Theoretical and experimental analyses of rheological, compatibility and mechanical properties of PVMQ/XNBR-g GMA/XNBR/GO ternary hybrid nanocomposites

Effects of graphene oxide (GO) on various properties of rubber hybrid nanocomposites based on PVMQ/XNBR-g-GMA/XNBR (phenyl-vinyl-methyl-polysiloxane/carboxylated nitrile rubber-grafted maleic anhydride/XNBR) were identified. These nanocomposites were prepared with melt mixing method and fabricated by a laboratory two-roll mill. To evaluate the adhesion between the blend phases, i.e., PVMQ and XNBR, the results of microscopic and swelling tests were used simultaneously. The results showed that the adhesion of GO on PVMQ/XNBR rubber matrix was increased by the incorporation of XNBR-g-GMA as a compatibilizer. By increasing the amount of GO in the blend to 10 phr, the scorch time and curing time decreased by 24% and 26%, respectively, while the curing rate and maximum curing torque increased by 27% and 15%, respectively. Tear strength, hardness, and compression set of samples increased with increasing the GO content. The SEM images showed that the porosity of the prepared nanocomposites decreased from 17.34 to 4.84 µm for 5 phr GO. In the presence of a compatibilizer, the size of XNBR dispersed phase declined. This means that a stronger bond is formed between the blend phases. The results of TEM images also illustrated that the addition of compatibilizer to the PVMQ/XNBR rubber matrix resulted in excellent dispersion of GO nanoplatelets. To predict the mechanical and rheological properties, Mooney–Rivlin and Carreau–Yasuda models were applied, respectively. The parameters of these models were theoretically determined and compared with the experimental data, and a good agreement was observed.