Modulating the surface and mechanical properties of textile by oil-in-water emulsion design

The synergistic effect of oil viscosity and oil droplet size on the deposition profile of oil on cotton fabric was studied using polydimethylsiloxane (PDMS) as a model oil-in-water emulsion system.

Design of industrial wastewater demulsifier by HLD-NAC model

The chemical method is one of the treatment techniques for the separation of oil–water emulsion systems. The selection of appropriate demulsifiers for each emulsion system is the most challenging issue. Hydrophilic-lipophilic-deviation (HLD) is a powerful semi-empirical model, providing predictive tools to formulate the emulsion and microemulsion systems. This work aims to apply HLD to obtain an optimal condition for demulsification of oil-in-water emulsion system—real industrial wastewater—with different water in oil ratios (WOR). Therefore, the oil parameter of the contaminant oil and surfactant parameter for three types of commercial surfactants were calculated by performing salinity scans. Furthermore, the net-average-curvature (NAC) framework coupled with HLD was used to predict the phase behavior of the synthetic microemulsion systems, incorporating solubilization properties, the shape of droplets, and quality of optimum formulation. The geometrical sizes of non-spherical droplets (Ld, Rd)—as an indicator of how droplet sizes are changing with HLD—were consistent with the separation results. Correlating Ld/Rd at phase transition points with bottle test results validates the hypothesis that NAC-predicted geometries and demulsification behavior are interconnected. Finally, the effect of sec-butanol was examined on both synthetic and real systems, providing reliable insights in terms of the effect of alcohol for WOR ≠ 1.

Development of Ficus religiosa extract-loaded emulsion system for topical application: Characterization and stability evaluation

Purpose: To develop, optimize and characterize a topical (W/O) emulsion containing 4 % Ficus religiosa extract for cosmeceutical purposes. Methods: The ethanol extract of Ficus religiosa was obtained by Soxhlet method. Various formulations were developed using paraffin oil, emulsifier (Abil®-EM 90) and purified water at different proportions, and their physical stability was assessed under different stress conditions, to enable selection of the most stable formulation. The optimized formulation based on stability studies was chosen for evaluation of different physical properties, i.e., color, liquefaction, phase separation, centrifugation, pH, droplet size and rheology, under accelerated conditions for 12 weeks. Results: The optimized formulation (F4) contained ethanol extract (4.0 %), Abil®-EM 90 (3.5 %), paraffin oil (14.0 %) and purified water (78.5 %), and remained stable on centrifugation under all stress conditions. The pH of the formulation remained within the specified range for human skin pH i.e. 4.5 – 6.0, and droplet size of dispersed phase also persisted within the size range of macroemulsion (1 – 100 μm) throughout the study period. Rheological properties of the formulation showed shear thinning response, and flow index value less than 1 resulted in pseudoplastic flow of emulsion. Conclusion: These results suggest that the optimized emulsion system was stable and can serve as a good medium for topical delivery of various natural substances.

EXTRACTION OF RUBBER FROM LATEX BY HYBRID COAGULANT BASED ON POLYDIMETHYLDIALLYLAMMONIUM CHLORIDE AND VISCOSE FIBER

In the proposed work, the possibility of using a hybrid coagulant based on a polymer cationic electrolyte-VPK – 402 (poly-N,N-dimethyl-N, N-diallylammonium chloride) in combination with viscose fiber in the technological process of separating SKS-30 ark rubber from latex is considered. The influence of the consumption of a hybrid coagulating agent, viscose fiber and its dosage, as well as the process temperature on the reduction of the aggregate stability of styrene-butadiene latex is considered. The influence of viscose fiber on the physical and mechanical properties of vulcanizates is established. At the same time, a number of features were noted consisting in a decrease in the aggregate stability of latex butadiene-styrene rubber during its coagulation with a hybrid coagulant. It was found that the use of a hybrid coagulant can reduce the consumption of cationic polyelectrolyte by up to 30%. It is shown that in the multicomponent system under consideration, several processes can occur simultaneously, which lead to the destabilization of latex dispersions. The use of a hybrid coagulant, including cationic polyelectrolyte, provides a combined effect of the bridging and neutralization mechanisms of violation of the aggregate stability of the dispersion. The presence of viscose fiber in the dispersed phase leads to an additional coagulating effect-adagulation, which is a kind of heterocoagulation. This may be due to the difference in surface potentials between the latex globules and the fiber additive. It is established that the temperature regime of the process of isolation of rubber from latex does not significantly affect the completeness of the extraction of rubber from latex. A decrease in the content of components of the emulsion system in wastewater discharged from the shops producing rubbers by emulsion polymerization was noted. According to the main physical and mechanical parameters, rubbers, rubber mixtures and vulcanizates prepared on their basis meet the requirements.