Browsing by Keyword "D. Rheology"
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Item Analysis of the conditions to manufacture a MWCNT buckypaper/benzoxazine nanocomposite(2012-02-28) Chapartegui, M.; Barcena, J.; Irastorza, X.; Elizetxea, C.; Fernandez, M.; Santamaria, A.; POLIMEROS; EXTREMAT; COMPOSITEA study of the requirements necessary to fabricate novel MWCNT buckypaper/benzoxazine nanocomposites, based on rheological results, is presented. Best conditions to infiltrate the resin, without any diluents, in the buckypaper are selected from viscosity data obtained under time-temperature cycles. Infiltration results are analyzed using SEM microphotographs. The nanocomposite is obtained after an adequate curing process of the benzoxazine impregnated buckypaper. The mechanical and electrical properties of the nanocomposite are investigated. The obtained electrical conductivity values are several orders of magnitude larger than the values reported for conventional CNT/polymer nanocomposites.Item Specific rheological and electrical features of carbon nanotube dispersions in an epoxy matrix(2010-05) Chapartegui, M.; Markaide, N.; Florez, S.; Elizetxea, C.; Fernandez, M.; Santamaría, A.; POLIMEROSThe rheological analysis of epoxy pre-polymer/MWCNT dispersions indicates that a physical network is formed. This is destroyed with an imposed shear, giving a viscoplastic and shear thinning behavior. Such destruction is not reflected in dynamic viscoelastic experiments, due to the very rapid recovery of the MWCNT network in the pre-polymer matrix. This responds to the observed lower electrical than rheological percolation threshold. Electrical conductivity results fulfill electron hopping/tunnelling mechanism, which implies a tube-tube distance close to 5. nm. However, rheological percolation requires nanotubes should touch each other, since no polymer chains are implied in the network.