Effect of natural rubber/epoxidized natural rubber (90/10) on mechanical and thermal properties of linear low density polyethylene.

The effects of blending different amounts of (90/10) natural rubber/epoxidized natural rubber (NR/ENR-50) with metallocene linear low density polyethylene (mLLDPE) on the tensile strength, elongation at yield point, Young’s modulus, hardness and thermal properties were investigated. In this study, N, N-m-phenylenebismaleimide (HVA-2) was used as compatibilizer for the blends. The highest tensile strength was observed in the blend of 90/(9/1) mLLDPE/NR/ENR-50. With increasing mixed rubber content, the tensile modulus is found to decrease continuously, but interestingly the hardness and elongation at yield point is shown to increase. The crystallinity percentage of 10% rubber/mLLDPE was the lowest percentage. The maximum physical crosslinks occur in 90/(9/1) mLLDPE/NR/ENR-50 composite blend. The FTIR showed that the epoxy and double bond groups were found to be absent in all blends indicating thermal stability and compatibility of mLLDPE/rubber blends were improved by addition of 10 and 30% loading of rubber, in the presence of HVA-2 as compatibilizer

Experimental and Runge–Kutta Method Simulation to Investigate Corrosion Kinetics of Mild Steel in Sulfuric Acid Solutions

The mild steel is extensively used in different industrial applications and the biggest problem in the application of mild steel is corrosion. In this work, the reaction kinetics of mild steel with sulfuric acid at different concentrations and at different temperatures were studied in combination with the experimental data and theoretical approach using the Runge–Kutta method. The results revealed that the rate of reaction constant for temperatures in the range of 30–50°C was changed from 2618 to 2793 L3/mol3.h, respectively. The order of reaction of mild steel was 4th order in all temperature ranges. The enthalpy, entropy, and Gibbs free energy of mild steel reaction at a temperature of 298 K were estimated. The activation energy (E/R) of the reaction was 4.829 K. It was concluded that the sulfuric acid reaction with mild steel occurred easily and the inhibitors should be used in these systems

Pyrolysis, kinetic and kinetic model study of epoxidized natural rubber

Pyrolysis, kinetics properties and a kinetic model of epoxidized natural rubber (ENR-50) were studied in this work by differential scanning calorimeter (DSC) and thermogravimetry analysis (TGA/DTGA) tests. DSC results indicated that the ENR-50 rubber remained still, without degradation, until 354.65°C and ENR-50 degrades at temperatures ranging between 354.65 to 420°C at a constant heat rate (10°C/min). The degradation enthalpy was (-1241.8 J/g) and the remaining ash was 1.48% at 500°C. Degradation kinetics were studied according to Kissinger, Flynn-Wall-Ozawa, Friedman and Kissinger-Akahira-Sunose methods at different heating rates in nitrogen, at a flow rate of 20 ml/min. Activation energies and the pre-exponential factor were evaluated from the slope of Flynn-Wall-Ozawa, Friedman and Kissinger-Akahira-Sunose plots at conversions between 10 and 90%. The activation energy was also calculated by the Kissinger's method and it was equal to 41.735 kJ mol-1. Criado's method was employed to investigate the kinetic model, g(α;) of ENR-50 and it was found that the diffusion model (D1) agreed with ENR-50 degradation data

Effect of zinc borate on mechanical and dielectric properties of metallocene linear low-density polyethylene/rubbers/magnesium oxide composite for wire and cable applications

The effect of zinc borate (ZB) quantity on the mechanical and dielectric properties of 20 phr magnesium oxide/10 % rubbers (9/1 NR/ENR-50)/metallocene linear low-density polyethylene (mLLDPE) in the presence of N,N-m-phenylene bismaleimide (HVA-2) compatibilizer was investigated for wire and cable applications. With the increase in ZB loading, the tensile strength and the elongation-at-break of the composites decreased while the tensile modulus increased. In all composites, the strain-induced crystallization phenomenon at 200 % elongation was being observed in the stress–strain curves. Moreover, the dielectric strength, dielectric loss, permittivity and volume resistivity at frequency of 50 Hz were investigated. The permittivity of all composites increased with a rise in the voltage within the range of 1–5 kV. The loading of ZB in the composites improved the permittivity and volume resistivity as compared to the neat mLLDPE. The dielectric loss increased and 2 phr ZB composite displayed the highest dielectric loss among all other composites. On the other hand, the breakdown decreased with increasing ZB loading and the highest breakdown was observed in the 6 phr ZB composite. It was concluded that all composites are suitable for wire and cable application and the best result based on dielectric properties was observed in the 6 phr ZB composite

Effect of natural rubber/epoxidized natural rubber (90/10) on dielectric properties and crystallization of metallocene linear low density polyethylene

The effects of different amounts of natural rubber/epoxidized natural rubber (90/10 NR/ENR-50) blended with metallocene linear low density polyethylene (mLLDPE) with HVA-2 compatibilizer on the permittivity, dielectric loss, breakdown and volume resistivity at frequency of 50 Hz were investigated. Increasing the voltage with a range 1-5 kV increased the permittivity of both virgin mLLDPE and its blends. The permittivity, dielectric loss and breakdown of mLLDPE continuously decreased with increasing rubber content, but the AC volume resistivity of mLLDPE continuously increased with the rubber content. The degree of crystallinity of the mLLDPE composites was determined by differential scanning calorimetry. The lowest crystallinity and the maximum density of physical cross-links were observed in 10% rubber/mLLDPE blend. Increasing the proportion of rubber decreased the melting points of the blends. The FTIR showed that the epoxy groups and double bonds were absent from all the blends while the carbonyl group appeared in all cases