[en] A combination of solid-state proton Wide-line Nuclear Magnetic Resonance (NMR) relaxometry and synchrotron Small-angle (SAXS) and Wide-angle (WAXD) X-ray scattering was used to elucidate the microphase morphology of shape memory thermoplastic multi-block polyurethanes based on poly(3-caprolactone), as switching segment and polyurethane based permanent or hard segments (HS). The polyurethanes are produced from the condensation of 1,4-butanediol (BDO) with hexamethylenediisocyanate (HDI). The morphology – induced by the hard-segment crystallization – converts from dispersed randomly placed hard-segment domains into progressively more periodic, but interconnected HS nanophases with increasing HS content. Irrespective of the actual morphology, the SAXS data could be described satisfactorily by using a clipped Gaussian random field (GRF) model. The NMR data demonstrate that the HS domain fraction corresponds to the chemical feed, pointing at a complete phase separation. The material mechanical behavior during repeated deformation cycles can be explained on morphological grounds and involves a spatially heterogeneous
plastic deformation of the hard domains.
Disciplines :
Physics Chemistry
Author, co-author :
D'Hollander, Stijn; Universiteit Gent - Ugent
Gommes, Cédric ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Génie catalytique
Mens, Raoul; Universiteit Hasselt
Adriaensens, Peter
Goderis, Bart; Katholieke Universiteit Leuven - KUL
Du Prez, Filip
Language :
English
Title :
Modeling the morphology and mechanical behavior of shape memory polyurethanes based on solid-state NMR and synchrotron SAXS/WAXD
Publication date :
2010
Journal title :
Journal of Materials Chemistry
ISSN :
0959-9428
eISSN :
1364-5501
Publisher :
Royal Society of Chemistry, Cambridge, United Kingdom
Volume :
20
Pages :
3475–3486
Peer reviewed :
Peer Reviewed verified by ORBi
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE]