The effects of injection molding on the mechanical behavior of long-fiber reinforced PBT/PET blends

Long-fiber reinforced thermoplastics have received much attention because of their processability by conventional technologies for thermoplastics. However, fiber degradation represents a major problem. This work has been undertaken with the objective of investigating the effects of injection molding parameters on fiber degradation and fracture performance in PBT-PET blend/glass fiber composites. The influences of six parameters and their interactions are analyzed, i.e. peak cavity pressure, holding pressure, back pressure, screw speed, melt temperature and barrel profile. The results show that most of the molding variables, as well as their interactions, affect the properties of the composite. Fiber-length retention is not the sole parameter to be optimized; the matrix system is also affected by molding conditions and has significant effects on composite properties. The influence of the composite microstructure, which is controlled by the molding process, on the rigidity, strength and toughness of the composite is also discussed.Peer reviewed: YesNRC publication: Ye