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Vegetable oils were investigated as plasticizers to improve the sustainability of rubber compounding. The potential use of different vegetable oils as an alternative to petroleum‐based rubber process oils was reviewed. This article presents a literature review on the current understanding of the influence of vegetable oil properties on natural rubber (NR) compounding. Hansen solubility parameters of the vegetable oils were determined to assist with the selection of vegetable oil for NR. We believe that the use of Hansen parameters could make the use of vegetable oils in rubber more convenient and cost‐effective.

The kinetics of the epoxidation of castor oil in benzene with peracetic acid formed in situ from acetic acid and hydrogen peroxide in the presence of an ion-exchange resin as a catalyst was studied. Eighteen pseudo-two-phase models are established that, besides the main reactions of peracid and epoxy ring formation, also consider the side reaction of epoxy ring cleavage with acetic acid. Kinetic expressions for the heterogeneously catalyzed peracetic acid formation are developed on the basis of Eley–Rideal and Langmuir–Hinshelwood–Hougen–Watson postulates. An equation derived for the temperature dependency of the chemical equilibrium constant for peracetic acid formation is applied. Kinetic and adsorption parameters were estimated by fitting experimental data using the Marquardt method. The best-fit model correctly interprets data of double bond and epoxy group contents as a function of reactant ratios, catalyst concentrations, and temperatures applied during epoxidation. The proposed model better fits experimental data than the pseudohomogeneous model reported in the literature.

A kinetic model was proposed for the epoxidation of vegetable oils with peracetic acid formed in situ from acetic acid and hydrogen peroxide in the presence of an acidic ion exchange resin as a catalyst. The model is pseudo-homogeneous with respect to the catalyst. Besides the main reactions of peracetic acid and epoxy ring formation, the model takes into account the side reaction of epoxy ring opening with acetic acid. The partitioning of acetic acid and peracetic acid between the aqueous and organic phases and the change in the phases? volumes during the process were considered. The temperature dependency of the apparent reaction rate coefficients is described by a reparameterized Arrhenius equation. The constants in the proposed model were estimated by fitting the experimental data obtained for the epoxidations of soybean oil conducted under defined reaction conditions. The highest epoxy yield of 87.73% was obtained at 338 K when the mole ratio of oil unsaturation:acetic acid:hydrogen peroxide was 1:0.5:1.35 and when the amount of the catalyst Amberlite IR-120H was 4.04 wt.% of oil. Compared to the other reported pseudo-homogeneous models, the model proposed in this study better correlates the change of double bond and epoxy group contents during the epoxidation process. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III45022]

The liquid-liquid equilibrium constant for acetic acid in a quinary system olive oil-epoxidized olive oil-acetic acid-hydrogen peroxide-water was experimentally determined for temperatures and component ratios relevant for in situ epoxidation of plant oils. The values have the constant range from 1.52 to 2.73. To predict the equilibrium constant for acetic acid, the experimental data were correlated with UNIQUAC (universal quasi chemical) and NRTL (non-random two liquid) activity coefficient models. For simplified calculation of the phase equilibrium the insolubility of olive oil and epoxidized olive oil in the water, as well as insolubility of water and hydrogen peroxide in the olive oil and epoxidized olive oil, was assumed. The root mean square deviation (RMSD) of the experimental and calculated values of the liquid-liquid equilibrium constant for acetic acid is 0.1910 for the UNIQUAC model and 0.1815 for the NRTL model. For rigorous flash calculation, when the partitioning of all components between the phases was assumed, the RMSD for the NRTL model is 0.1749.

Polycarbonate-based polyurethane (PC-PU) nanostructured composites were obtained using a one-step technique, by the addition of 1 wt.% organically modified clays (either bentonite or montmorillonite). Only aliphatic components (polycarbonate diol, hexamethylene-diisocyanate and 1,4-butane diol) were used as reactants. The hard segment content of the obtained polyurethanes was 30 wt.%. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) were performed to investigate the morphology and hydrogen bonding formation in prepared elastomers. The influence of nanofiller addition on thermal properties of PC-PUs was studied using differential scanning calorimetry (DSC). The degree of phase separation of polyurethane nanocomposites was not influenced by the dispersion of silicate layers in the elastomeric matrix. It was determined that bentonite and montmorillonite affect the melting transition of hard segments and the recrystallization process, which is very important for the processing and recycling of the prepared polyurethane hybrid materials.

Article Highlights • Linseed oil was used as renewable raw material to produce epoxides • Epoxidation was conducted as batch process at approximately isothermal conditions • Response surface methodology was applied to optimize the epoxidation process • Relative epoxy yield was chosen as an objective function for the optimization • At the optimal conditions, product with high oxygen epoxy content was obtained

The rubber compounds are obtained by blending natural or synthetic rubber, reinforcing fillers, rubber extender oil and other additives. Choosing the best components for rubber compounding are essential in rubber industry. The main function of rubber process oil (extender oil) is to reduce viscosity and improve mobility of the rubber chains and thus enable better processing and dispersion of the filler particles. Mineral oils, particularly aromatic ones, were widely used as extender oil in rubber industry, however, due to their influence on environment and the toxicity, there is a demand for their replacement in rubber compounds. One of the environmentally friendly extender oils with possible use in the compounding process as processing aids are epoxidized vegetable oils. In this study, influence of the epoxidizes soybean oil as extender oil on the properties of compound based on natural rubber was investigated. Characteristics of epoxidizes soybean oil as extender oil was experimentally measured or calculated. The experiments were performed on a laboratory internal batch mixer, at the constant temperature of 90°C and a rotor speed of 60 rpm. The hardness, tensile strength, elongation at break, modulus at 100 and 300% elongation, and rheological properties of rubber compounds were determined. Power consumption during rubber compounding mixing phase was calculated on the basis of experimentally measured voltage and amperage.