ABSTRACT
There is much literature showing that carbon black particles in vulcanized natural rubber modify the mobility of the polymer chains as a result of chemical linkages formed bet\veen the two materials. This modified polymer layer is estimated to be about 50 A in thickness. Therefore. the modulus and the ultimate strength of the filled rubber are greater than those of the unfilled one. Kraus and Gugone ]4] studied the adsorption of elastomers on reinforcing J1llcrs from solutions. analyzed the adsorption isotherms according to a statistical mechanical theory of polymer adsorption developed by Simha. Frisch, and Eirich ]5-7]. and obtained valuable information on the polymer-filler interaction responsible for reinforcement. Kwei ]8] studied the sorption of water vapor by TiO?-fil1ed and unfilled epoxy polymer, and performed a thermodynamic analysis that showed that polymer segments at a distance less than 1500 A from the surface of the filler are under the influence of the filler. Kambe and Kato [9] studied dynamic mechanical properties of a series of amorphous epoxy resin films filled with homogeneous polyethyl methacrylate (PEMA) beads with different diameters. and showed that larger increases of T" of PEMA are found for smaller particles, and that the loss peak per unit volume of PEMA is lowered with increase in the particle size. thus indicating some interactions between beads and the matrix phase. It is evident from these several examples that we need detailed knowledge of the interfacial interactions between the two phases if we want to study the physical properties of composite materials. We need to measure the physical or physicochemical properties of the composite materials as a whole, as well as those of the individual constituents. in order to know the properties of the bound polymer near the surface. which reflect the interactions between the component phases.
