NMR investigation of commercial carbon black filled vulcanized natural rubber exposed to petrodiesel/biodiesel mixtures

- NMR was used to understand the effect of biodiesel in commercial natural rubber.
- The biodiesel promotes the exudation of the filler with attached polymer chains.
- Biodiesel increases the number of defects and induces gaps in the remained network.
- Exudation of carbon black aggregates calls for fillers/rubbers with higher affinity.

The impact of biodiesel on the durability of the engine is a growing concern due to its corrosive characteristics. Nuclear magnetic resonance in the frequency (High Resolution NMR spectroscopy) and time (TD-NMR) domains were complementarily used to understand structural, dynamical and chemical modifications in commercial carbon black filled vulcanized natural rubber (CBVNR) due to contact with petroleum diesel/biodiesel mixtures. The results indicated that in biodiesel rich mixtures, besides the expected swelling effect, the interaction of fuel mixtures with CBVNR promotes the exudation of the filler together with attached polymer chains, which increases the number of defects and induces gaps in the remained network structure. The exudation of carbon black aggregates indicates that searching of fillers/elastomers combinations with higher affinity is an important parameter in the development of materials compatible with biodiesel.