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Effect of particle size, shape, and weight percentage of hydroxyapatite (HA) on rheological behaviour of polycaprolactone/hydroxyapatite (PCL/HA) composites

The aim of this study is to investigate the influence of hydroxyapatite’s (HA) particle size, shape, and variation of HA weight percentage on the rheological behaviour of polycaprolactone/hydroxyapatite (PCL/HA) composite. The composite was produced by melt blending process using a single screw extruder assisted with an ultrasonic wave with varied HA weight content (0 wt.%, 10 wt.%, 20 wt.%, 30 wt.% and 40 wt.%). Two types of HA were used, which are needle shape (HAN) and irregular shape (HAS). The rheological behaviour of the PCL/HA composite was investigated through the melt flow index (MFI) test at a varied temperature of 100, 110, and 120 °C. The result indicated that an increase of HA content decreases the MFI values of the PCL/HA composite. At similar content of HA, PCL/HAN composite has higher activation energy with lower MFI values compared to PCL/HAS composite. In conclusion, this study concluded that the particle size, shape, and weight percentage of HA significantly affect the rheological behaviour of PCL/HA composites.