Project Details
Projekt
Self-healing capacity of damage tolerant calcium phosphate biocements
Subject Area
Biomaterials
Solid State and Surface Chemistry, Material Synthesis
Solid State and Surface Chemistry, Material Synthesis
Term
from 2014 to 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 259165845
A major problem concerning the mechanical properties of mineral biocements is related to their inherent brittleness and absence of ductility, which prevents their use in load-bearing applications. Aim of this project is the fabrication of damage tolerant calcium phosphate cements. This will be realised by the integration of ductile polyethylene fibres into the cement matrix, which are surface modified by a reactive oxygen plasma treatment to allow chemical interactions with the cement matrix and to induce remineralization processes. Under mechanical load, the initiated cracks are bridged by the polymeric fibres and the crack growth energy is dissipated by friction processes between fibre, interface and matrix and the plastic deformation of the polymer. Following this, carboxylic acid groups at the fibre surface will induce remineralization due to their Ca2+ binding capacity leading to an intrinsic crack-healing. A further approach utilizes the extrinsic healing capacity achieved by the addition of phosphate containing microcapsules on the basis of polymethylmethacrylate. The beads are opened during initial cement cracking and the release of highly reactive acidic phosphates leads to the fast (< 1 min) formation of a secondary phosphate (brushite) or amorphous phosphates in the crack. Subsequently, these phosphates react with the inorganic components (HPO42-, Ca2+, CO32-) of a simulated body fluid (SBF) mimicking the extracellular physiological electrolyte and are transformed into apatite with a composition similar to the mineral phase of bone. The project will cover both material synthesis aspects (cement synthesis; surface modification of polymeric fibres by plasma treatment; the fabrication of phosphate loaded microcapsules), the mechano-chemical characterisation of the fibre-cement interface and the remineralisation behaviour and self-healing of cracks in simulated body fluid.
DFG Programme
Priority Programmes
