Synthesis and optimisation of ENR-CR-HNBR ternary elastomeric blend and composites with hybrid CB-silica fillers for hard rubber mountings

The present work focuses on developing a novel composite using a ternary elastomeric blend of epoxidised natural rubber/chloroprene rubber/hydrogenated nitrile-butadiene rubber(ENR/CR/HNBR- ECH) with hybrid fillers in different proportions, aiming to partially replace conventional filler of carbon black with silica as a cheaper alternative to suitable for hard rubber mountings. The work has two parts, the first part deals with determination of optimum blends of ternary elastomers namely ENR, CR and HNBR using a simplex centroid mixture design model. Seven samples are prepared and tested for their mechanical properties using which the optimum combination is determined by adopting Grey Relation Analysis (GRA)-based Response Surface Methodology (RSM) approach and benchmarked using GRA based Kriging-GA surrogate optimisation. The confirmed optimum combination of ECH blend is 33.34/53.33/13.33 phr. Hence in the second part, this optimum blend is taken as the base matrix for developing novel hybrid filled ECH composites by varying the filler contents of CB and silica. Thirteen composites are fabricated following a Face Centered Central Composite (CCF) design and tested for mechanical properties. The optimisation of hybrid filler content is carried out following the same numerical techniques used for optimum blend determination. The optimum filler combination obtained is verified experimentally. Furthermore, these experimental studies are supported with morphological and ATR spectroscopic studies.