Evaluation of Elastic Modulus of Nano Particles in PMMA/Silica Nanocomposites
Qing-Qing Ni, Yaqin Fu and Masaharu Iwamoto
Abstract:The properties of organic/inorganic nanocomposites are determined by the performance of an inorganic particle and organic matrix. Thus, it is important to clarify the mechanical properties of inorganic particles in nanocomposites. However, since the size of a particle is very small even at a nano order, it is difficult to measure their properties. In present paper, PMMA/Silica nanocomposites were innovated by in-situ polymerization. In order to calculate the modulus of elasticity of inorganic particles in the organic/inorganic nanocomposites, the inverse analysis of equivalent inclusion method (EIM) was proposed. Using this numerical analysis, the modulus of elasticity for the silica particles was calculated. It was found that the modulus of elasticity was kept almost unchanged within about 8 % of the silica particle volume fraction and it was increased greatly when its particle size became to be a nano order. This result was reasonable and has also been confirmed and compared with the three phase model. With the results obtained, it is also shown that the proposed method is effective for the prediction of the modulus of elasticity for inorganic particles in nanocomposites. Key Words:Organic/inorganic nanocomposites, Sol-gel method, Elastic modulus, Micromechanics, Equivalent inclusion method