The effect of graphene and nanoclay on properties of nitrile rubber/polyvinyl chloride blend with a potential approach in shock and vibration damping applications

In quest of lightweight elastomeric vibration damping material, two types of nanocomposites were made with a 50/50 blend of nitrile rubber/polyvinyl chloride (NBR/PVC) reinforced by 2, 5, 10, and 20 phr organically modified nanoclay (OMMT) and graphene nanoplatelets (GRN). The mixing was done by a conventional two-roll mill. Morphology of fractured surfaces revealed uniform mixing of OMMT and GRN, but agglomeration was observed beyond 5 phr, more for OMMT. X-ray diffraction showed intercalation/exfoliation in both types of nanocomposites. GRN improved the hardness monotonically up to 1.25 times and tensile modulus about 3 times, while OMMT improved tensile strength by 1.3 times with a 6-7% increase in elongation-at-break. The tensile modulus decreased with increasing strain for both composites. The improvement in tensile modulus relative to unfilled blend was uniform for 10, 20, and 30% strain for both types of nanocomposites and followed second-order polynomial fit, with different coefficients for GRN and OMMT. The improvement by GRN was continuous, while for OMMT, there is a theoretical maximum at 11% volume. The compressive modulus increased non-linearly with strain, up to 2.5 times for GRN loading and to about 1.5 times with OMMT loading compared to the unfilled NBR/PVC blend. The compressive modulus at 20% strain for both types of composites was in agreement with the theoretical model by Rocard. The ratio of compressive to tensile moduli vs. filler content was constant for OMMT filled composites and decreased continuously with GRN content at both 10% and 20% strain levels. [GRAPHICS] .