Study On The NanoSiO₂ Modified Epoxy Resin Curing Agent

Epoxy resin need react with curing agent as a three dimensional network in the actual application, so the structure and performance of curing agent have a direct impact on the epoxy resin curing system.This paper focus on a new curing agent can resist damp and hot environment, then add nano-silica particles to the curing agent to change the defects that brittle and easy to turn yellow. According to the requirements of curing at room temperature, we choose the diethylenetriamine (DETA) as raw curing agent material. Due to the beginning reaction rate is too quickly, which will result in great shrinkage stress and make the film become brittle and crack easily. In order to reduce the activity of polyamine curing agent, it needs to use the blocking agent E-10 to close part of the primary amine hydrogen. At the same time, it needs a certain amount of epoxy resin used as chain extender to improve the compatibility of the modified curing agent and epoxy resin. Because the viscosity of epoxy resin is higher, appropriate solvent is important for the curing agent system. Finally, when the mixed solvent that xylene:n-butyl alcohol=7:3 and molar ratio of the reactants is n(E10):n(DETA):n(E-51) =1.2: 1.0: 0.3, curing agent system is stable.Aim at the defects that brittle and easy to become yellow, we add a certain amount nano-SiO2 in the curing agent to improve the performance. Because of the special performance of nano-particles need to be modified by silane coupling agent KH-560 before add to the curing agent system. Analysis the structure of nano-SiO2 modified curing agent and contrast the dispersibility, find E-10 is the better disperse system. As the different contents of nano-SiO2 will influence the final epoxy resin system performance, we use the Differential Scanning Calorimetry (DSC) to detect the Glass Transition Temperature, further, detect the curing behavior, water resistance, tensile strength, corrosion and ageing resistance. When the contents of nano-SiO2 is 4%, the performance of modified curing film is best. Otherwise, technological conditions also have great influence on curing agent. According to the experimental data, we set the initial reaction temperature at 70oC, gradually heating, react 1h at 75 oC, react 1h at 80 oC, then vacuumpumping 20 min, the roughness and aging performance have increased significantly.