In this work we study the mechanical properties and failure mechanism of nano-composites made of graphene oxide sheets embedded in polymeric systems, namely films and electro-spun nanofibers. In this last system, contrary to conventional bulk composites, the size of the nano-reinforcement (GO sheets) is comparable to the size of the nanofibers to be reinforced (≈ 200 nm). As an ideal polymeric matrix we use gelatin. We demonstrate that the high chemical affinity of the two materials hinders the renaturation of gelatin into collagen and causes a nearly ideal mixing in the GO-gelatin composite. Adding just 1% of GO (wt of GO with respect to gelatin ) we obtain an increase of Young’s modulus >50% and an increase of fracture stress >60%. We use numerical simulations to study the failure mechanism of the fibers. Calculations agree very well with experimental data and show that, even if cracks start at GO sheet edges due to stress concentrations, crack propagation is hindered by the nonlinear behaviour of the matrix. As an additional advantage, the presence of the GO sheets in continuous gelatin films improves the material stability to phosphate buffer solutions from 2 days to 2 weeks, making it a better material than gelatin for applications in biological environments
Structural reinforcement and failure analysis in composite nanofibers of graphene oxide and gelatin / Panzavolta, S.; Bracci, B.; Gualandi, C.; Focarete, M. L.; Treossi, E.; Kouroupis-Agalou, K.; Rubini, K.; Bosia, F.; Brely, L.; Pugno, N. M.; Palermo, V.; Bigi, A.. - In: CARBON. - ISSN 0008-6223. - 78(2014), pp. 566-577.
|Titolo:||Structural reinforcement and failure analysis in composite nanofibers of graphene oxide and gelatin|
|Data di pubblicazione:||2014|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.carbon.2014.07.040|
|Appare nelle tipologie:||1.1 Articolo in rivista|