Abstract
Polymer-metal cluster composites, in which ultrafine particles of colloidal metals were well dispersed in polymer matrix, were prepared by dissolving the metal compounds in monomer, polymerization, solidification, and deoxidation by heating. From the measurement of the thermomechanical properties of polymer-metal cluster composites, the optimum condition for the heat treatment and the mechanism of elastic modulus reinforcement were discussed. The elastic modulus of the composite increased as much as two times than that of the matrix polymer by adding only 0.005 volume percent of palladium ultrafine particles with a diameter of 10-20 _??_. This peculiarity in elastic modulus increase was considered to be caused by the good unification of the ultrafine particles and the matrix. It was shown that the mechanism for the modulus increase can possibly be described based on the rule of mixture of composites taking into account the existence of interfacial binding regions. In such composite materials, it was suggested that the mechanical properties can show remarkable increase with a decrease in the diameter of particles.
