Polymer Melt Impregnation of Glass Roving

Much attention has been recently focussed on the melt impregnation of thermoplastic polymers as a consequence of the difficulty involved in driving viscous polymer melt into a tightly packed fiber bundle. This work studies an impregnation process consisting a series of staggered cylindrical pins in a melt pool. A numerical model for evaluating the pressure generation in the wedge region between the roving/pin, the impregnation velocity of the melt through the glass mesh, and the resulting impregnation depth along the wedge is developed using relationships for pressure build-up in foil bearings and Darcy's law. The model results are compared with experimental melt impregnation data. The model adequately predicts the effect of melt impregnation process conditions on impregnation quality.