Epoxy /MMT nanocomposites, EP resin matrix has a certain amount of dispersion of the layered inorganic nanoparticles. Yin Nami unique characteristics of particles, such as small size effect, surface effect, quantum size effect and macroscopic quantum tunnel effect, resulting in organic /inorganic nano-size range in the two phases within the composite, interfacial area between the two phases is very large, the interface between has a strong interaction; the interface between two phases at this time is different from the common organic /inorganic composite, clear sharp phase boundary become blurred (paint cases can wait, 2002). The interface structure changes, the macroscopic properties of composite materials, in particular the dielectric properties of significant impact (Ge Jinlong, etc., 2009). EP
will warm up to reduce the viscosity, check the amount of EP. Learn at a certain concentration of said drying of the Cloisite (R) 15A, solvent chlorobenzene and Cloisite (R) 15A of the mass ratio of 70:1, hand shake to mix well, and then placed in the ultrasonic cleaning bath, scattered 30min . In accordance with the EP after 1%, 3%, 5%, 7%, 9%, 11% the proportion of mixing certain amount of time, the temperature at 120 ℃ under controlled conditions, to mix, continued 3h, making the solvent chlorobenzene completely volatile. At this point, the role of mechanical stirring, a large number of gas mixed with the melt mixture, melt poor light, the color is very light, but opaque. In the insulation was added under the liquid curing agent triethylenetetramine EPIKURETM3234 (epoxy resin: EPIKURETM3234 mass ratio 100:13), taking the time to degassing of molten mixture, the melt after the removal of air bubbles become darker in color, but through light is good, was transparent. After taking the time to the mixed system will be cooled to 70 ℃. Then again, taking the time to removal of vacuum bubbles, until no air bubbles within the system so far. At this point the mixture was dark red and lighter color uniform and transparent. Repeatedly taking the time to removal of the air mixing system is an important step in preparation of samples is essential. If the lack of this step, the mixture will bubble a lot of residual specimen after curing. Will melt into the 10cm × 7.5cm × 1.5cm of steel, the steel and the roof and floor are placed around the Teflon film, placed on the electric board. First, the pressure to maintain the pressure 10.5MPa, the temperature is 25 ℃, 2h; and then increasing the temperature to 45 ℃, 1h; finally, returned to ambient pressure, 8h. The samples were cut into
4.00cm × 4.00cm, test its capacitance. Test equipment: QuadTech7600PRECISIONRLCMETER. Calculated dielectric constant εr = CL/ε0S formula: L-sample thickness, unit m; C-materials, capacitance, unit F; S-electrode active area, unit m2; ε0-vacuum dielectric constant, 8.85 × 10 -12F /m. Test conditions: frequency of 1.0kHz, the voltage 1.000V. Montmorillonite modified with a different ratio obtained in the modified montmorillonite /epoxy composites and calculated the capacitance of the dielectric constant in Table 1.
epoxy /montmorillonite nanocomposites Synthesis
Shown in Table 1, pure epoxy curing agent added after the dielectric constant of 4.31, the montmorillonite content of 1% to 7%, and with the Monte off the stone content increased, the dielectric constant is increasing, when the montmorillonite content of 7%, the maximum dielectric constant of 215.35, however, continue to increase content of montmorillonite, but decreased the dielectric constant, said Ming Meng addition of stone off the best of 7%.
Use by the organic modification of montmorillonite and intercalation polymerization by compound can effectively improve the dielectric properties of the substrate, the organic reagent and the role of montmorillonite layers of the composite interface significant performance impact. When the interface is stronger, improve the performance of the composite better. Preliminary results show that: the organic dielectric properties of montmorillonite modified epoxy resin may be related to the organic was dispersed nanoscale montmorillonite layers occurred epoxy matrix caused by "lifting off" and "fiber pull" effect related.
