Morphological characterization of simulated polymer blends by light scattering

The morphology and the properties of polymer blends are closely related to processing conditions. A skin/core morphology, with a minor phase undergoing variations in orientation and aspect ratio from the surface to the core of the material is observed in processes such as the injection molding of blends. The use of optical inspection to control the stability and the quality of the product on-line is an interesting tool. In this paper, polymer composites made from glass fibers and glass microspheres embedded in a matrix of PS are used to simulate two-phase polymer blend morphology with a skin/core configuration. The relationships between the morphology of two-phase systems and the diffuse pattern scattered from an incident light beam are investigated through an analysis of the iso-intensity plots. Information can be obtained from the ratio of the axes of the ellipsoidal iso-intensity domains for depth-invariant blend morphology, and from the variation of this ratio as a function of the distance from the center of the pattern for depth-varying morphology samples. It is shown that one can differentiate the skin morphology and thickness effects.