Mechanical and electrical properties of natural rubber and nitrile rubber blends filled with multi-wall carbon nanotube: Effect of preparation methods

Carbon nanotube (CNT)/NR masterbatches prepared by predispersing and conventional methods were mixed with NBR for preparing CNT-filled 50/50 NR/NBR blends. The amount of CNT in the blends was varied from 0 to 6 phr. At a given CNT loading, hardness, modulus, tensile strength and tear strength of the blends containing the masterbatches prepared by the predispersing method were significantly higher than those prepared by the conventional method. This was simply due to the better CNT dispersion in the blends. Additionally, dynamic mechanical results showed that the maximum tan δ of the vulcanizates containing the masterbatches prepared by the predispersing method was lower than that of the corresponding conventional samples. This behaviour indicated the stronger reinforcing efficiency when the masterbatch prepared by the predispersing method was utilized. In addition, the volume resistivity of the P blends was lower than that of the corresponding C blend by about 2 orders of magnitude when only 2 phr of CNT was added. Moreover, thermal conductivity of the P blend having 4 phr of MWCNT was 1.7 times higher than that of the corresponding sample prepared by the conventional method.