Direct Emulsification Research Articles

The Effect of Weighting Materials on the Rheological Properties of Iraqi and Commercial Bentonite in Direct Emulsion

Numerous drilling additives and materials are used continuously because they are necessary to support and give the required properties of the drilling fluid so that to ensure the stability of the borehole. This paper aspires to evaluate the rheological properties of bentonite (montmorillonite) Trefawey as an alternative to using commercial bentonite. Monitoring and evaluating of the rheological and filtration properties were prepared. This exertion aims to focus on the effect of hematite, and barite on the rheological properties of the three aforementioned bentonite types. An improvement in the rheological properties of bentonite (montmorillonite). Trefawey was observed after adding the previous heavy materials. Hematite has by some means better ability to improve rheological properties compared to other heavy materials. The emulsifying agent used was Carboxyl Methyl Cellulose (HOCH2COONA), as it has provided excellent results parallel to the lignite. The rheological properties of bentonite (montmorillonite) Trefawey are enhanced by doubling the amount of carboxyl methyl cellulose (HOCH2COONA). The results have proved that the use of weighting materials and emulsifying agent affected the rheological properties of bentonite (montmorillonite) Trefawey in a direct emulsion. The results have shown that it is more appropriate to use carboxyl methyl cellulose as an emulsifying agent to prepare a direct emulsion than bentonite (montmorillonite) Trefawey due to its excellent effect in improving the rheological properties of bentonite (montmorillonite) Trefawey. And it can be said that this effort has succeeded in studying two effects simultaneously. In other words, both heavy substances and emulsifying agent have effects on bentonite (montmorillonite) Trefawey, in order to obtain a stable emulsion and a clearer view of the behavior of Iraqi bentonite. The above effort has focused on making bentonite (montmorillonite) Trefawey suitable for the nature of geological layers such as oil shale, limestone and sandstone. This means preparing drilling fluid using bentonite (montmorillonite) Trefawey to drill the above structures. The study has concluded that it is better to use bentonite (montmorillonite) Trefawey in preparing direct oil emulsions as a stable and successful alternative of imported bentonite.

Preparation of Thymus vulgaris Essential Oil Microcapsules by Complex Coacervation and Direct Emulsion: Synthesis, Characterization and Controlled Release Properties

This study examines the preparation and characterization of Thymus vulgaris (L.) essential oil (TEO) microcapsules obtained by complex coacervation and direct emulsion techniques. The extraction yield of TEO for this study was 1.64% with Thymol (56.38%) and carvacrol (23.84%) as dominant components. The synthesis protocol was conducted with different polymer/polysaccharide mass ratios, essential oils quantities and cross-linking agent. Optical microscopy images of the microcapsules show spherical shape for particles of different diameters ranging from 5 to 50 μm. SEM analysis shows that the best results were obtained with a polymers ratio of 7%:8% and formaldehyde as cross-linking agent. The encapsulation yield is 65.67 and 98% for complex coacervation and direct emulsion, respectively. The encapsulation efficiency reveals that the amount of oxygenated monoterpenes encapsulated represents 78.34–74.31% of the total coated amount. Monoterpenes hydrocarbons represent 16.03–19.77%, followed by sesquiterpenes hydrocarbons at 3.7–4.2% for complex coacervation and direct emulsion, respectively. This result confirms that encapsulation efficiency can be related to the polarity of each TEO component. All results support the success of TEO encapsulation in terms of storage, protection and release, with lower thermal stability and faster TEO release kinetic for direct emulsion encapsulation. This result contrasts with complex coacervation, which provides a slower release profile and better thermal stability.

Influence of emulsification mode, stirring speed and volume on ibuprofen-loaded PLGA microparticles

Microparticles based on biodegradable synthetic lactic acid and glycolic acid copolymer (PLGA) were successfully prepared by the solvent evaporation method. Ibuprofen was chosen as the model drug. Various formulation and process parameters have been used to prepare each sample with emphasis on size reduction. The effect of the emulsification method (direct emulsification or emulsification using an ULTRA-TURRAX or a NE-1000 dispenser), the volume of the aqueous phase (200, 800 ml) and the stirring speed of the emulsion system (600, 1000 rpm) on the characteristic properties of microparticles, such as encapsulation efficiency, drug loading and particle morphology, was observed. The resulting microparticles were evaluated by optical microscopy or laser diffraction and the dissolution test was performed. It was found that the sample prepared by direct emulsification with 800 ml of an aqueous phase at 600 rpm provided the most favorable results, meanwhile the emulsification pre-step using a homogenizer caused promising particle size reduction. Gradual emulsification was evaluated as inapplicable due to great losses.

