Emulsifier Dosage Research Articles

Genipin crosslinked gum arabic: Synthesis, characterization, and emulsification properties

Although recognized as a “gold standard” emulsifier in food industry, gum arabic (GA) is characterized by high dosage consumption and inconsistent emulsification performance. This work aimed to solve the above shortcomings by crosslinking GA with genipin. The resulting genipin-crosslinked GA (G-GA) had larger molecular weight (1596 kg/mol) and mean radius of gyration (64.9 nm) than the control GA (denoted as C-GA; 529 kg/mol and 19.2 nm), featuring a more compact conformation. More importantly, the proportion of the arabinogalactan protein (AGP) component of G-GA increased, endowing G-GA with enhanced emulsifying stability. The dosage required for emulsification were less for G-GA (7.5 %) than C-GA (15 %) in 20 % oil emulsion. The G-GA-stabilized emulsions sterilized (110 °C for 30 min) or treated at 60 °C for 10 d were more stable. Overall, this study demonstrates that genipin crosslinking is a suitable strategy providing GA with enhanced emulsification properties while saving the emulsifier dosage.

Systematic approach to address challenges in microsurfacing mix design

This paper presents a systematic laboratory approach for microsurfacing mix design to address the challenges faced due to multiple components and associated chemical complexity. A comprehensive laboratory study was undertaken to understand the variation in microsurfacing mix performance with respect to filler characteristics, mineral filler and emulsion components including emulsifier dosage, asphalt binder type and solvent. First, replacement of filler was done to address the issue of pre-mature breaking which was related to very high reactivity of aggregates. Next, the type and dosage of mineral filler was selected using cohesion test. Interestingly, the combination of cement (2%) and fly ash (1%) imparted highest cohesion highlighting the benefits associated with incorporation of waste materials having pozzolanic characteristics in the mix. In terms of emulsion components, use of higher emulsifier dosage showed a delay in the curing process which in turn, resulted in inferior cohesion, raveling and rutting resistance. Further, incorporation of harder asphalt binder and the use of solvent during emulsion production resulted in reduction in rutting by>61%. Raveling resistance was also found to be dependent on the use of solvent indicating the importance of maintaining equiviscous temperature during emulsion production. From the results, a narrow range diagram illustrating the acceptable range of emulsion content considering all design parameters was recommended to determine optimum emulsion content (OEC). The mid-point of acceptable emulsion content range was termed as OEC which, in the present study, was found to be 14% by dry weight of aggregates.

Pretilachlor Releasable Polyurea Microcapsules Suspension Optimization and Its Paddy Field Weeding Investigation.

In this study, pretilachlor was encapsulated into polyurea microcapsules prepared by water-initiated polymerization of polyaryl polymethylene isocyanate and eventually made into pretilachlor microcapsules suspension (PMS). We used response surface methodology (RSM) combined with the Box–Behnken design (BBD) model to optimize the formulation of PMS. The encapsulation efficiency (EE) of PMS was investigated with respect to three independent variables including wall material dosage (X1), emulsifier dosage (X2), and polymerization stirring speed (X3). The results showed that the regression equation model had a satisfactory accuracy in predicting the EE of PMS. To achieve an optimal condition for PMS preparation, the dose of wall material was set to 5%, the dose of emulsifier was set to 3.5% and the polymerization stirring speed was set to 200 rpm. The EE of PMS was up to 95.68% under the optimized condition, and the spherical shape with smooth surface morphology was observed. PMS was also proven to have delayed release capability and in vivo herbicidal activity against barnyard grass [Echinochloa crusgalli (L.) Beauv.] with an LC50 value of 274 mg/L. Furthermore, PMS had efficient weed management compared to commercially available 30% pretilachlor emulsifier (PE), showing a promising potential application for weeding paddy fields.

