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Evaluation of fatigue behaviour of elastomeric biomedical polymers

Miroslawa El Fray 

Technical University of Szczecin, Polymer Institute, Pulaskiego 10, Szczecin 70-322, Poland


Polymeric materials are utilised in the manufacture of a high number of load-bearing structural components. Since many loads are cyclic in nature, the deformation under cyclic loads (fatigue) is of particular interest. Especially creep properties of elastomers are of great importance when materials are expected to remain structurally stable within long duration loading. Generally, two experimental strategies can be applied: one is fracture mechanical investigations of fatigue crack growth behaviour; the other is hysteresis measurements conducted for the evaluation of fatigue behaviour using engineering parameters, i. e. deformation, dynamic modulus, stored and lost energies, and damping. This second method is particularly valuable for evaluation of structural changes of soft materials under cycling loading. Hysteresis loops are induced by the viscoelastic material behaviour and the slope of the hysteresis loop is affected by the cyclic degradation. During the fatigue experiments the hysteresis loop is digitalized by a computer and from the slope of the hysteresis loop the stress, strain, stiffness and energy related parameters are determined.

Evaluation of fatigue behaviour of novel and the reference elastomeric biomaterials will be presented. Novel poly(aliphatic/aromatic-ester)s (PED) containing poly(butylene terephthalate) (PBT) hard segments and dimer fatty acid (DFA) soft segment are soft, rubbery thermoplastic elastomeric materials. The dynamic creep was investigated by monitoring the position of the hysteresis loop. Especially, the change of the strain-related material properties as a function of the hard/soft segments concentration will be presented. The fatigue properties (dynamic creep) were also investigated under simulated physiological conditions (simulated body fluid, SBF), and the influence of the testing temperature and environment will also be discussed.


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Presentation: oral at E-MRS Fall Meeting 2004, Symposium B, by Miroslawa El Fray
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-04-20 15:13
Revised:   2009-06-08 12:55