https://doi.org/10.1140/epje/i2011-11009-8
Free-standing urethane/urea elastomer films undoped and doped with ferro-nano-particles
1
Instituto de Fısica, Universidade de São Paulo, caixa postal 66318, 05314-970, São Paulo, Brazil
2
Faculdade de Ciências e Tecnologia e CENIMAT/I3N, Universidade Nova de Lisboa, Quinta da Torre, P-2829-519, Caparica, Portugal
3
Centro de Fısica da Matéria Condensada, Av. Prof. Gama Pinto 2, 1649-003, Lisboa, Portugal
4
Departamento de Fısica, Instituto Superior Técnico, TU Lisbon, Av. Rovisco Pais 1, 1049-001, Lisboa, Portugal
5
DEEC AC-Energia, Instituto Superior Técnico, TU Lisbon, Av. Rovisco Pais 1, 1049-001, Lisboa, Portugal
Received:
16
August
2010
Revised:
19
October
2010
Accepted:
22
December
2010
Published online:
24
January
2011
We report on an experimental study of the structures presented by urethane/urea elastomeric films without and with ferromagnetic nanoparticles incorporated. The study is made by using the X-ray diffraction, nuclear magnetic resonance (NMR), optical, atomic and magnetic force (MFM) microscopy techniques, and mechanical assays. The structure of the elastomeric matrix is characterized by a distance of 0.46nm between neighboring molecular segments, almost independent on the stretching applied. The shear casting performed in order to obtain the elastomeric films tends to orient the molecules parallel to the flow direction thus introducing anisotropy in the molecular network which is reflected on the values obtained for the orientational order parameter and its increase for the stretched films. In the case of nanoparticles-doped samples, the structure remains nearly unchanged although the local order parameter is clearly larger for the undoped films. NMR experiments evidence modifications in the molecular network local ordering. Micrometer size clusters were observed by MFM for even small concentration of magnetic particles.
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2011