Development of Energy-resource-efficient Equipment and Technologies of Environmentally Safe Microwave Processing of Oil Sludges


 
 
 the results of the analysis of scientific papers and patent elaboration of the existing methods and technologies for the separation of water-oil emulsions made it possible to implement energy-efficient processes of microwave exposure to hydrocarbon- containing media. Based on the analysis of existing mathematical models of the direct and reverse oil-water emulsions structure and evaluation of the behavior of oil-water emulsions in the microwave field, a mathematical model of the interaction of microwave energy with oil-water emulsions 1 has been developed. The use of this model allows for the identification of the most effective parameters of the microwave exposure for phase separation with different compositions and dielectric parameters of emulsions. Computational experiments have been carried out to identify the dependence of the binding energy of water molecules and different grades of oil on the physicochemical properties of the emulsion and the technological factors of the sludge processing. An experimental installation of microwave sludge processing has been developed and manufactured, which allows determining the adequacy of the developed model.
 Keywords: microwave processing, oil sludge, phase separation
 
 

Surface functionalization of poly(vinylidene fluoride) membrane by radiation‐induced emulsion polymerization of hydroxyethyl acrylates in an aqueous medium

AbstractDecades ago, surface modification of poly(vinylidene fluoride) (PVDF) membrane became an essential subject. The change is mainly to enhance the hydrophilicity properties of the membrane in order to increase the adsorption capacity, thus making as a novel adsorbent. This study aims to used radiation‐induced polymerization and compares the final properties of PVDF grafted hydroxyethyl acrylates (HEA) prepare by two different approaches. The PVDF‐grafted‐HEA has achieved either direct polymerization or emulsion polymerization. Tween‐20 has been used as a surfactant in emulsion polymerization. The final PVDF‐grafted poly‐HEA was analyzed using several different instruments to observe the changes in terms of morphological structure, topography properties, thermal stability, mechanical strength, and hydrophilicity. Significant differences were seen in morphology and contact angles properties. By emulsion polymerization, poly‐HEA grafted in the shape of micelles compare to by direct polymerization shown a thin homogenous layer. Thus, the surface roughness of PVDF by emulsion is higher lead to higher contact angles. Even though both approaches demonstrate significant changes in the physicochemical properties of the PVDF membrane, it is revealed that radiation‐induced direct polymerization approaches could achieve a hydrophilic PVDF‐grafted HEA.

Application of optical spectroscopy for investigation of synthesis of hydrogen and nanoparticles in electric discharge in liquid-phase media

In this work, a low-temperature plasma initiated in liquid media between electrodes has been shown to be able to decompose hydrogen containing organic molecules resulting in obtaining gaseous products with volume part of hydrogen higher than 90% as well as nanoparticles of discharge electrodes material. As feedstocks, organic compounds (alcohols, esters) as well as direct water-hydrocarbon emulsions obtained by ultrasonic treatment are used. It is shown that hydrogen productivity from emulsions is not less than that from individual substances.The method of optical spectroscopy was used to confirm the formation of atomic hydrogen in the reactions of plasma decomposition of liquids and to study of plasma characteristics in this process.The measurement of the amount of the gas mixture and nanosized products formed during the decomposition of organic liquids shows that the output is highly dependent on the discharge current, and also on the volume of the discharge, which can vary depending on the distance between the electrodes in the reaction chamber.The dependence of the glow intensity of the discharge on its parameters and materials of the discharge electrodes is shown. In current experiments, the discharge current is from 4A to 8A, the discharge voltage depending on the type of liquid is 30–45 V.It has been found that the simultaneous excitation of an electric arc discharge and acoustic cavitation in water, organic liquids and their mixtures is an effective method for the synthesis of gaseous hydrogen and various types of solid nanoparticles.Ultrasonic action above the cavitation threshold intensifies heat and mass transfer processes in the treated medium, promotes the homogenization of dispersed systems, activation of the surface of solid particles, the appearance of defects in crystal structures due to dislocations and the formation of vacancy complexes, in combination with an electric discharge, which contributes to the appearance of an ionized state of matter (plasma); such an effect is capable of decomposing complex molecules to an atomic state with subsequent recombination and the formation of simple molecules.It has been shown that this is an energetically favorable method for the conversion of liquid-phase compounds, stimulated by thermally nonequilibrium plasma, which produces active particles – excited molecules and radicals, which makes it possible to initiate chain reactions, including energetically branched ones, and thereby significantly accelerate the process of liquid conversion and decrease the temperature allowing for such conversion.Synthesized metal and metal oxide nanoparticles from electrode materials possess activated surface due to the ultrasonic cavitation and can be subsequently used as functional nanoparticles, e.g. nanoparticles with antibacterial properties as well as components of polymer composite materials.

