A Molecular Theory of Filler Reinforcement Based upon the Conception of Internal Deformation (A Rough Approximation of the Internal Deformation)

Abstract

Abstract A molecular theory is presented in this paper which gives a method of analysis for the mechanical properties of filler-reinforced elastomers, based upon the concept of the internal deformation and the statistical theory of rubberlike elasticity. By using a suitable model and a few new concepts a proper analysis for such a heterogeneous system is obtained. From the theory the internal mechanism of filler reinforcement is understood. It is made clear that reinforcement consists of three effects: the volume effect, the surface effect, and the cavitation effect. From the theory, formulae for the tension, swelling tension, Young's moduli, local stress distribution, strain birefreingence, condition for swelling equilibrium, and so on are derived. It has long been recognized that rubbery substances and plastic materials are reinforced by incorporation of suitable powdery substances (reinforcing fillers) which improve their mechanical properties such as elastic modulus, hardness, stiffness, resilience, solvent resistance, plastic viscosity, tensile strength, tear resistance, etc. Although numerous attempts have been made to clarify and systematize the internal mechanism of filler reinforcement, there is at present no distinct picture of the mechanism, much less a satisfactory theoretical treatment of the phenomena.