Manufacture of macroporous β-tricalcium phosphate bioceramics

Abstract

β-Tricalcium phosphate (β-TCP) macroporous ceramics were produced by a new manufacturing procedure. An organic skeleton constituted of polymethylmethacrylate balls (PMMA) is carried by a chemical forming treatment. This treatment consists to establish a connection between PMMA balls by a chemical superficial dissolution of the individual beads. This reaction is accompanied of significant shrinkage of the organic skeleton which is correlated with the interconnection size between beads. An empirical relation and a geometrical model, based on a theoretical arrangement of spheres of uniform sizes, were developed to determine the necessary shrinkage of the organic skeleton to obtain a desired interconnection size. PMMA skeleton is impregnated by using an aqueous suspension of β-TCP, after drying, the ceramic/polymeric composite undergoes the traditional steps of debinding and sintering to obtain finished material. This process allows a total control of the porous architecture of the part (sizes of pores and interconnections) and also to perform materials with very varied forms and dimensions with specific properties as a gradient of pore sizes or a gradient of the interconnection sizes.