Average Particle Size Of Emulsion Research Articles

Construction of Pickering emulsion and its application in enzymatic synthesis of phytosteryl oleate

In this study, Janus nanoparticles were prepared and used to construct Pickering emulsion as an emulsifier in presence of lipase. The results showed that Janus nanoparticles could be used to stable water phase in emulsion and the average particle size of emulsion was 60 μm. Phytosterol ester was successfully synthesized in Pickering emulsion catalytic system by using oleic acid as acyl accepter, and the phytosterol conversion reached 91.65 ± 2.07% under the following conditions: emulsifier amount of 1.0 wt%, oil-water ratio of 6:1, phytosterol concentration of 110 mmol/L, lipase dosage of 20 g/L, reaction temperature of 45 °C. Compared with biphasic catalytic system, Pickering emulsion catalytic system could enhance the catalytic efficiency and shorten the reaction time due to large interface area and short molecule diffusion distance. At the end of reaction, Janus nanoparticles could be recovered by simple centrifugation, the relative activity of lipase remained 72.89 ± 1.83% after repeated use for 6 times. Overall, this paper provides a novel and high efficiency interfacial biocatalysis technique for the synthesis of phytosteryl oleate.

A Feasibility Study on Enhanced Oil Recovery of Modified Janus Nano Calcium Carbonate-Assisted Alkyl Polyglycoside to Form Nanofluids in Emulsification Flooding.

Emulsification flooding can effectively enhance crude oil recovery to solve the problem of petroleum shortage. In this work, a modified Janus Nano Calcium carbonate (JNC-12) with a particle size of 30-150 nm was synthesized, and an in situ emulsification nanofluid (ISEN) was prepared with JNC-12 and alkyl polyglycoside (APG). Scanning electron microscope (SEM) showed that the dispersion of JNC-12 in air or APG solution was better than Nano Calcium carbonate (Nano CaCO3). The emulsification properties, interfacial tension, and expansion modulus of ISEN were studied, and the result showed that with the increase in salinity, the emulsification rate decreased, the water yield rate increased, the interfacial tension first decreased and then increased, and the expansion modulus first increased and then decreased. With the increase in temperature, the emulsification rate, emulsion viscosity, and interfacial tension decreased. With the increased oil-water volume, the water yield rate and the emulsion viscosity increased. With increase in the concentration of JNC-12, the water yield rate, the emulsion viscosity, and the interfacial tension decreased but the expansion modulus increased. The emulsion generated by emulsifying ISEN with crude oil was an O/W emulsion, the crude oil viscosity was 4-10 times that of emulsion, and the average particle size of emulsion was 1.107 μm. The addition of ISEN caused the decrease in interfacial tension of oil-water to 0.01-0.1 mN/m. The wettability alteration experiment found that ISEN could change the lipophilic rock to hydrophilic rock. Finally, the core displacement experiments showed that compared with the first water flooding, the oil recovery of the second water flooding after ISEN flooding enhanced by 17.6%. This research has important guiding significance for in situ emulsified nanofluid flooding to enhance oil recovery.

Synthesis and characterization of non-ionic flame-retardant waterborne polyurethane.

Waterborne polyurethane (WPU) offers many advantages and is widely used in coatings, leathers, adhesives, biomaterials, and other consumer products. However, WPU is highly flammable. Many reactive flame retardants have been developed, but their char formation efficiency is still unsatisfactory, and the melt dripping during combustion has not been effectively suppressed. In this paper, a novel phosphorus-containing flame retardant with dihydroxy groups, (6-((4-hydroxyphenyl)((4-hydroxyphenyl)amino)methyl) dibenzo[c,e][1,2]oxaphosphinine 6-oxide) (PHAD), was successfully synthesized and incorporated into WPU molecular chain as a chain extender, thereby synthesizing a series of non-ionic flame-retardant waterborne polyurethane (NFRWPU) emulsions. The chemical structure of NFRWPU was successfully characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance. With the help of a thermogravimetric analyzer, scanning electron microscope and other instruments, some key performance parameters of NFRWPU in applications were investigated, including: physical, mechanical, and thermal stability and flammability. Some important experimental results include: both the particle size and viscosity of the emulsion increase gradually with increasing PHAD content, and when the PHAD content reaches 12%, the average particle size of emulsion increases to 106.6 nm with a viscosity of 89 mPa s; with the addition of PHAD, the tensile strength of NFRWPU initially increased and then decreased, while the elongation at break showed a continuous downward trend. The maximum tensile strength reached 22.63 MPa, and the minimum elongation at break dropped to 1060%; the addition of PHAD improved the thermal stability and flame retardancy of the film, with the highest limiting oxygen index value reaching 25.6% and the maximum carbon residue increasing to 6.5%. All these results indicate that NFRWPU is a promising flame retardant WPU considering the comprehensive performance.

Preparation and characterization of a self-matting waterborne polyurethane with antibacterial function

Self-matting waterborne polyurethane (WPU) with rough surface is often accompanied by poor antibacterial property, which greatly limits its service life. Here, a gemini quaternary ammonium (GQM) with hydrophilic and antimicrobial properties was designed and synthesized. 1,3,5-tris (2-hydroxyethyl) hexahydro-1,3,5-Triazine (TNO) was used as a crosslinking agent, and GQM was selected as chain extender to prepare antibacterial and self-matting WPU resin. The effects of TNO and GQM on the morphology, particle size, gloss, antibacterial rate, and hydrophilicity of WPU were investigated. The results showed that the introduction of TNO and GQM significantly enhanced the self-matting effect and antibacterial activity of WPU. When the contents of TNO and GQM were 1.2 wt% and 4 wt%, the average particle size of emulsion was 6.53 μm, the gloss of coating was 11.05 GU. It is also significant to be noted that the antibacterial rates of S. aureus and E. coli were 95.69 % and 95.18 %, respectively. This prepared WPU was endowed with self-matting and antibacterial properties simultaneously. This finding can provide a novel insight into the research of antibacterial polymers and antiglare coatings.

