Initial dispersion mechanisms of chopped glass fibers in polystyrene

Understanding the mechanisms contributing to the initial stage of dispersion for individual fibers from chopped glass bundles is important for optimizing process conditions and obtaining fiber composites with optimal properties. These studies have shown that under model flow conditions, bundles have two separation modes, rupture and erosion. Both of these occur in a stochastic manner and are dependent upon the internal structure of the bundles. Under chaotic flow, both strain rate and total strain to which the material is exposed are important, though the effect of increasing strain rate decreases at higher total strains. To Obtain consistent minimal dispersion in model flows, the maximum nominal stresses required are higher than 10 4 Pa for simple shear and 10 6 Pa for squeezing flows. In contrast, stress levels around 10 4 Pa yield good dispersion under chaotic flow, implying the flow field is a more significant factor than the stresses imposed.