Poly(e-caprolactone) reinforced with fibres of Poly(methyl methacrylate) loaded with multiwall carbon nanotubes or graphene nanoplatelets F.R. Lamastra a,⇑ , D. Puglia c , M. Monti c , A. Vella b , L. Peponi d , J.M. Kenny c,d , F. Nanni a,b a Italian Interuniversity Consortium on Materials Science and Technology (INSTM), Research Unit Roma Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy b Department of Industrial Engineering, University of Rome ‘‘Tor Vergata’’, Via del Politecnico 1, 00133 Rome, Italy c Civil and Environmental Engineering Department, University of Perugia, Strada di Pentima 4, 05100 Terni, Italy d Institute of Polymer Science and Technology – CSIC, Juan de la Cierva 3, 28006 Madrid, Spain highlights " Electrospun fibres of PMMA loaded with MWCNT or with GNP were used to reinforce PCL. " For the first time electrospun mats with C fillers were employed in composite manufacturing. " The morphology, the thermal and mechanical properties of composites were investigated. " All composites showed enhanced mechanical properties with respect to neat PCL. article info Article history: Received 22 December 2011 Received in revised form 10 April 2012 Accepted 24 April 2012 Available online 1 May 2012 Keywords: Poly(methyl methacrylate) Poly(e-caprolactone) Multiwall carbon nanotubes Graphene nanoplatelets Electrospinning Composites abstract Aligned electrospun fibres of Poly(methyl methacrylate) (PMMA), either neat, loaded with multiwall car- bon nanotubes (MWCNTs) or with graphene nanoplatelets (GNPs) were used as reinforcement of a Poly(e-caprolactone) (PCL) matrix. Previously to fibre formation, MWCNTs and GNPs were accurately dis- entangled and dispersed in N,N-Dimethylformamide (DMF) by means of sonication. In some cases soni- cated GNPs were further dispersed by centrifugation. All electrospun fibres are uniform and well aligned, with a mean diameter ranging between 1–2 lm. PCL films were produced by solvent casting. The com- posites were manufactured by means of film stacking technique, performed at 90 °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). Ó 2012 Elsevier B.V. All rights reserved. 1. Introduction Electrospinning is an extremely flexible, low cost and easily industrial exploiting process to fabricate continuous, randomly ori- ented or uniaxially aligned fibres from a huge range of materials [1,2]. The electrospun fibres have very thin diameters, ranging from few tens of nanometres up to few microns, depending on spinning solution properties (i.e. viscosity, surface tension, conduc- tivity), processing parameters (i.e. needle-target distance, flow rate, applied voltage) and ambient conditions (i.e. humidity, type of atmosphere). Due to the very high surface to volume ratio typ- ical of electrospun fibres, the interaction with a matrix (leading to a high strengthening efficiency) is expected to be significantly enhanced, and therefore electrospun mats have been recently proposed as reinforcement of polymers as an alternative to con- ventional fibres [3]. Up to now, despite this undoubted benefit, only few attempts were made to fabricate nanocomposites with electrospun fibres as reinforcing element [4–7], that, however, con- firmed the possibility to achieve very interesting mechanical results. More recently, several research groups have proposed and suc- cessfully succeeded the incorporation of a nanoscale filler (as car- bon nanotubes (CNTs) [8], TiO 2 [9], SiO 2 [10], montmorillonite [11], b-tricalcium phosphate [12], Al 2 O 3 and ZrO 2 [13], to cite a few) into the fibres, with the aim to enhance their mechanical prop- erties. The further step, concerning the use of such nanofiller loaded electrospun fibres as reinforcement of a polymeric matrix, has not been investigated yet. To plug this gap and as a development of our previous work [7], in this research, MWCNT and GNP loaded aligned PMMA fibres were produced by electrospinning and used as reinforcement of PCL matrix. PMMA was chosen either due to 1385-8947/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.cej.2012.04.078 ⇑ Corresponding author. Tel.: +39 06 72594496; fax: +39 06 72594328. E-mail address: lamastra@scienze.uniroma2.it (F.R. Lamastra). Chemical Engineering Journal 195–196 (2012) 140–148 Contents lists available at SciVerse ScienceDirect Chemical Engineering Journal journal homepage: www.elsevier.com/locate/cej