Poly(ε-caprolactone) reinforced with fibres of Poly(methyl methacrylate) loaded with multiwall carbon nanotubes or graphene nanoplatelets

Aligned electrospun fibres of Poly(methyl methacrylate) (PMMA), either neat, loaded with multiwall carbon nanotubes (MWCNTs) or with graphene nanoplatelets (GNPs) were used as reinforcement of a Poly(epsilon-caprolactone) (PCL) matrix. Previously to fibre formation, MWCNTs and GNPs were accurately disentangled and dispersed in N,N-Dimethylformamide (DMF) by means of sonication. In some cases sonicated GNPs were further dispersed by centrifugation. All electrospun fibres are uniform and well aligned, with a mean diameter ranging between 1-2 mu m. PCL films were produced by solvent casting. The composites were manufactured by means of film stacking technique, performed at 90 degrees C for 30 min under pressure in order to insure PCL melting and flowing and correct fibre impregnation. In all composites the PCL matrix revealed to be strongly adhered to the fibres. The insertion of PMMA reinforcement leads to an increase in yield stress of the PCL from 5.0 +/- 0.1 to 10.4 +/- 0.5 MPa. The addition of the carbon fillers produces a further slight improvement in the mechanical properties and the best results are obtained for the samples prepared starting from the centrifuged dispersion of GNPs (yield stress = 14.0 +/- 0.5 MPa). (c) 2012 Elsevier B.V. All rights reserved.