A double centrifuged pre-vulcanized natural rubber latex (NR)
with high ammonia content and with total solid content of
56.87% (49.08% of natural rubber) was used. This latex was kindly
supplied by TECNILATEX S.A., Spain. This type of latex was chosen
because it is widely used at industrial level. Also, the use of latex
avoids the chewing process which can distort the elastomeric network
formed by addition of the fillers. Moreover, it allows obtaining
thin films with an adequate degree of curing after a simple
drying process.
The thermally reduced graphite oxide (TRGO) was produced inhouse
by rapid adiabatic expansion of graphite oxide at 1000 C
under inert atmosphere [19]. Graphite oxide was synthesized from
natural graphite by the method of Brodie [20]. A thorough characterization
of the material has been already reported [19]. SDS
(NaC12H25SO4) and Pluronic F 127 HO(C2H4O)a(C3H6O)b(C2H4O)a)H
(where a = 100 polyoxyethylene portion and b = 65 polyoxypropylene)
supplied from Sigma–Aldrich were used as received. The
molecular structural formulas of the surfactants are shown in
Fig. 1