Ultraviolet light-initiated preparation of phase change material microcapsules and its infrared imaging effect on fabric

PurposeThis study aims to explore the infrared imaging effect of fabrics coated with phase change material microcapsules (PCM-MCs), which are prepared by the initiation of ultraviolet (UV) light.Design/methodology/approachPCM-MCs were prepared by UV polymerization using paraffin (PA) as core material, polymethyl methacrylate as wall material and ferric chloride as photoinitiator. The effects of emulsifier dosage and emulsification temperature on the properties of PA emulsion were investigated. Scanning electron microscopy, particle size analysis, infrared spectroscopy, differential scanning calorimetry and infrared imaging test were used to characterize the properties of microcapsules.FindingsThe PCM-MCs with good morphology and particle size were prepared with 25 cm of the distance between light source and the liquid. The average particle size was 1.066 µm and the latent heat of phase transition was 19.96 J/g. After 100 accelerated thermal cycles, the latent heat only decreased by 1.8%. It had good heat storage stability and thermal stability. The fabric coated by the microcapsules exhibited a variable temperature hysteresis effect when placed in the sun, and presented a color close to the infrared images of the human palm under the external environment temperature close to the human body temperature.Research limitations/implicationsThe PCM-MCs prepared based on UV light initiation showed good thermal properties and its coated fabrics had an infrared decoy effect below the temperature of the human body.Practical implicationsThis study explored the application of microcapsules in textiles.Originality/valueThe microcapsules had a certain application potential in infrared decoy effect.

Preparation and reshaping of composite microparticles for color toner based on the encapsulated nanoparticles

AbstractIn this paper, the styrene–acrylic resin‐encapsulated organic pigment composite nanoparticles were synthesized by mini‐emulsion polymerization first, and then the aggregated microparticles used for color toner were prepared via the emulsion aggregation method. Transmission electron microscopy, dynamic light scattering, and zeta potential analysis manifest that when the emulsifier dosage was 5 wt% of the monomer, the composite nanoparticles owned clearly core‐shell structure, uniform size, and appropriate zeta potential, which was conducive to the subsequent aggregation. The evolution of aggregated particle size and morphology under different stirring rates, coagulant concentrations, and temperatures was investigated by mastersizer and scanning electron microscopy. The result shows that when the stirring rate was 1,000 rpm, coagulant concentration was 0.2 mol/L, and the curing temperature was 65°C, aggregated particles with suitable size, narrow size distribution, and regular shape could be obtained. The reshaping of aggregated particles can further improve their morphology. When the reshaping temperature was 75°C, the product particles owned perfect spherical shape, and there were almost no cracks and pores on the surface of the particles. This synthesis strategy is believed to provide a guide for the fabrication of composite microparticles with controllable particle size and morphology.

Synthesis and Self-Healing Mechanism of Self-Healing Epoxy Microcapsule Materials

Self-healing epoxy resin microcapsules are prepared by interfacial polymerization, in which the core materials are epoxy resin, the wall materials are constructed with triethylenetetramine and the epoxy resin. The orthogonal experimental L9(34) are designed to investigate the influence of emulsifier dosage, hardener dosage, curing temperature and hardener adding rate on the core content and storage life of epoxy resin microcapsule. Scanning electron microscope is used to characterize surface topography and distribution. Fourier transform infrared spectroscopy is used to study reaction mechanism of the microcapsule wall materials, respectively. The results indicate that when the dosage of emulsifier is 1.2%, the dosage of hardener is 1.2%, the hardener droplets adding rate is 1.2 g/h and the curing temperature is 50°C, the prepared microcapsules with a high level of core content are spherical in shape with good surface compactness and dispersibility. Future research may focus on improving microcapsule storage stability and the obstacles encountered in practical applications.

Formulation optimization of D-limonene-loaded nanoemulsions as a natural and efficient biopesticide

D-limonene is an important constituent of citrus fruits, such as oranges and lemons, and can be extracted as a natural essential oil for controlling the agricultural pests because of its antifungal and insecticidal activities. However, the hydrophobicity of D-limonene hinders its full potential and excellent performance. In this research, the effect of emulsifier type, dosage, and emulsification method on the formation and stability of D-limonene-loaded nanoemulsions was investigated by sample appearance, microstructural observations, droplet size measurement, and multiple light scattering analysis. Nanoemulsions prepared with emulsifier (EL-40) exhibited the highest stability, with an appropriate HLB (Hydrophilic Lipophilic Balance) value of 13.5. The stability of nanoemulsions increased at higher emulsifier dosage from 2% to 6%. Also, nanoemulsions fabricated by dropwise addition of aqueous phase (deionized water) into D-limonene as the oil phase premixed with emulsifier were the most stable samples. The optimized formulation of D-limonene-loaded nanoemulsions was determined as: 10 % D-limonene, 6% EL-40, and 84 % deionized water. The quality indicators of this formulation were acceptable in terms of FAO standards. Finally, D-limonene-loaded nanoemulsions could inhibit the growth of various fungal pathogens, including Pyricularia oryzae (rice blast), Rhizoctonia solani (rice sheath blight), Colletortrichum gloeosporiodes (pepper anthracnose), and Phomopsis amygdali (peach shoot blight). This research provides a practical solution for the formulation of stable and effective nanoemulsions containing D-limonene for the control of agricultural crop diseases.

