EFFECTS OF FILLER HYBRIDIZATION ON THE MECHANICAL PROPERTIES OF NR/SBR/EPDM RUBBER BLENDS

Hybridization of active fillers is one of the techniques utilized to enhance rubber properties. This study highlights the effects of filler hybridization on the mechanical properties of an industrial applied natural rubber/styrene butadiene rubber/ethylene propylene diene terpolymer (NR/SBR/EPDM) Rubber Mat compound reinforced by non-black fillers. Initially, three different rubber compounds were prepared; i) calcium carbonate (CaCO3)-filled NR [CaCO3NR] as reference sample, ii) precipitated silica (PSi)-filled NR/SBR/EPDM [PSiBR], and iii) calcined clay (ClCy)-filled NR/SBR/EPDM [ClCyBR]. From these compounds, composites of NR/SBR/EPDM were prepared. The ratio of PSi:ClCy was varied to study the effects of filler hybridization. CaCO3 was added for cost advantage industrially and its level was fixed. It was found that inclusions of ClCy and PSi individually and their hybridizations show higher tensile and tear strengths than the reference sample. Particularly, the largest improvement was found with the amount of ClCy which is higher than PSi. A ratio of PSi:ClCy in this particular range (1:2 to 2:3), seems to provide the optimum packing factor for good interaction between the fillers. SEM analysis suggests that better dispersion and packing of fillers due to size and shape of hybrid fillers play an important role in improving the composite properties

Characterization on Thermal And Mechanical Properties of Non-Covalent Polyethyleneimine Wrapped on Graphene Nanoplatelets Within NR/EPDM Rubber Blend Nanocomposites

This study focused on the characterization of Natural Rubber (NR)/Ethylene Propylene Diene Monomer (EPDM) filled Graphene Nanoplatelets (GNPs) nanocomposites. The effects of GNPs non-covalent surface treatment using polyethyleneimine (PEI) and different loading of filler addition (0.25-5.00 wt. %) to cure characteristics, thermo-mechanical and thermal degradation properties of produced NR/EPDM rubber blends nanocomposites were analyzed and inter-correlated with their fracture morphologies. The surface treatment of GNPs was found to enhance the fillermatrices interaction in the NR/EPDM blend nanocomposites compared with unfilled and untreated GNPs filled NR/EPDM systems at similar loadings. The nanocomposites with 3.00 wt. % of PEI-treated GNPs possessed outstanding mechanical properties compared with unfilled NR/EPDM blends and filled nanocomposites without treatment (tensile strength of 27.78 MPa, 19.65 MPa and 23.34 MPa; respectively). The results were supported with thermal and dynamic analyses. Highly homogeneous dispersion of GNPs nanofillers and the presence of strong interfacial interaction between the matrix and reinforcement nanofiller resulted in an excellent thermal-mechanical properties of nanocomposites filled with 3.00 wt. % PEI treated GNPs. Obvious fractured morphological changes due to the noncovalent treatment provided hints on the role of GNPs treatment in improving the NR/EPDM blends mechanical and thermal properties