Composites of carbon nanofibers and thermoplastic polyurethanes with shape-memory properties prepared by chaotic mixing


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Bibliographic Details
Authors: Jimenez, Guillermo A., Jana, Sadhan C.
Format: artículo
Publication Date:2009
Description:Composites of carbon nanofibers (CNFs), oxidized car bon nanofibers (ox-CNFs), and shape-memory thermo plastic polyurethane (TPU) were prepared in a chaotic mixer and their shape-memory properties evaluated. The polymer was synthesized from 4,40 -diphenylme thane diisocyanate, 1,4-butanediol chain extender, and semicrystalline poly(e-caprolactone) diol soft segments. The shape-memory action was triggered by both con ductive and resistive heating. It was found that soft segment crystallinity and mechanical reinforcement by nanofibers produced competing effects on shape memory properties. A large reduction in soft segment crystallinity in the presence of CNF and stronger me chanical reinforcement by well-dispersed ox-CNF determined the shape-memory properties of the re spective composites. It was found that the maximum shape recovery force, respectively, 3 and 4 MPa, was obtained in the cases of 5 and 1 wt% CNF and ox-CNF, respectively, compared with 1.8 MPa for unfilled TPU. The degree of soft segment and hard segment phase separation and thermal stability of the composites were analyzed. POLYM. ENG. SCI., 49:2020–2030, 2009. ª 2009 Society of Plastics Engineers
Country:Repositorio UNA
Institution:Universidad Nacional de Costa Rica
Repositorio:Repositorio UNA
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Access Level:acceso abierto