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

Thermoplastic fiber-reinforced composites such as glass fiber-reinforced polypropylene are essential in industrial applications for their excellent mechanical properties, thermal stability, and recyclability. The aim of this research is to explore the influence of mold temperature, pressure, and film thickness on fiber tension in melt impregnation process of glass fiber-reinforced polypropylene composites; a mathematical model was developed using the Reynolds equation, Darcy's law, and the continuity equation to evaluate pressure distribution, resin flow, and fiber tension under varying conditions. The model predictions were validated through experimental results including differential scanning calorimetry and scanning electron microscopy. The experimental results show that a higher mold temperature of 250°C improves impregnation quality, reduces void content, and enhances the bonding between glass fibers and the polypropylene matrix. MATLAB simulation showed a direct relationship between pressure, temperature, and film thickness in controlling fiber tension. These findings highlight the critical role of precise processing parameter control in achieving optimal impregnation quality, providing valuable insights for industrial applications in thermoplastic composites manufacturing.