Nanocomposites containing natural rubber (NR) as matrix, epoxidized natural rubber (ENR) as compatibilizer and
organophilic layered clay (organoclay) as filler were produced in an internal mixer and cured using a conventional sulphuric
system. The effects of ENR with 25 (ENR 25) and 50 mol% epoxidation (ENR 50), respectively, were compared
at 5 and 10 parts per hundred rubber (phr) concentrations. The organoclay content was fixed at 2 phr. Cure characteristics,
clay dispersion, (thermo)mechanical properties of the nanocomposites were determined and discussed. Incorporation
of ENR and organoclay strongly affected the parameters which could be derived from Monsanto MDR
measurements. Faster cure and increased crosslink density were attributed to changes in the activation/crosslinking
pathway which was, however, not studied in detail. The organoclay was mostly intercalated according to X-ray diffraction
(XRD) and transmission electron microscopic (TEM) results. The best clay dispersion was achieved by adding
ENR 50. This was reflected in the stiffness of the nanocomposites derived from both dynamic mechanical thermal analysis
(DMTA) and tensile tests. The tensile and tear strengths of the ENR 50 containing nanocomposites were also superior
to the ENR 25 compatibilized and uncompatibilized stocks.
2004 Elsevier Ltd. All rights reserved.