretical support for the practical applications of AEDA as curing agent.

Improve the Crosslinking Reactivity of Nitrile: Design of Nitrile‐Functionalized Pyrazine and its Hydrogen Bond‐Assisted Nucleophilic Enhancement Study

“…Subsequently, the model compound PZN was synthesized through the nucleophilic substitution reaction of 5-chloropyrazine-2,3-dicarbonitrile (4) and 4phenylphenol (5). Figure 1a,b shows the 1 H NMR and 13 C NMR spectra of PZN, respectively. Each atom could be assigned and the integral area of peaks in 1 H NMR spectrum matches the actual number of hydrogen atoms.…”

“…[3,4] In materials science, crosslinking reactions are widely used in the preparation of gel materials, 3D DOI: 10.1002/marc.202300199 printing materials, and thermosetting resins, among others. [5][6][7][8][9][10][11][12][13][14][15] However, some crosslinking reactions, such as those based on nitrile chemistry, still face the challenge of harsh reaction conditions, which limit their application. [16,17] Enhancing the reactivity of nitrile is crucial for expanding the application of 3D crosslinking materials.…”