Preparation, stability and film properties of cationic polyacrylate latex particles with various substituents on the nitrogen atom

Cationic latexes have received wide attention due to their special properties and potential applications in wood coatings, fabric treatment, etc. However, the practical application of cationic latexes was hindered due to their poor stability, especially the alkali resistance stability. In this work, various stable cationic polyacrylate latexes were prepared by an efficient route. Three cationic comonomers, i.e., methacrylatoethyl trimethyl ammonium chloride (DMC), 2-(dimethylamino)ethyl methacrylate (DMAEMA), and 2-aminoethyl methacrylate hydrochloride (AEMH), were used in the aqueous semi-continuous seeded emulsion polymerization of methyl methacrylate (MMA) and butyl acrylate (BA) using cetyl trimethyl ammonium bromide (CTAB) and 2,2′-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (AIBI) as the cationic emulsifier and initiator, respectively. The alkali resistance of the latex could be significantly improved by the addition of cationic monomer DMC and be simply tuned by adjusting DMC dosage. The improved stability of the latex might originate from the higher charge density on the surface of the latex by the introduction of DMC. Moreover, the effects of initiator dosage, emulsifier dosage and different cationic comonomers on the latex preparation and the film properties were also systematically investigated. This work not only introduces an efficient route to prepare cationic latexes with superior stability, but also paves the way for latexes to be used in applications such as textile finishing, paper industry, and biomedical field, etc.

Preparation and Repeated Repairability Evaluation of Sunflower Oil-Type Microencapsulated Filling Materials.

Cracks are the main challenges for asphalt pavement, which should be timely repaired. One of the most commonly used repairing methods is to fill the binding materials into cracks, but the repeated repairing ability is insufficient. The self-healing microcapsule technologies provide the potentials for enhancing the repeated repairing ability of filling materials. Therefore, the microcapsule core material was selected from sunflower oil in this study, and the capsular wall material was selected from melamine-urea-formaldehyde resin, which was used to prepare the microcapsule by using in-situ polymerization method. Three kinds of microcapsules with different particle sizes were prepared by adjusting the emulsifier dosage and core wall ratio. The microstructure, molecular structure, thermal stability, and dispersion features were further studied, and the effects of microcapsules with different particle sizes on the repeated repairability of the filling materials were evaluated via the fatiguerepair-fatigue test. In addition, the traditional regenerative microcapsules were compared to determine the optimal particle size range for sunflower oil microcapsules. According to the experimental research, it was thus concluded that the emulsion droplet size distribution was most concentrated when the emulsifier content was 0.7%; and when the core-wall ratio was 1.3:1, the microcapsules had uniform particle size and good dispersion effect. When the microcapsule emulsification rate was 900 rpm and microcapsule content was 2%, then the repeated repair effect for the microcapsule crack filling materials was optimal. The sunflower oil type microcapsule therefore meets the filling temperature requirement for the filler.

Preparation of Polyurea Microcapsules Containing Phase Change Materials Using Microfluidics

The polyurea microcapsules containing phase change materials (MicroPCMs) are prepared by using a simple microfluidic device at low temperature. Paraffin is the core material, and isophorone diisocyanate (IPDI) and tetraethylenepentamine (TEPA) are the shell materials. Effects of the flow rate of each phase, the emulsifier type, and the emulsifier dosage on MicroPCMs are investigated systematically. The size of MicroPCMs can be controlled by changing the flow rate of each phase. Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) are used to characterize the chemical structure and morphology of the MicroPCMs, respectively. The images of SEM show that MicroPCMs have the regular spherical shape and a good size distribution. The results of FTIR indicate that MicroPCMs have been successfully prepared as the characteristic peaks of paraffin and polyurea are observed in the curve of MicroPCMs. The thermal properties and stabilities of MicroPCMs are investigated through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). When taking sodium dodecyl sulfate (SDS) as the emulsifier, the results show that the latent heat is 87.5 J/g with an encapsulation efficiency of 96.5% and the appropriate dosage of SDS is 1.0 g for synthesizing MicroPCMs. The results of TGA present that the polyurea shell can prevent the leakage and volatilization of the paraffin.

