The influence of different cellulose ethers on both the handling and mechanical properties of calcium phosphate cements for bone substitution

The influence of cellulose ether additives (CEAs) on the performance of final calcium phosphate cement (CPC) products is thoroughly investigated. Four CEAs were added into the liquid phase of apatitic CPCs based on the hydrolysis of alpha-tricalcium phosphate, to investigate the influence of both molecular weight and degree of substitution on the CPCs' properties, including handling (e.g. injectability, cohesion, washout resistance and setting time), microstructure (e.g. porosity and micromorphology) and mechanical properties (e.g. fracture toughness and compressive strength). The results showed that even a small amount of CEAs modified most of these CPCs' features, depending on the structural parameters of the CEAs. The CEAs dramatically improved the injectability, cohesion and washout resistance of the pastes, prolonged the final setting time and increased the porosity of CPCs. Moreover, the CEAs had an evident toughening effect on CPCs, and this effect become more significant with increasing molecular weight and mass fraction of CEAs, inducing a significant tolerance to damage. Overall, the molecular weight of CEAs played a major role compared to their degree of substitution in CPCs' performances. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.