Enhancement of Mechanical and Thermal Properties of Injection-Molded Polypropylene Parts Using Glass Fibers

Document Type : Original Article

Authors
Mohammad Reza Ebrahimian 1
Farzad Rahmani 1
Hamed hajnasiri 2
1 Assistant Professor, Department of Mechanical Engineering, Kar Higher Education Institute, Qazvin, Iran
2 M.Sc. Student, Department of Mechanical Engineering, Kar Higher Education Institute, Qazvin, Iran
10.22034/stme.2025.532480.1141
Abstract
This study investigated the improvement of mechanical and thermal properties in polypropylene matrix composites by adding glass fiber reinforcement. The results showed significant outputs in several tests. The addition of reinforcing particles resulted in a decrease in yield strain, while causing significant changes in yield strength. Charpy impact tests showed different energy absorption. This study investigated the effect of adding glass fibers with different L/D ratios (250, 300, 350) on the mechanical and thermal properties of injection molded polypropylene composites. The samples were produced by twin-screw extrusion and injection molding and tested according to ISO and ASTM standards. The results showed that the sample with 30% glass fibers (L/D=350) had the highest yield strength (98.6 MPa), impact energy absorption (14.1 kJ/m²), and thermal deflection temperature (151.7°C), and the shrinkage was reduced to 0.26%. These results indicate the potential of these composites for engineering applications with high dimensional accuracy. In addition, the addition of glass fibers resulted in a decrease in the melt flow index, while other particles showed the least effect.
Keywords
Polymer composites
Reinforced polypropylene
Mechanical properties
Composite additives
Glass fibers
Subjects
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  • Receive Date 03 July 2025
  • Revise Date 26 July 2025
  • Accept Date 14 September 2025
  • First Publish Date 14 September 2025
  • Publish Date 23 July 2026

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