Adhesion efficiency between phases in fibre-reinforced polymers by means of the concept of boundary interphase

Summary The role of the boundary interphase on the adhesion efficiency between fiber and matrix in the case of polymers reinforced with unidirectional fibers was investigated. A theoretical model was introduced considering that the composite material consists of three phases; that is, the fiber, the matrix and the interphase, material which is the part of the polymer matrix lying at the close vicinity of the fiber surface. The interphase material, having different physical properties from those of the bulk matrix, affects the overall behavior of the composite. Moreover, the quality of adhesion between the two main phases depends greatly on the nature of the interphase material. In this study we have considered that the interphase material is inhomogeneous in nature, with properties varying continuously from the fiber surface to the bulk matrix. The theory developed resulted in a criterion of the adhesion quality and in a prediction of the longitudinal modulus of elasticity of the fiber-composite.With 4 figures and 1 table