Tensile fractured surface of various filler-filled NR vulcanizates
are illustrated in Fig. 4. These SEM micrographs
revealed that the fractured surface of filler-filled NR vulcanizates
become rougher compared to the gum vulcanizates
due to better reinforcement effects of rubber-filler
interfacial interaction. The 1 phr OPA-filled NR vulcanizates
(Fig. 4b) showed a deeper, more tearing line and a coarser
surface that is similar to the 50 phr carbon black-filled
vulcanizates (Fig. 4d). This phenomenon agreed with the
tensile values reported before whereby, greater force was
required to fracture the samples..