No abstract

No abstract

No abstract

No abstract

In this work, zinc borate was used as a flame retardant in ethylene vinyl acetate/magnesium hydroxide or aluminum hydroxide flame-retardant formulations. High content zinc borate leads to significant improvements of flame retardancy through limiting oxygen index, UL-94 and cone calorimeter experiments. The protective char formation revealed significant structural modifications due to the presence of zinc borate. It was demonstrated that during polymer heating, aluminum hydroxide and magnesium hydroxide decomposed to Al2O3 and MgO which resulted an increase in ignition time. Moreover, formation of Al2O3 or MgO in situ from aluminum hydroxide or magnesium hydroxide during polymer combustion is the first event. Concurrently, zinc borate degraded and formed a vitreous protective coating, which yielded the substrate with an efficient char which acted as a physical barrier and a glassy cage for better protection of polymer substrate.

Graphene (Gr) distribution in low‐density polyethylene (LDPE) and ethylene vinyl acetate (EVA) considerably increased thermal stability and mechanical properties of LDPE/Gr or EVA/Gr composites. Dynamic mechanical analysis (DMA) and strength testing machine were used to study mechanical properties. The high specific surface areas and superior properties of Gr improved thermal strength, storage modulus, and mechanical properties of composites. Outstanding distribution of Grs was accomplished and verified by atomic force microscopy. LDPE/Gr and EVA/Gr composites were characterized by transmission electron microscope (TEM), X‐ray diffraction, and thermogravimetric analyses to study the distribution morphology and thermal strength. Results display that the presence of filler does not create an alteration in the microscopic structure of polymers. Measurement of tensile properties shows that the tensile strength of composites contains Gr is significantly higher than similar values for pure EVA and LDPE. The DMA shows that the storage modulus of composites is much greater than that of pure EVA and LDPE. The thermal stability of the composite contains Gr is also considerably higher than that of pure EVA and LDPE. J. VINYL ADDIT. TECHNOL., 24:E177–E185, 2018. © 2018 Society of Plastics Engineers

The creation of oil emulsions due to mechanical strength and natural surfactants during production is undesirable. The challenges associated with transporting and refining oil have led researchers to probe into practical demulsification methods. An in-depth understanding of crude oil rheology and operating conditions to treat emulsion is necessary. The main objective of the current study was to investigate the rheological behavior and demulsification rate of crude oil emulsions. The rheological behavior of a crude oil emulsion was studied by manipulating its temperature (30 °C–90 °C), shear rate (0.1–1000 s–1), and water volume fraction (20%, 30%, and 40%). For emulsions of various water content, the rheological studies followed the non-Newtonian shear thinning behavior, which was explained effectively by the Herschel–Bulkley model. Experimental results also indicated that the measured viscosity of emulsion decreased significantly with temperature, while increasing water volume fraction increased viscosity. The rates of demulsification of water in crude oil emulsion in direct current fields were investigated under various conditions by using an electrochemical cell. The separation rate of water increased along with the applied field, water content, and salt concentration. Results of this study indicated that emulsion separation was governed by the magnitude of the applied electric field as well as the type of electrode.

No abstract