Complete Fiber Orientation Analysis for a Short Glass Fiber Reinforced Center-Cated Disk Using the Shadow Optical Microscopy Analysis

Short fiber reinforced thermoplastics are a feasible alternative to develop lightweight materials for semi-structural applications. These materials present a layered structure showing a complex fiber orientation disbribution along the molding. The detailes of fiber orientation in a center-gated disk with diameters of 1.38 and 2.05 mm were characterized by combining an experimental method developed to reduce the ambiguity problem with in-house program. Two fiber suspension (30 % short glass-fiber PBT and PP) with different rheological characteristec were used in this experiments. The results showed an asymmetric distribution of fiber orientation that gradually washout as the flow progress. In addition, the initial orientation measured at the gate presented a fiber distribution different than the random orientation as is typically assmed in center-gated disk. The fiber orientation, shape and contact angle were also measured in the front region.