Fracture mechanical model for tensile strength of particle reinforced elastomeric composites

• The measured tensile strength increased with increasing particle loading and decreased with increasing particle size.
• A fracture mechanical model to predict the tensile strength/fracture toughness was developed to better understand the reinforcing effects of the particle.
• The model predicted that the size of the poor interface up to 30° of the debonded angle on the tensile strength becomes less severe as the particle size is decreased. In addition, the specimen with smaller particles (<30 µm) should have a higher tensile strength than that of the experimentally measured values.

The tensile strength of particle reinforced elastomeric composites (PRECs) was studied as functions of the particle volume content (loading) and particle size. The measured tensile strength increased with increasing particle loading and decreased with increasing particle size. The measured fracture toughness increased with increasing particle size. A fracture mechanical model to predict the tensile strength was developed to better understand the reinforcing effects of the particle and to provide a criterion for a better composite. Using a body center cubic (BCC) crystal system, the elastic energies of the undamaged and damaged cells were obtained. The tensile strength as a function of the measured fracture toughness (J value) and the modulus of the matrix can be calculated by comparing the energies. The predicted tensile strength decreased with increasing particle size in a similar manner to the experimental results. The analytical model predicted that the size of the poor interface up to 30° of the debonded angle on the tensile strength becomes less severe as the particle size is decreased. In addition, the specimen with smaller particles (<30 µm) should have a higher tensile strength than that of the experimentally measured values. The conglomeration and non-uniform distribution of smaller particles, and the entrapped void within the agglomerates while mixing and fabricating can be one reason.