Mold temperature and pressure effects on tension in glass fiber–polypropylene composites.

This article focuses on developing and validating a comprehensive mathematical model to analyze fiber tension and resin flow dynamics during the melt impregnation process of glass fiber-reinforced polypropylene (GFPP) composites. The model integrates Reynolds equation, Darcy's law, and the continuity equation to predict pressure distribution, resin viscosity (modeled via an Arrhenius-type temperature dependence), film thickness variation, and fiber tension under varying mold temperatures, pressures, and film thicknesses. Experimental validation using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), alongside MATLAB simulations, demonstrated that higher mold temperatures (up to 250 °C) reduce resin viscosity and pressure gradients, leading to improved resin flow, reduced void content, enhanced fiber–matrix adhesion, and increased crystallinity in GFPP composites. The findings underscore the critical role of precise control over processing parameters to optimize impregnation quality and mechanical performance, with implications for industrial applications in automotive and aerospace sectors.