Abstract
The effect of particle size on Young's modulus was studied for composites prepared from glass beads and either epoxy resin or unsaturated polyester. For the both composites, Young's modulus increases as the particle size decreases. This dependence of particle size on Young's modulus can be explained by Kerner's equation in which the modifying coefficient of volume fraction of filler, ψ, takes the immobilized matrix at the interface into consideration. ψdecreases almost linearly with increasing particle size and is given by the following formula: ψ=ψ0-βR, where R is the average radius of particles, ψ0 and β are constants determined by the combination of matrix and filler, and by the conditions at the matrix-filler interface.
