Compatibilization of novel GO-XNBR-g-GMAC/XNBR/XSBR nanocomposites: the relationship between structure and properties

The current research aimed to investigate the different aspects of novel nanocomposites based on carboxylated acrylonitrile butadiene rubber (XNBR), carboxylated styrene butadiene rubber (XSBR), graphene oxide (GO), and glycidyl methacrylate-grafted XNBR compatibilizer (XNBR-g-GMAC) blend. For this purpose, the novel nanocomposites of GO-XNBR-g-GMAC/XNBR/XSBR with different XNBR, XSBR, and GO composition and with and without XNBR-g-GMAC were synthesized. The related characteristics including curing properties, swelling behavior, morphological, electrical and mechanical characteristics were studied through rheometry, swelling test, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) observation, electrical resistivity, mechanical test, dynamic mechanical thermal analysis (DMTA), etc. Results of rheometric tests revealed that the addition of XNBR-g-GMAC and increasing GO content reduces the scorch time (t5) and optimum cure time (t90) and increases the crosslink density (CLD). So that the addition of 5 phr of compatibilizer and 1 phr of GO to the XNBR75/XSBR25 blend reduced the t5 and t90 by 29% and 34%, respectively. TEM micrograph confirms the GO dispersion in rubber matrix and SEM observation shows that incorporation of XNBR-g-GMAC and GO reduces dispersed-phase droplet size due to the improved compatibility of XNBR and XSBR. According to the DMTA result, all the samples except XNBR/XSBR (without XNBR-g-GMAC) show one glass transition temperature (Tg) which means XNBR-g-GMAC successfully enhanced the compatibility of XNBR/XSBR. The mechanical properties of samples showed that by the increase of GO concentration tensile strength, elongation at break, modulus, fatigue life, and hardness increased. Testing surface temperature changes in constant voltage (75 V) showed that the addition of 0.3 phr GO showed the best result and the further increase of GO up to the value of 1 phr revealed the opposite result and caused a decrease of about 54%. The results of practical tests also confirm the theories.