| Epoxy resin(EP)composites are attracted attention for their excellent heat and corrosion resistance as well as their light weight and high strength mechanical properties,which are widely used in building construction,aerospace and other fields.The traditional heat conduction curing has problems such as low heating efficiency and high energy consumption,which restrict the further production and development of epoxy resin.Therefore,efficient and uniform curing has been an important research direction in the industrialized production of epoxy resin materials.Microwave curing has the advantages of low energy consumption and rapid curing,which is suitable for the curing of epoxy resin materials.The dielectric properties of epoxy resin are an important indicator of its microwave responsiveness,and the excellent dielectric properties of ionic liquids make them potentially valuable as microwave absorbing materials.Many studies have been conducted on the microwave absorption ability of ionic liquids and their epoxy resin curing properties,but few reports have investigated the mechanism and application of the correlation between them.In this paper,a multifunctional ionic liquid 1-aminopropyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide(n IL)with curing,catalytic and microwave responsiveness was synthesized.The promotion effect of n IL on the curing of epoxy resin and its curing activity in epoxy system were investigated to achieve the structural-functional integration of ionic liquids.Meanwhile,the microwave responsiveness of n IL and its influence mechanism on the microwave curing of epoxy resin system in microwave environment were investigated in depth,the performance differences and curing kinetics of the cured products of epoxy resin system under microwave curing and traditional thermal curing process were studied systematically in comparison.The main research contents are as follows:(1)The ionic liquid n IL was successfully synthesized by a one-step method,and the target product was characterized by fourier transform infrared(FTIR)and mass spectrometry(MS).(2)The enhancement mechanism of the curing activity of the ionic liquid on the epoxy resin system was investigated,and the curing system was determined using the variable temperature DSC method.The T_gof the EP/n IL cast body sample reached 119.1℃,and the terminal amino group of n IL was involved in the curing reaction of the epoxy resin during curing.(3)The curing kinetics of EP/DETDA/n IL system was investigated by DSC method,and the apparent activation energy,E_α,of the system was calculated based on the theory of Kissinger equation,and the addition of n IL could significantly reduce E_α(-13.1%),confirming that n IL has a facilitating effect on the curing of the system.n IL has significantly improved the mechanical strength of the system,with a maximum increase of tensile strength 24%,n IL curbed the microcrack expansion at fracture,which was the key factor for the significant increase in strength,and improved the thermal stability of the system at high temperature.(4)n IL reduced the microwave curing time of the epoxy resin system by nearly half,infrared thermography showed that n IL maintained the system at a higher response temperature.The higher dielectric constant and ionic conductivity are the keys for n IL to significantly improve the microwave responsiveness of the epoxy resin system,and the experiments show that the amino ionic liquid exhibits multiple functionalities in microwave curing. |
PDF Full Text Request