MECHANICAL AND FRACTURE-BEHAVIOR EVALUATION OF COMMERCIAL ACRYLIC BONE CEMENTS

The deformation and fracture behaviour of some commercial acrylic bone cements have been investigated. Cements were characterized by gel per meation chromatography, dynamic mechanical analysis and scanning elect ron microscopy. The influence of liquid to powder ratio, curing temper ature, strain rate and non-reacted monomer was analysed for one radiol ucent cement. Results showed that the beta transition activation proce ss influences both deformation and fracture behaviour. Fracture surfac e stress whiteness revealed the presence of crazes as the main plastic deformation mechanism. Non-reacted monomer acted as a plasticizer lea ding to materials with lower yield strength, sigma(y), that induces cr ack tip blunting and improves toughness. It appears that the presence of radio-pacifier fillers also improves fracture toughness by promotin g interactions between the crack and the second phase dispersion.