Epoxy resin refers to a general term for a class of polymers containing more than two epoxy groups in the molecule. How much do you know about it? Do you know what factors affect epoxy resin?
1. The structure of the curing agent: the structure of the curing agent plays a decisive role in the curing reaction of the epoxy resin. In the compounds containing active hydrogen, the structure and basicity of the fatty amine are different from the aromatic amine. The activity of epoxy groups for nucleophilic addition reaction is: fatty amines are larger than aromatic amines. In the same series of amine compounds, primary amines are more active than secondary amines.
Epoxy resin curing agent manufacturers tell you that there is no activity on the nitrogen atom of the tertiary amine, and the density of the electron cloud to the epoxy group is low through the strong electronegativity of the nitrogen atom on the tertiary amine (there is a city bond electron pair on the nitrogen atom). The carbon atoms attack to form oxygen anions, which initiates the anionic polymerization of epoxy resins. The reaction rate of active hydrogen-containing compounds with epoxy resins is significantly greater than the reaction rate of proton-donor compounds with epoxy groups.
2. The structure of epoxy resin: Due to the difference in molecular structure, epoxy resin has different activity during curing reaction with active hydrogen compounds, proton donor compounds, synthetic resins and initiators. Epoxy resins contain electron-withdrawing groups When it is agglomerated, it will increase the reaction rate of the Lewis base curing agent and decrease the reaction rate with the Lewis acid curing agent.
When the epoxy resin molecule contains an electron-donating group, it will increase the reaction rate with the Lewis acid curing agent and decrease the reaction rate with the Lewis base curing agent