Study On Preparation And Properties Of Epoxy/Multi-walled Carbon Nanotubes Composites

Epoxy has been widely used in electronic and electric fields because of itsexcellent physical and electric properties. Though Epoxy has been used in a widevariety of engineering applications, the innately disadvantages of epoxy restrict afurther application occurred in high level. As technology advances,the innovationof the modification has been developed. Temporarily, revolutionarynanocomposites present a new approach to the research on modify bynanotechnology.Oxidized Carbin nanotubes O-MWNTs and epoxy functionalized Carbonnanotubes EP-MWNTs were prepared first, and then dispersed them into matrix ofdiglycidyl ether of bisphenol A （E-51） equably by ultrasonic and mechanicalstiring. Epoxy/MWNTs nanocomposites with different contents of particles wereprepared with O-MWNTs and EP-MWNTs respectively through solventintercalation processes.MHHPA and pyridine will play curing and catalytic agentrole respectively in this system.The dispersion of functionalized MWNTs in composites were characterizedby means of Scanning Electronic Microscopy （SEM）. Morphology of the crosssection of EP/MWNTs composites were investigated by SEM. Thermogravimetricanalyser was carried out to estimate the thermal performance of the composites.Impact strength were measured to prove the effect of the nanoparticles ontoughening, also the toughening mechanism was discussed. The temperaturedependence of composites dielectric spectrum was verified by using a scheringbridge. The influence of nanoparticles to dielectric properties of the compositeswas construed.Experimental results showed that the functionalized MWNTs make the betterdispersion than pure MWNTs, the diameter of EP-MWNTs and its dispersion wereincreased significantly than O-MWNTs. Along with the increasing mass fraction of the functionalized MWNTs, the impact strength of composites materials canimproved obviously, as the doping content of EP-MWNTs and O-MWNTs reached1.0wt%and0.7wt%, the impact strength of composites rises to themaximum,compared with the pure epoxy were increased by52.2%and39.9%respectively. The thermal decomposition temperature was not monotone raise upwith the increased concentration of functionalized MWNTs.The temperature dependence of the dielectric constant and dielectric loss ofthe MWNTs/EP composites were similar to the pure epoxy, but the dielectricconstant and dielectric loss both were increased compared to the pure epoxy, andthe O-MWNTs/EP composites increased even more sharply. In the frequencyconversion electric, with content of the EP-MWNTs increased, both the dielectricconstant and dielectric loss of the MWNTs/EP composites were increased.