Quantitative Evaluation Of Dispersion Of Nanoparticles In The Matrix

The performance of nanocompsites seriously depends on the dispersity of nanoparticles inthe matrix. Hence It is vital to make a quantitative evaluation of dispersity of nanoparticles in thematrix, to improve the performance and structure of nanocomposites. To make a moreappropriate quantitative evaluation to the dispersity of nanoparticles in the composites matrix,and to enable the index to represent the dispersity of nanoparticles more precisely, the paperfirstly, based on the precedent study, proposes a quantitative evaluation of particles dispersion—Stereoscopic-energy Method, which take the information of3D structure into considerationcomprehensively. The dispersity of Nano silica particles in the Silica/epoxy nanocomposites,which was selected for research, was evaluated quantitatively by the Stereoscopic-energyMethod. On this basis, observsing the thermal performance is used to demonstrate this method.To begin, Stereoscopic-energy Method was developed on the basis of the theory of surfaceenergy (the specific surface area of particle is proportional to the surface energy, which reflectsthe dispersity of nanoparticles, and as the dispersity improved, dispersion index increasescontinuously, and vice versa). In order to acquire the specific surface area of particle, stereologywas introduced from the biology realm as a solution. A dispersion index was then defined toevaluate the dispersity quantitatively. Due to the employment of both surface energy andstereology, the access method was named as Stereoscopic-energy Method.After that, Nano silica/epoxy nanocomposite materials with same content of nanoparticlesbut different dipersity, were prepared through the blending method, with PEG as a kind ofdispersing agent, nano silica particles as reinforcers and epoxy as a matrix, whose scanningelectron microscopy (SEM) cross-section diagrams was taken as for research.Through the MATLAB, the SEM diagrams were then manipulated using the method offiltering, morphological processing and threshold, to most extent, retaining the raw materialwhile highlighting the demanded information.On this basis, the three-dimensional (3D) information was effectively gained from thetwo-dimensional (2D) image, which was applied to recognize the surface energy and to obtainthe reasonable index. Compared with other current quantitative method, such as Free-path spacing Method and Segmentation Method, under various dispersion conditions,Stereoscopic-energy Method has a better universality. In addition, it has a considerablerelatedness and accuracy in the evaluation of the silica/epoxy nanocomposite materials. As thedispersity of nanoparticles in the matrix goes bad, drops the dispersion index and vice versa.Finally, through observing the thermal performance (Tg) of silica/epoxy nanocompositematerials, the rationality and accuracy of the dispersion index gained from theStereoscopic-energy Method had been demonstrated qualitatively. The consequence manifeststhat Stereoscopic-energy Method has accuracy and reliability in the quantitative evaluation ofnanoparticles in the matrix dispersity.