Durability of polymer-ceramics composite implants determined in creep tests

The polymer base composites are considered as one of the most promising groups of materials in medicine. Implants made of these materials have mechanical properties similar to natural tissues, show good biological compatibility, and also can be formed into various shapes. In living organism longterm working implants are subjected to mechanical stresses as well as aggressive body liquids. While aging, they can change their mechanical and biological properties. Investigations presented in this study show the influence of conditions simulating human body on the mechanical properties of two types of polymer composites such as: polysulphone–hydroxyapatite (PSU + HAP) and poly(lactide-co-glicolide)–hydroxyapatite (PGLA + HAP). Durability of investigated materials was estimated on the basis creep tests. The analysis of biological durability has been also performed, including the effects of modifying additives on the performance of examined composites. The biostable materials may be used as long-term implants with the stress level between 10% and 20% of initial strength. For resorbable polymers and their composites the time of resorption is a very important factor, and it depends on polymer’s microstructure and the presence of modifying phases.