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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.

This study is aimed to investigate the characteristics of the composite containing blended poly (ɛ-caprolactone) (PCL), hydroxyapatite (HA) and thermoplastic zein (TZ). Thermoplastic zein was developed by mixing zein with glycerol (GLY) and polyethylene glycol (PEG). The thermal characterization of mixed TZ and bio composite was characterized in order to investigate the characterization of PCL/TZ/HA composites. The bio composited was then moulded and produce porous structure via solid state supercritical carbon dioxide (scCO2) foaming process. The specimen was saturated with CO2 for 6 hours at 50˚C and saturation pressure of 20MPa at high depressurization rate. The morphology of porous specimen produced were characterized by scanning electron microscopy (SEM). The results indicated that after polymer saturation with CO2, high depressurization causes the formation of nucleated gas cells that give rise to pores within the foamed specimens. The blended bio composite with composition of PCL60/TZ20/HAp20 exhibit well interconnected porous structure compared to other bio composite prepared. The foaming effect produce foams with heterogeneous morphologies on bio composite material at relatively low temperature.

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