The Influence of Melt Impregnation Parameters on the Degree of Impregnation of a Polypropylene/Glass Fibre Prepreg

Abstract

The melt impregnation process to produce a high quality thermoplastic prepreg is studied. Raw materials used in the experimental work are polypropylene and glass fibre. A laboratory scale melt impregnation line is developed with a melt impregna tion die of cross head type. A methodology to determine the degree of impregnation is described. The influence of processing parameters on the degree of impregnation is evalu ated, and the process is developed to produce a well impregnated prepreg. Two different forms of thermoplastic prepreg are produced: a tow and a tape. The influence of the fol lowing processing parameters on the degree of impregnation are studied: impregnation time, polymer temperature, temperature of heated rods inside the die, use of pins inside the impregnation die in different positions, vacuum in the roving infeed stage, prepreg ten sion, MFR-value of the polymer matrix, use of coupling agents with the polypropylene matrix, ultrasonic vibration in the molten polymer and use of two different infeed geome tries of the polymer melt.