(BEING CONTINUED FROM 22/01/14)
V. EXPERIMENTAL TECHNIQUE
The work has focused on the preparation,dispersion, adhesion and orientation of nanofillers
into composite laminate for obtaining the required functionality. The target has been to optimize the two
technologies proposed for this integration (direct resin bulk doping and buckypaper manufacturing for
later resin infiltration) in order to obtain:
· An optimal and stable dispersion of nanofillers into the final laminate
· A suitable nanofiller/resin interfacial bonding
· Preservation of the integrity of nanoreinforcements during integration process.
As aforementioned, two approaches to integrate the nanomaterials in the composite structure have been
· Bulk doping strategy: Dispersion techniques such as three roll mill, high shear mechanical stirring,
etc. have been studied in order to obtain the best dispersion of nanofillers into the resin and good
interfacial bonding. Once the resin is doped,laminates have been manufactured by hand layup
and autoclave curing. With this approach the maximum nanofiller loading level is determined
mainly by the initial viscosity of the resin.
From the studies performed, it can be observed that the epoxy resin can be doped with high
percentage of W particles keeping manufacturability parameters (viscosity around 4000-5000cp). A maximum content of 0,5%
CNT and 30% W can be achieved when combining both fillers to dope the epoxy resin.
· Buckypaper (BP) strategy: The method for production of buckypapers has been based on a
multiple-step process that includes dispersion of CNTs/tugsten nanofillers in a solvent and
filtration processes; ultrasonication, mechanical stirring and the use of surfactants to obtain a
stable nanofiller suspension before filtering. The manufactured buckypaper have been integrated
into prepreg lay-up for later curing in autoclave.
Comparing with bulk doping approach, localized higher nanofiller content can be obtained with
Figure 7: Buckypaper: 6 % MWNT – 94% of Wparticles.
A high CNT loading can be obtained with BP.
These are porous materials; therefore, a good impregnation with epoxy resin is assured. On the
other hand, high contents of CNT in combination of W nanoparticles can be obtained (50 %
CNT+50 % W). Thanks to the CNT network Wnanoparticles decantation is not produced
In both approaches, doped laminate coupons with different percentage of nanofillers have been
manufactured with the following stacking sequence [0, +45, 90, -45,Central layer (doped resin or BP),-45,
90, 45, 0] to be used in subsequent testing activities.
In Figure 8 and in Figure 9, a detail of the manufactured laminates is presented. Reference
coupons without any nanofiller inclusions have also been fabricated for reference purposes.
Figure 8: Doped resin. TEC 2: 88%W.
Figure 9: Buckypaper 6%CNT/94%W.
In Table 2 the samples manufactured are detailed:
Table 2: Manufactured samples.
G. Atxaga1TECNALIA, Spain, email@example.com
J. Marcos2, M. Jurado3, A. Carapelle4, R. Orava5
1 TECNALIA. Transport Unit, Spain, firstname.lastname@example.org
2 TECNALIA. Transport Unit, Spain, email@example.com
3 TECNALIA. Transport Unit, Spain, firstname.lastname@example.org
4 CSL, Belgium, email@example.com
5 Sensor Center, Finland, firstname.lastname@example.org
(TO BE CONTINUED)