Characterization of homogeneous and pseudocomposite homopolymers and copolymers for articular cartilage replacement

Semicrystalline swollen polymeric networks are prime candidates for biomedical applications. Purity, controlled structure, easy preparation, non-biodegradability and improved mechanical properties are some of their most important characteristics. New articular cartilage simulants in the form of hydrogels with surface hydroxyl groups have been developed and characterized. The mechanical properties and physical behavior of these materials are described by high elastic moduli, ultimate tensile strength and elongation at break, low tear propagation resistance and excellent friction properties. Crystallinities vary between 15% and 35% and the crystallites are stable within the range of practical applications. The hydrogels show no permeability to hyaluronic acid and can be grafted with cationic monomers or polymers to form boundary lubricant layers. Techniques have also been developed for the preparation of deformable pseudocomposites consisting of layers of swollen semicrystalline and amorphous polymer.