Research On Toughening Epoxy Resin And Its Damping Property

Epoxy resins are widely used thermosetting matrices for advanced composites due to their good specific strength and chemical resistance, but their damping properties and toughness still need to be improved. Therefore, it's necessary to toughen the epoxy resin, and to improve the damping performance of the epoxy resin-based composite materials.Using ETBN to toughen epoxy resin, and then the mechanical property of the toughening epoxy resin casting molding system is studied. It shows that with the content of ETBN increasing, the flexural strength, tensile strength and tensile modulus decreased, while the impact strength and elongation at break distinctly increased, which demonstrates that the toughness of the epoxy resin system could be improved effectively by adding ETBN. The SEM analysis shows that ETBN is dispersed in the epoxy resin system during the curing process.Using Ethylene glycol diglycidyl ether 669 as a diluent, this paper studies how varying the overall amount of diluent influences the Epon828/T403 curing system's viscosity, damping and mechanical properties. Study shows that 669 can significantly reduce the viscosity of bisphenol-A epoxy resin to improve its operability. The mechanical properties of Epon828/669 maintained well. The retention of tensile strength, flexural strength and impact strength of Epon828/669 system with mass ratio of 80/20 were high. When the mass fraction of 669 is 20%, the damping property is the greatest. In addition, with increasing test frequency, tan8-T frequency moves to high temperature, and tanδpeak increases.Then the multi-walled carbon nanotubes were chemically modified by a 3:1 mixture of concentrated mixture of sulfur acid/nitric acid to get the acid treatment of carbon nanotubes. The micro-structure characterization is investigated by FT-IR and TEM. The results show that the carbon nanotubes have been successfully grafted onto the surface of carboxyl, and the process will not damage the functionalized carbon nanotube structure itself. With epoxy resin as matrix and carbon nanotubes as reinforcements, carbon nanotubes/epoxy resin nanocomposites were prepared by vacuum casting method. The results show that when the carbon nanotube's content is 0.75wt.%, the mechanical properties of composite materials is the best. With adding the modified carbon nanotubes, the glass transition temperature increased and the damping capacity is improved.