The "two-way" shape memory response of semicrystalline networks was studied on poly(epsilon-caprolactone)-based systems, crosslinked by thermal curing of methacrylic end-capped linear chains. By changing the methacrylation degree of the precursors, it was possible to vary the network density over one order of magnitude, without any remarkable change in their transition temperatures and crystallinity content. When subjected to a constant stress and to a cooling-heating cycle from above T-m to below T-c, the materials display reversible two-way shape memory capabilities, consisting in a cyclic elongation-contraction effect, which involves significant variations of strain. Two different cooling induced elongational processes are evidenced, one due to entropy elasticity and the other to a crystallization driven effect. The amount of elongation that may be achieved depends on the network density and on the applied stress, and it is maximized for systems with a crosslink density that allows to exploit both the entropy-and the crystallization-induced effect.
Evaluation of the shape memory performances of poly(ε-caprolactone)-based tubular devices for potential biomedical applications / Stefano Pandini; Alberto Borboni; Ileana Bodini; David Vetturi; Danilo Cambiaghi; Katia Paderni; Massimo Messori; Maurizio Toselli; Theonis Riccò.. - STAMPA. - (2014), pp. 306-309. (Intervento presentato al convegno 7th International Conference on Times of Polymers and Composites (TOP) tenutosi a Ischia, ITALY nel JUN 22-26, 2014) [10.1063/1.4876839].
Evaluation of the shape memory performances of poly(ε-caprolactone)-based tubular devices for potential biomedical applications
TOSELLI, MAURIZIO;
2014
Abstract
The "two-way" shape memory response of semicrystalline networks was studied on poly(epsilon-caprolactone)-based systems, crosslinked by thermal curing of methacrylic end-capped linear chains. By changing the methacrylation degree of the precursors, it was possible to vary the network density over one order of magnitude, without any remarkable change in their transition temperatures and crystallinity content. When subjected to a constant stress and to a cooling-heating cycle from above T-m to below T-c, the materials display reversible two-way shape memory capabilities, consisting in a cyclic elongation-contraction effect, which involves significant variations of strain. Two different cooling induced elongational processes are evidenced, one due to entropy elasticity and the other to a crystallization driven effect. The amount of elongation that may be achieved depends on the network density and on the applied stress, and it is maximized for systems with a crosslink density that allows to exploit both the entropy-and the crystallization-induced effect.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.