Investigating the Effect of Curing Activators on the Cure Kinetics of Acrylonitrile–Butadiene Rubber Filled with Graphene Oxide and Reduced Graphene Oxides Nanocomposites

For the first time, acrylonitrile–butadiene rubber (NBR)–graphene oxide (GO) and reduced graphene oxide (rGO) composites were prepared without cure activators: zinc oxide/stearic acid (ZnO/SA) and studied. The vulcanization characteristics of the compounds were systematically studied at 160–190°C, with the aid of rheometer and differential scanning calorimetry (DSC) techniques. NBR revealed rapid curing time (t90) with greater cure rate index compared with NBR–GO/rGO composites for the rheometer measurement. This results were in correspondence with the activation energies Ea (kJ/mol) calculated by Ozawa and Kissinger models of vulcanization kinetics. NBR–rGO obtained reduced t90 and Ea (kJ/mol) than NBR–GO, perhaps due to lower oxygenated groups: epoxide (–C–O–C–), carboxyl (–O–C=O), and hydroxyl (–OH) present. Although, the composites delayed in curing, they significantly recorded high tensile properties with high reinforcing factors than NBR. The order of increasing mechanical properties: NBR < NBR–rGO < NBR–GO followed the same order of increasing crosslinking density. In terms of tensile strength, NBR–GO-1 obtained 62.5% and 18.2% increment than NBR and NBR–rGO-1, respectively. The findings from this study indicate that the absence of ZnO/SA in rubber compounds may slow down curing of rubber–GO/rGO composites and lower networks compared with those containing activators ZnO/SA. However, optimization of ZnO/SA and with desired functional groups on graphene and derivative graphene sheets (GDS) including other proposed factors may enhance the curing speed of rubber–GDS based systems, without compromising their mechanical integrity for advanced applications

Coupling effect of waste automotive engine oil in the preparation of wood reinforced LDPE plastic composites for panels

We demonstrated the formulation of wood plastic composite (WPC) materials with flexural strength of 13.69 ± 0.09 MPa for applications in outdoor fencing using municipal waste precursors like low density polyethylene (LDPE) plastics (54.0 wt. %), sawn wood dust with particle size between 64 and 500 μm derived from variable hardwood species (36.0 wt. %) and used automotive engine oil (10 wt. %). The WPC panels were prepared by pre-compounding, extruding at a screw auger torque of 79.8 Nm and pressing through a rectangular mould of dimension 132 mm Ã 37 mm Ã 5 mm at temperature 150 °C. The efficacy of black waste oil, as a coupling agent, was demonstrated by the absence of voids and pull-outs on microscopic examination using scanning electron microscopy. No hazardous substances were exhaled during thermo-gravimetric mass spectrometry analysis. The percentage crystallinity of the LDPE in the as-prepared material determined by differential scanning calorimetry was 11.3%. Keywords: Wood plastic composites, Low density polyethylene, Wood dust, Physical, Thermal and mechanical propertie