Emulsification and Performance Measurement of Bio-oil with Diesel

To overcome the drawbacks of pyrolytic bio-oil, such as high acidity, viscidity, corrosivity, oxygen content and low heating value, a novel method of emulsifying bio-oil with diesel was investigated in this study. The effects of various factors on the stability of emulsified oil were examined. The optimal emulsification conditions of diesel and bio-oil are by using an emulsifier (mixture of Span 80 and Tween 80) dosage of 6% by mass and co-emulsifier (2-octanol) dosage of 4% by the mass of emulsifier, hydrophile lipophilic balance value of 7, shear velocity of 15,000 rpm, emulsifying time of 5 min, and emulsifying temperature at 40 °C. The stability time of emulsified oil is up to 384 h under the above optimal conditions. Some fuel properties were also measured to characterize the emulsified oil. The results show that the density, viscosity, corrosivity and heating value of emulsified oil at the optimal conditions are close to those of diesel oil. In addition, the mechanism model for the emulsion of bio-oil and diesel was also proposed.

Investigating the dynamical stability of heavy crude oil-water systems using stirred tank

In petroleum industry, the stability of oil-water emulsions has a significant influence on multiphase flow and oil-water separation; however, there is a lack of quantitative research on the stability of heavy oil emulsions under flowing conditions. Here, emulsion stability was characterized by the free water fraction, and experiments using a stirred tank were carried out to investigate the stability of heavy crude oil emulsions. Sensitivity analysis of different variables such as temperature, shear rate, emulsifier dosage, salinity, and initial water fraction of oil-water mixture were conducted by measuring the free water after stirring. Free water fractions under flowing conditions were determined by extrapolation of the separated water fraction to the precise moment when stirring was stopped. Additionally, the viscosity of emulsions under corresponding experimental conditions was measured by the method of stirring. It was found that for partially emulsified heavy oil emulsion systems, the stability of the system increased with the initial water fraction, salinity, shear strength and emulsifier dosage, and decreased with the settling temperature. Based on the experimental results, a preliminary water separating fraction model (to evaluate the stability of the heavy crude oil-water system) and a viscosity model were proposed. The power law equation might well fit the data with relative deviation below 13.75% and 7.28%, respectively. The stability evaluation model and viscosity calculation model may prove beneficial in estimating pipeline flow conditions, and helping to design transportation arrangements in industrial applications.

Synthesis and reaction mechanism of self-healing epoxy microcapsules

Self-healing epoxy resin microcapsules are prepared by interfacial polymerization, in which the core materials are epoxy resin, the wall materials are constructed with triethylenetetramine (TETA) and the epoxy resin. The orthogonal experiments L9 (34) are designed to investigate the influence of emulsifier dosage, hardener dosage, curing temperature and hardener adding rate on the core content and storage life of epoxy resin microcapsule. Scanning electron microscope and static dynamic wide angle laser light scattering instrument synchronization are used to characterize surface topography, particle size and distribution. Fourier transform infrared spectroscopy and thermo-gravimetric analyzer are used to study reaction mechanism of the microcapsule wall materials and thermal stability of the microcapsules, respectively. The results indicate that when the dosage of emulsifier is 1.2%, the dosage of hardener is 1.2%, the hardener droplets adding rate is 1.2 g/h and the curing temperature is 50 °C, the microcapsules prepared are spherical in shape with good surface compactness, dispersibility and thermal stability and the capsule core content is 82.3% and the average particle size is 275.3 μm. However, this type of epoxy resin microcapsule has relatively poor chemical stability. The core content decreases by 2.0% after 12 d storedat room temperature. After epoxy resin composite doped with 2.0% mass fraction of 200~300 μm microcapsules is damaged by the tensile testing machine, their repair rate is 67.04%.

