Constitutive modeling and mechanical behavior prediction of biodegradable polymers during degradation

• Type: Chapter or Part of a Book
• Date: 2015

Authors

André Vieira (Author) Other; Rui Miranda Guedes (Author) FEUP; Volnei Tita (Author) Other

Book

Title: Biodegradable Polymers. Volume 1: Advancement in Biodegradation Study and Applications

Pages: 31-75

ISBN: 978-1-63483-632-6

Indexing

Scopus - 0 Citations

Scientific classification

FOS: Engineering and technology > Mechanical engineering

CORDIS: Technological sciences > Engineering > Biomaterial engineering

Other information

Authenticus ID: P-00N-4C9

Abstract (EN): A large range of biodegradable polymers has been used to produce implantable medical devices, such as suture fibers, fixation screws and soft tissue engineering devices. Apart from biological compatibility, these devices should also be functional compatible and perform adequate mechanical temporary support during the healing process. The mechanical behavior of biodegradable polymers is known to be rate dependent and to exhibit hysteresis upon cyclic loading. On the other hand, ductility, toughness and strength of the material decay during hydrolytic degradation. Continuum based mechanical models can be used as dimensioning tools for biodegradable polymeric devices, since they enable to predict its mechanical behavior in a complex load and environment scenario, during the hydrolytic degradation process. The existing models can be divided into two categories: the time-dependent models and the time-independent models. Linear elastic or non-linear elastic models, such as elastoplastic or hyperelastic models, can simulate the time-independent response, which corresponds to the relaxed configuration and represent the relaxed state. However, these approaches neglect the time-dependent mechanical behavior. To consider time dependency, dissipative elements must be used in the model formulation. A revision of the three-dimensional constitutive models generally used for polymers is presented in this chapter. These models are based on the concept of networks, combining elastic, sliding and dissipative elements, in order to simulate the time-dependent mechanical behavior, although neglecting changes in the properties of the material during hydrolytic degradation process. Thus, some of these models were recently adapted to address the hydrolytic degradation process. A common method consists on becoming some of the material model parameters dependent on a scalar variable, which expresses the hydrolytic damage.Furthermore, the advantages and limitations of the models are discussed, based on the correlation between predictions and experimental results of a blend of polylactic acid and polycaprolactone (PLA-PCL), which include monotonic tensile tests at different strain rates and quasi-static cyclic unloading-reloading.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 44