Three-dimensional models for predicting the modulus and yield strength of polymer blends, foams, and particulate composites

Two models are introduced to predict mechanical properties of two-component isotropic systems: (i) the cross orthogonal skeleton (COS) with co-continuous components and (ii) the cubic orthogonal skeleton (three perpendicular plates-3PP) with one component continuous and one discontinuous. Simultaneous prediction of the modulus and yield (or tensile) strength is based on phase continuity parameters (calculated for the two models) which serve as input data in an equivalent box model. At yielding (or breaking), the upper and lower bounds are distinguished which are related, respectively, to interfacial adhesion sufficient and insufficient for the transmission of stress inducing plastic deformation. The moduli and the upper bound of yield (or tensile) strength of the COS model, which is applied to polymer blends, are monotonic functions of composition. If partial or complete debonding occurs before yielding [or breaking], the corresponding strength passes through a minimum as a function of composition. The 3PP model renders an approximate prediction of the modulus and yield strength of closed-cell foams and particulate composites. Predicted dependences reasonably agree with those of other models and/or with experimental data from literature.