Stability of polyethylenimine solution‐in‐liquid paraffin emulsion for preparing polyamine microspheres with potential adsorption for ionic dyes

AbstractA microsphere synthesized by emulsion crosslinking of polyethylenimine (PEI) was applied in the removal of ionic dyes from water. Firstly, the stability of the PEI solution‐in‐liquid paraffin emulsion was improved by using the mixture of Span‐80/Tween‐80 as the emulsifier. The optimization by 25‐1 fractional factorial design demonstrated the most stable emulsion was prepared at 0.07 g/mL of the emulsifier dosage, 6:4 (v:v) of the oil/water ratio, 20 % (wt %) of the PEI concentration, 6:1 (w:w) of the Span‐80/Tween‐80 ratio with a homogenization speed of 6000 r/min for 3 min at 25 oC. Then, the polyamine microsphere (PA‐M) was obtained by crosslinking the PEI emulsion with glutaraldehyde. The PA‐M microsphere can adsorb xylenol orange (XO) from aqueous solution with a capacity of 1169.2±12.5 mg/g. The amount of XO adsorption remained constant in the pH range of 2.0‐11.0. Adsorption kinetics analysis demonstrated that Pseudo first‐order model fit the experimental data better, indicating the overall adsorption process was controlled by ‘surface reaction’. The XO adsorption on the microsphere was due to an electrostatic interaction according to the results of ΔG evaluation. The value of separation factor suggested the XO adsorption was favorable. The used PA‐M microsphere can be regenerated and reused in adsorption/desorption operation at least 20 times.

Hydrolysis of rapeseed oil to fatty acids using pyrrolidonium ionic liquids as catalysts

ABSTRACTThis study aimed to evaluate the hydrolysis of rapeseed oil using pyrrolidonium ionic liquids as catalysts under atmospheric pressure. The process parameters were optimized using a sequence of experimental protocols to evaluate the effects of ionic liquid loading, dosage of emulsifier, weight ratios of substrates, temperature and time. The results demonstrated that the ranking of catalytic activity of ionic liquids is N-methyl-2-pyrrolidonium hydrogen sulfate salt ([HNMP]HSO4)>1-(3-sulfonic acid) propyl-2-pyrrolidonium hydrogen sulfate salt ([C3SO3Hnhp]HSO4)>2-pyrrolidonium hydrogen sulfate salt ([Hnhp]HSO4). In a batch reactor, the hydrolysis reaction conditions in the presence of [HNMP]HSO4 were investigated and optimized as follows: catalyst loading of 20% (based on the weight of oil), oil/water weight ratio of 1:2, emulsifier loading dosage of 4 wt % (based on the weight of oil), hydrolysis temperature of 100°C, and hydrolysis time of 30 h. The catalytic performance of this ionic liquid remained excellent even after reuse five times.

Effects of Emulsifier Dosage and Curing Time on Self-Healing Microcapsules Containing Rejuvenator and Optimal Dosage in Asphalt Binders.

Micro-damages always occur and accumulate in asphalt pavement materials under the effects of temperature, vehicle loads and other factors during service. Accordingly, self-healing microcapsules could be added into asphalt binder and repair micro-damages to prevent damage extension in time. In this study, the emulsified rejuvenator and melamine-urea-formaldehyde resin (MUF) were selected as the core and cyst wall materials, respectively, and in-situ polymerization method was applied to synthesize the novel microcapsules. The effects of emulsifier dosage and curing time were revealed on the particle size, dispersion, surface morphology and coating properties, and the optimum process parameters were determined for microcapsules. Then, the micro morphology, molecular structure, and thermal stability were further investigated to determine the optimal preparation of the microcapsules. Finally, the linear amplitude sweep (LAS) test was performed to evaluate the self-healing efficiency of the asphalt binder with different dosages of prepared microcapsule, and the optimal dosage of microcapsules was determined as 0.5%.

