Research Article
John Duckworth, Mitsugu Tod
Abstract
The effect of fibre length in a cement/fibre composite biomaterial on cement/fibre integration, ultimate compressive strength and compressive elastic modulus was investigated. Dicalcium phosphate dihydrate/ poly(lactide-co-ε-caprolactone) 75:25 was the composite material investigated, at a 25%w/w ratio. A direct relationship between increased fibre length and increasing void volume in the material was determined using micro-CT imaging and Finite Element modelling, attributed to entanglement of the fibres causing poor cement/fibre integration. This in turn was used to explain a measured decrease in the compressive strength of composites with longer fibres, from 32±2 MPa to 24±3 MPa for composites containing 400±100 μm to 1280±350 μm length fibres respectively. It was also found that the compressive elastic modulus of all cement/fibre composites was far lower than that of blank cement alone, from 1.3±0.2 GPa to 270±70 MPa. However, no correlation could be drawn between compressive elastic modulus and void volume or fibre length, as any fibre presence at the set weight ratio had a similar effect.