Surface Structure and Associated Tribological Properties of NR/TOR Blends

Composition and structure of the surface layer of natural rubber (NR)/ polyoctenamer (TOR) blends were studied. Fourier transformed attenuated total reflection infrared spectroscopy (FT-ATR IR) revealed the surface enrichment with a macrocyclic phase, what was interpreted as the surface segregation of TOR occurred in the blends. The effect is especially pronounced for small amounts of the macrocyclic polymer blended with the rubber, not exceeding 25 phr. The surface layer is probably composed of low molecular weight polymer fraction, facilitating better temperature stabilisation, described previously, together with low friction of the material. Nanoindentation of the surface did not reveal any hardening of the blend, that could be subscribed to a crystalline phase formation.