Nanocapsules containing binary phase change material obtained via miniemulsion polymerization with reactive emulsifier: Synthesis, characterization, and application in fabric finishing

The nanocapsules containing n‐butyl stearate (BS) and n‐octadecane (C18) as binary phase change material and polyacrylate as shell were synthesized via miniemulsion polymerization using reactive emulsifier. The phase transition (change) temperatures and phase change enthalpies of the phase change material can be adjusted by regulating the composition of BS and C18. Moreover, the influences of emulsification method and reactive emulsifier dosage were studied. SEM and TEM analysis showed the nanocapsules were a spherical shape with core‐shell structure and the average size was about 170 nm. DSC and FT‐IR analysis indicated the binary phase change material was encapsulated with polyacrylate shell, and the fusing and crystallizing temperatures and latent heats of nanocapsules were determined as 26.07 °C and 24.85 °C, 56.89 J g−1 and 54.02 J g−1 respectively, and the encapsulation efficiency was above 55.09%. In addition, the results of thermoregulating and durability property revealed that the finished cotton fabric had temperature‐regulated and durability properties. POLYM. ENG. SCI., 59:E42–E51, 2019. © 2018 Society of Plastics Engineers

Preparation and Performance of an Oil-Soluble Polyethylene Wax Particles Temporary Plugging Agent

In order to solve the problem of low strength, low permeability recovery rate, and narrow suitable temperature range of the oil-soluble temporary plugging agent, the idea of preparing the oil-soluble polyethylene wax particles temporary plugging agent (OPPTA) using polyethylene wax as the main raw material was proposed. Emulsifier and stabilizer were selected, and the dosage of emulsifier, stabilizer, and stirring speed was optimized. The method for preparing OPPTA was formed. The temporary plugging performance of OPPTA for the natural core was studied. The plugging rate and the recovery rate of core permeability after plugging removal of OPPTA were 99.9% and 90.1%, respectively. The temporary plugging performance of OPPTA was better than that of a conventional oil soluble temporary plugging agent W-11.

Preparation and characterization of self-healing microcapsules embedding waterborne epoxy resin and curing agent for asphalt materials

In this paper study, two kinds of self-healing microcapsules embedding waterborne epoxy resin (WER) and curing agent (CA) are synthesized by using the interfacial polymerization method, which could be incorporated into asphalt binders to prepare the novel self-healing materials and have the potential application to repair the micro-damage and micro-crack in asphalt materials. The two capsule-core materials were emulsified by using different emulsifier dosage and emulsification time, and the normal distribution characteristics of the particle size and quantity were statistically analyzed to determine the optimal emulsification solution. Then, ethylene glycol and toluene diisocyanate (TDI) were selected as the capsule-wall raw materials, and the microcapsules were prepared by using different core-wall materials ratio. The particle dispersion, surface morphology and coating properties were statistically analyzed to determine the optimal synthetization. FT-IR analysis results demonstrated that the microcapsules were successfully prepared by suing those optimized schemes. The optimal synthetization of WER microcapsules that 0.5% emulsifier dosage, emulsification for 16 min, core-wall materials ratio of 1.3:1, and the optimal synthetization of CA microcapsules is that 0.7% emulsifier dosage, emulsification for 16 min, core-wall materials ratio of 1:1. SEM and TG-DSC analysis results showed that the microcapsule particles were uniform, well-dispersed and regular in shape, and the capsule-wall thickness was about 1.0 μm. The thermal stability of the WER microcapsules is better than the CA microcapsules.

Optimization of Laboratory Preparation of the Emulsified Bioasphalt with Two Emulsifiers

Abstract The goal of this study was to optimize emulsified bioasphalt (a mix of bio-oil and petroleum asphalt) performance by investigating the effects of various bio-oil dosages and emulsifier types and dosages. A colloid mill with high-speed rotation was used to emulsify the bioasphalt at 100°C. The single variable theory of analysis was adopted to analyze the influence of bio-oil and emulsifier on the performance of emulsified bioasphalt. Two types of emulsifiers were used: Shanghai Yuanrong-type (SY-type) and Meadwestvaco-type (MD-type). Five bio-oil contents were selected to produce the bioasphalt: 10, 15, 20, 25, and 30 %. Five emulsifier dosages were applied for the bioasphalt emulsification: 2.0, 2.5, 3.0, 3.5, and 4.0 %. Properties were evaluated by a series of tests, including the remaining amount of evaporation residue, penetration, softening point, ductility, viscosity, and storage stability. Based upon these test results, a 55:45 water-oil ratio, 15–20 % bio-oil content, and 3.5 % SY-type or 3.0 % MD-type emulsifier dosage is recommended.