Abstract:The first quasi-static stretch of the two limiting systems of filler loaded rubber have been investigated. One of them is found by filler to matrix contacts only, the other by crosslinking permanently the matrix. In this case filler-matrix contacts are made by adhesion. The experimental results were described in terms of an extended van der Waals approach. It is illuminated that different filler to matrix contact (permanent bonds or adhesion) lead to different deformation mechanism, substantially affecting the "reinforcement". Moreover, filler induced local "field-modifications" due to the boundary value problem can be understood with the Einstein-Smallwood approach independent of the kind of the filler to matrix contacts.