Study On Preparations And Properties Of Epoxy/Montmorillonite Nanocomposites

For the excellent properties performed in material mechanics, electrical insulating, adhesion and diversiform workability, epoxy is celebrated and holds a dominant position in global three universal thermoset plastics. Though Epoxy has been used in a wide variety of engineering applications, the innately disadvantages of epoxy restrict a further application occurred in high level. The rapid increment of engineering applications developed with technologies call much more rigid claims to the epoxy manufactures. Temporarily, revolutionary nanocomposites present a new approach to the research on modify by nanotechnology. It has been proved by researches that compounding the resin with nano-inorganic particles into nanocomposites can increase the comprehensive properties of the resin saliently.Epoxy/organic-montmorillonite nanocomposites with different contents of inorganic particles were prepared by diglycidyl ether of bisphenol A, with surface modified montmorillonite as modifying agent, methylenadic anhydride as curing agent, through solvent intercalation and melting intercalation processes, respectively.The intergallery distance of montmorillonite was measured by X-ray diffraction before and after exfoliation. The interphase morphological character of the fracture surface on specimen was characterized by scanning electric microscopy. The effect of different process on morphology structure was investigated. Thermogravimetric analyses were carried out to estimate the thermal performance of the composites, and the heat deflection temperature was measured to notarize the results. Impact strength were measured to prove the effect of the nanoparticles on toughening, also the toughening mechanism was discussed. The temperature dependence of composites dielectric spectrum was verified by using a Schering bridge. The influence of nanoparticles to dielectric properties of the composites was construed.Some conclusions were drawn by analyzing the results received from all of the tests. Exfoliated composites could be prepared via a solvent intercalation process, either a melt intercalation process. The clay layers were found cannot be separated further in the duration of mechanic stirring because of the agglomeration generated. The thermal decomposition temperature was not monotonic raise up with the increased concentration of nanoclay. It performed a complicated tendency. Also, the heat decomposition temperature fallen down because of the solvent left in the specimen prepared through the solvent intercalation process. The shear yielding of the matrix was speculated as the toughening mechanism by observing the fracture behavior occurred in the impact strength test. The dielectric constant and dielectric loss were decreased compared to the pure epoxy. The temperature dependence of the dielectric constant and dielectric loss of the composite is similar to the pure epoxy, however, the montmorillonite could delay the increase of dielectric loss as the temperature increase. The main reason may be layered montmorillonite restrained the polarization of the polar group in the matrix.