Fabrication and Characteristics of Hydroxyapatite Reinforced Polypropylene as a Bone Analogue Biomaterial

Composite biomaterials, which consist of a polymer matrix and a particulate bioactive phase and are hence analogous to bone microstructure, have been developed for human hard tissue substitution. In this investigation, a manufacturing route employing injection moulding was established for producing bone analogue biomaterials. Using this manufacturing technology, a potential bone replacement material, hydroxyapatite (HA) reinforced polypropylene (PP) composite (HA/PP), was made, with the HA volume percentage being up to 25%. The characteristics of the HA/PP composite were studied using various techniques including scanning electron microscopy (SEM), differential scanning calorimetry (DSC), tensile testing, microhardness testing, and dynamic mechanical analysis (DMA). It was demonstrated that with the use of the established manufacturing route, HA particles were well dispersed and homogeneously distributed in the PP matrix. Properties of the composite were affected by the amount of HA incorporated in the composite. The melting temperature and crystallisation temperature of the composite were slightly affected by the addition of HA particles, and the crystallinity of the PP matrix polymer was decreased with an increase in HA content. Young’s modulus, microhardness, and storage modulus increased when the HA volume percentage was increased from 10 to 25%, with corresponding decreases in tensile strength, elongation at fracture and loss tangent. 2007 Wiley Periodicals, Inc. J Appl Polym Sci 106: 2780–2790, 2007