%0 journal article
%@ 0391-3988
%A Behl, M.,Zotzmann, J.,Lendlein, A.

%D 2011
%J The International Journal of Artificial Organs
%N 2
%P 231-237 
%R doi:10.5301/IJAO.2011.6424
%T One-way and reversible dual-shape effect of polymer networks based on polypentadecalactone segments
%U https://doi.org/10.5301/IJAO.2011.6424
2 
%X A series of degradable polymer networks containing poly(ω-pentadecalactone) (PPD) switching segments showing a thermally-induced shape-memory effect were synthesized by co-condensation of,PPD-macrotriols or -tetrols with an aliphatic diisocyanate. Thermal and mechanical properties at different,temperatures were explored for polymer networks as a function of crosslink density by varying the,polymer chain segment length or the netpoint functionality. All polymer networks exhibited excellent,shape-memory properties with shape recovery rates Rr between 99% and 100% determined in the 5th,cycle under stress-free conditions. Furthermore, the polymer networks were capable of a reversible,dual-shape effect based on crystallization induced elongation (CIE) and melting-induced contraction,(MIC) in cyclic, thermomechanical experiments under constant stress. In these tests, the polymer networks,were capable of a shape-change of 130% elongation. The associated temperatures at which,CIE or MIC occurred (TCIE and TMIC ) were shown to be a function of the applied stress. By an increase,of stress of 1.6 MPa, TCIE could be increased by 10 K.