Microstructure and Mechanism of Polymer Cement

Styrene and butylacrylic acid copolymer emulsion (BA-St-MMA) was synthesized by pre-emulsification and semi-continuous process with styrene and butyl acrylic acid as main raw materials, and polymer sulfate cement was prepared by adding it into sulphoaluminates cement. The modification mechanism on BA-St-MMA to sulphoaluminates cement was researched by XRD, SEM-EDS, infrared analysis and pore structure analysis. The results show that the impermeability of cement mortar is improved by adding styrene-acrylic emulsion. With the increase of emulsifier content, the stability of emulsion polymerization increases, and the average particle size of emulsion decreases slightly, which is generally kept at 100. -between 140 nm. Under the condition of low cement accumulation ratio, the impermeability of cement mortar has the optimal value with the increase of emulsion content, and the seepage height is low.

The research about microscopic structure of emulsion membrane in O/W emulsion by NMR and its influence to emulsion stability

PurposeThis paper discussed the influence of microstructure of emulsion membrane on O/W emulsion stability. MethodsO/W emulsions were emulsified with equal dosage of egg yolk lecithin and increasing dosage of co-emulsifier (oleic acid or HS15). The average particle size and centrifugal stability constant of emulsion, as well as interfacial tension between oil and water phase were determined. The microstructure of emulsion membrane had been studied by 1H/13C NMR, meanwhile the emulsion droplets were visually presented with TEM and IFM. ResultsWith increasing dosage of co-emulsifier, emulsions showed two stable states, under which the signal intensity of characteristic group (orient to lipophilic core) of egg yolk lecithin disappeared in NMR of emulsions, but that (orient to aqueous phase) of co-emulsifiers only had some reduction at the second stable state. At the two stable states, the emulsion membranes were neater in TEM and emulsion droplets were rounder in IFM. Furthermore, the average particle size of emulsions at the second stable state was bigger than that at the first stable state. ConclusionsEgg yolk lecithin and co-emulsifier respectively arranged into monolayer and bilayer emulsion membrane at the two stable states. The microstructure of emulsion membrane was related to the stability of emulsion.

Effect of total acrylic/fluorinated acrylic monomer contents on the properties of waterborne polyurethane/acrylic hybrid emulsions

Stable emulsions of waterborne poly(urethane-urea) (WBPU, soft segment content: 57 wt%, dimethylol propionic acid: 19 mol%/5.8 wt%)/n-butyl acrylate (BA)/glycidyl methacrylate (GMA)/perfluorodecyl acrylate (PFA) (weight ratio of BA/GMA/PFA: 5/3/2) hybrid materials containing 0-30 wt% of acrylate content (fluorinated acrylate content: 0–6 wt%) were successfully prepared by an emulsifier-free/solvent-free prepolymer mixing process. However, the as-polymerized hybrid emulsion containing 40 wt% of acrylic monomer content was found to be unstable, indicating that near 40 wt% in acrylic monomer content was beyond the limit of the self-emulsifying ability. By the curve fitting analysis of IR-peaks and X-ray photoelectron spectroscopy (XPS) analysis, the C-F content was found to increase with the increase in acrylate content. The average particle size of emulsion, young modulus/ yield point in stress-strain curve, hardness, thermostability, and water/methylene iodide-contact angles of the film sample increased with increasing acrylate content. However, the viscosity of emulsion, the elongation at break, water swelling and surface energy of film samples were significantly decreased with increasing acrylate content. The tensile strength of film sample decreased a little with increasing acrylate content. These results point to the strong potential of WBPU (70 wt%)/acrylate copolymer (30 wt%) hybrid as a coating material with the lowest surface energy (18.18 mN/m) and the highest contact angles (water: 111.76o, and methylene iodide: 79.95°). Open image in new window

Synthesis of Emulsion for Water-Based Pigment Ink Jet

The water-based pigment ink jet emulsion whose particle size was less than 100nm was synthesized by the polymerization of methyl methacrylate, butyl acrylate and ethylhexyl acrylate, and anionic reactive surfactant and nonionic surfactant were used as the emulsifiers. The effects of particle size and water resistance were studied. The glass transition temperature was tested by differential scanning calorimetry. The average particle size of emulsion was range from 60nm to70nm, zeta potential value was less than -60mv; viscosity was 3.5mps; water absorption was 5.9%.

Synthesis of Styrene-Acrylic Emulsion for Aqueous Glazing Agent

The water-based pigment ink jet emulsion whose particle size was less than 100nm was synthesized by the polymerization of methyl methacrylate, butyl acrylate and ethylhexyl acrylate, and anionic reactive surfactant and nonionic surfactant were used as the emulsifiers. The effects of particle size and water resistance were studied. The glass transition temperature was tested by differential scanning calorimetry. The average particle size of emulsion was range from 60nm to70nm, zeta potential value was less than -60mv; viscosity was 3.5mps; water absorption was 5.9%.