Continuous Glass Fiber–Polypropylene Composites Made by Melt Impregnation: Influence of Processing Method

Abstract

The efficiency of different melt impregnation methods for producing continuous glass fiber–polypropylene tapes has been evaluated. The selected methods were the common pin assisted method, a crosshead impregnation die including different vibration techniques and a slit die. The degree of melt impregnation was studied qualitatively with optical microscopy and determined quantitatively by opacity measurements. Excellent results were obtained using the radial slit die, followed by the pin chamber impregnation method. The crosshead impregnation die gave poor impregnation. With the radial slit die it was possible to achieve high fiber volume fraction and it was easy to control the fiber–matrix content. The haul off speed ranged from 1–10 m/min.