عنوان مقاله [English]
Hypothesis: Various properties of NBR depend extremely on acrylonitrile (ACN) content of rubber formulation. One of the regular blends of NBR is NBR/PVC. Moreover, as it is widely known nanographene, due to its high specific surface area, is a performance material for producing polymer nanocomposites and for improving thermal and mechanical properties. To study the effect of nanographene on curing, tensile and stress relaxation properties of nanocomposites is interesting and important in practical terms and quality. The hypothesis of this research is to demonstrate the effect of temperature on the physico-mechanical of nanocomposites filled with various amounts of nanographene.
Methods: NBR/PVC/nanographene nanocomposites were prepared using NBR/PVC blends with a ratio of 70/30 and acrylonitrile butadiene rubber at acrylonitrile contents of 33% and 45%, incorporated with 0.5, 1.0 and 1.5 phr of nanographene by melt intercalation method using a two roll mill. PVC of 30 phr was mixed with the above compounding formulations in an internal mixer. The TEM images, tensile properties and RPA results (curing and stress relaxation behavior) were obtained and compared. The effect of temperature (25, 50, 75°C) on tensile properties was also studied.
Findings: Nanographene increased the maximum curing torque, scorch time and curing time. Samples containing higher ACN percentage, showed higher maximum curing torque, scorch time and optimum cure time. In the stress relaxation test, it was observed that the increase in the amount of nanographene increased the initial modulus and reduced the final modulus of the nanocomposites in the uncured and cured states. In formulations with high CAN content, the initial and final moduli showed higher values. By increasing the nanographene content and formulations with higher CAN content, higher elastic and viscous slopes were observed. The tensile properties of nanocomposites, including tensile strength, elongation and modulus were increased by higher amount of nanographene. In addition, the tensile properties of nanocomposites at three different temperatures of 25, 50 and 75°C were investigated and compared. With increasing nanographene concentration and rising temperature, samples showed a much lower reduction in tensile strength and Young's modulus than those in unfilled sample.