MECHANICAL AND THERMAL CHARACTERIZATION OF XD-GRADE CARBON NANOTUBE/EPON 862 PROCESSED BY DUAL PHASE DISPERSION TECHNIQUE

摘要

Proper dispersion of carbon nanotubes is essential in attaining optimal results for nanocompositematerials. In this research, a dual-phase dispersion method combining a high intensity ultrasonicliquid processor with a three roll milling technique is studied. Xd-grade carbon nanotubes (xd-CNTs) were infused into Epon 862 epoxy and then mixed with epicure curing agent W using ahigh-speed mechanical agitator. To reduce the formation of voids, the mixture was preheated andplaced in a vacuum oven to remove trapped air and reaction volatiles. Mechanical and thermalanalyses were performed to assess improvements when combining these two dispersion methods.Flexural and dynamic mechanical analysis (DMA) were performed on neat, 0.015 wt.%, and0.15 wt.% xd-CNT/epoxy plaques to identify the loading effect on the mechanical properties ofthe composite materials. Flexural tests were performed using Zwick Roell 2.5. Flexural resultsindicated homogeneity with improvements in mechanical properties of up to 15% in strength aswell as modulus enhancement of up to 25%, respectively. Interfacial adhesion and dispersion areimproved with viscosity reduction while utilizing the secondary mixing method. Scanningelectron microscopy (SEM) was performed using Joel 2001 at 5 and 10kV. Micrographsdepicted the fracture morphology of the tested specimens indicating proper dispersion of the xd-CNTs by fracture propagation and cleavage plane displacement. Dynamic mechanical analysis(DMA) was performed using TA Instrument Q800. DMA studies revealed an increase in storagemodulus in the nanophased specimens as CNT loading increased, mainly attributed to enhancedCNT dispersion and distribution causing reduced polymer chain movement causing increasedstiffness. Thermal analysis was performed using thermogravimetric analysis (TGA). TGAresults revealed minimal reduction in decomposition temperature despite the increase of xd-CNTs.