Poly (ε-caprolactone)/hydroxyapatite composites: Effects of particle size, molecular weight distribution and irradiation on interfacial interaction and properties

Hydroxyapatite reinforced poly(ε-caprolactone) composites with different particle sizes and molecular weight distributions were prepared using a simple melt-processing method. Some composites were modified by electron beam irradiation. Dynamic viscoelastic properties were investigated using dynamic mechanical thermal analysis (DMTA) and an advanced rheometric expansion system. The results showed that the composite with narrower molecular weight distribution and smaller particle sizes had better processing and mechanical properties. Correspondingly, its interfacial interaction determined from differential scanning calorimetry, together with DMTA, was also stronger. Irradiation seriously damaged the adhesive interaction between the two phases, as observed under a scanning electron microscope, thus deteriorating the properties.