Developing tricalcium phosphate/polyhydroxybutyrate composite as a new biodegradable material for clinical applications

Abstract

Two biodegradable materials, namely, tricalcium phosphate (TCP) and polyhydroxybutyrate (PHB), were used to produce a new composite material for tissue replacement/regeneration. Commercially available TCP and PHB were used, with both materials being in the form of fine powders. They were characterised prior to composite production. TCP/PHB composite containing up to 30vol% of TCP was produced. Manufacture of the composite consisted of compounding, milling, drying and compression moulding. During the manufacturing process, the temperature and time for maintaining PHB in the molten state were carefully controlled as PHB is very heat-sensitive. Thermogravimetric analysis (TGA) of the composite indicated that intended compositions for the composite had been achieved. Examinations using a scanning electron microscope (SEM) revealed that TCP particles were well distributed in compounded and compression moulded materials. Differential scanning calorimetry (DSC) analysis showed that an increase in the TCP content resulted in decreases in both the melting temperature and the crystallinity of PHB. An ascending trend of microhardness was observed for TCP/PHB with an increase in the TCP volume percentage. Dynamic mechanical analysis (DMA) showed that the storage modulus increased from 2.76GPa for the unfilled PHB to 4.80GPa for the composite containing 20vol% of TCP.