Investigation of the mechanical, thermal and transport properties of NR/NBR blends: impact of organoclay content

In the present study efforts have been made to prepare organoclay nanocomposites of NR/NBR (natural rubber/nitrile rubber) blends using 0-4 wt% cloisite 93A by mixing on a laboratory type two-roll mill as per ASTM procedure. The organoclay-filled NR/NBR blends exhibited high tensile strength due to the formation of inter-phase crosslinks. The modulus values were also found increase in line with tensile strength. The clay platelets could be aligned in the direction of stretching of the rubber sample and the strong interfacial interaction between the NR and the NBR chains and the clay platelets could support local load transfer, resulting in enhanced modulus. The results of Scanning Electron Microscopy (SEM) fractographic analysis were in agreement with the mechanical test results and support the observed changes in the NR/NBR blend properties as the clay content increases. Transmission Electron Microscopy (TEM) images showed intercalated clay layers in both phases of the blend, indicating good compatibilization. Crosslink densities of the vulcanized samples exhibited an increase in the values on the increase in dosage of the nanoclay, supporting the fact that high specific surface area of the layered silicates enhanced reinforcement of the polymer matrix.