Static and uniaxial characterization of polymer biomaterials

Mechanical properties play a critical role in the clinical outcome of many implantable devices, and must be, accordingly, considered an essential component of biocompatibility. As a consequence, an accurate and well-designed analysis of material load-bearing capabilities is essential. Due to their viscoelastic nature, mechanical characterization of polymeric biomaterials is fairly complicated, as their response to forces critically depends on time and temperature. For this reason, a reliable mechanical characterization of polymers necessarily requires dynamical analysis (see Chapter 9), but (quasi)-static testing can also provide many fundamental information on material capabilities to sustain loads. In this chapter, the methods for quasi-static mechanical testing of polymeric biomaterials are described. In the first part, the fundamental concepts required for the comprehension and interpretation of mechanical testing results are illustrated. In the second part, the more common methods and instruments for mechanical characterization of polymers are illustrated, together with applicative examples.