%0 conference object
%@ 
%A Raza, S.H.,Klusemann, B.

%D 2017
%J Book of Abstracts, 88th GAMM Annual Meeting 2017
%N 
%P 246 

%T Modeling of PLLA near glass transition temperature
%U 
 
%X The treatment for Coronary Heart Diseases - caused by the deposition of plaque on,arterial walls - which has been the deployment of metal stent in the blocked artery, poses,serious complications in the form of accumulation of blood clots due to the permanent,and rigid nature of metals. Meanwhile, Bioresorbable Vascular Scaffolds (BVSs) - made,up of poly l-lactide (PLLA) - are transient implants offering support to artery for 6-9,months and leaving no trace behind once dissolved after 2 years. PLLA, however, has,lower strength compared to metals and thus requires a higher thickness to make it useful,for transplants. Thermal annealing, which can alter the microstructure of PLLA to,make it thinner and stronger, is a good solution for this problem. In order to implement,thermal annealing, experimentation and simulations are required to study the behavior,of the microstructure during the process. In general, its behavior below glass transition,temperature and at short time-scale is glassy, while above glass transition temperature,and at long time scale is rubbery. With constitutive models available for other polymers,,such as polyethylene terephthalate (PET) - not only a significant polymer due to its,extensive industrial use but also a polymer that is temperature and strain-rate sensitive,- it is intended to develop a constitutive model for PLLA accordingly. In this regard,,the well-known Buckley model is implemented and extended. The model allows to study,the microstructural behaviour in PLLA at the temperatures of interest during thermal,annealing. Numerical results will be presented and compared for neat PLLA samples,for different strain rates and temperatures.