Concentrated salt-resistant emulsions of the “oil in water” type used for the development of oil and gas wells

Currently, water-based and hydrocarbon-based oil and gas well silencing fluids are widely used. The most promising liquids for silencing and developing wells are direct emulsions, whose viscosity can be regulated by changing the concentration of the “oil” phase. Urgent task is to develop polymer-free structured emulsion compositions for developing and silencing low-temperature oil and gas wells that are stable when the water phase is saturated with sodium or potassium chlorides. For use in protected areas, the developed formulations should use vegetable oils and esters based on them as the oil phase, along with hydrocarbons.

Preparation, stabilization, and characterization of polyisobutylene aqueous suspension

Aqueous suspension of polyisobutylene (PIB) was stabilized via application of anionic surfactant of sodium lauryl sulfate (SLS) and co-surfactants of stearyl and cetyl alcohols. Suspensions were produced via the so-called direct emulsification technique. Some characterization tests including zeta potential, particle size, turbidity, conductivity, and rheology measurements were demonstrated to analyze the stability of produced suspensions. Turbidity and particle size measurements showed that just some of the samples were stable while the others exhibited partial aggregation of particles. The characterization tests showed that the sample contained 2 g of polyisobutylene, 0.45 g SLS, 0.175 g stearyl, and 0.263 g cetyl alcohols, i.e., co-surfactant ratio of 0.66, in 80 mL of water exhibited appropriate stability. Possession of high zeta potential of − 93.65 mV, conductivity of 570 mS/cm, an average particle size of 10 μm, and good rheological behavior besides the stable appearance revealed that this sample did not undergo agglomeration, flocculation, or any phase separation.

Novel Self-Assembled Polycaprolactone–Lipid Hybrid Nanoparticles Enhance the Antibacterial Activity of Ciprofloxacin

Ciprofloxacin (CIP), a widely used antibiotic, is a poor biopharmaceutical resulting in low bioavailability. We optimized a CIP polymer-lipid hybrid nanoparticle (CIP-PLN) delivery system to enhance its biopharmaceutical attributes and the overall therapeutic performance. CIP-PLN formulations were prepared by a direct emulsification-solvent-evaporation method. Varying the type and ratio of lipid was tried to optimize a CIP-PLN formulation. All the prepared formulations were evaluated for their particle size, polydispersity index, zeta potential, physical stability, and drug entrapment efficiency. The drug in vitro release profile was also studied. Antibacterial activities were tested by the agar diffusion method for all CIP-PLN formulations against an Escherichia coli clinical bacterial isolate (EC04). CIP-PLN formulations showed average sizes in the range of 133.9 ± 1.7 nm to 217.1 ± 0.8 nm, exhibiting high size uniformity as indicated by polydispersity indices lower than 0.25. The entrapment efficiency was close to 80% for all formulations. The differential scanning calorimetry (DSC) thermograms indicated the existence of CIP in the amorphous state in all PLN formulations. Fourier transform infrared spectra indicated deep incorporation of molecular CIP within the polymer matrix. The release profile of CIP from PLN formulas showed a uniform prolonged drug profile, extended for a week from most formulations with a zero-order kinetics. The antibacterial activity of CIP-PLN formulations showed significantly higher antibacterial activity only with F4 containing lecithin as the lipid component. In conclusion, we successfully optimized a CIP-PLN formulation with a low nanoparticle size in a close range, high percentage of entrapment efficiency and drug loading, uniform prolonged release rate, and higher antibacterial activity against the EC04 clinical isolate.

Optimized Polyethylene Glycolylated Polymer-Lipid Hybrid Nanoparticles as a Potential Breast Cancer Treatment.

Purpose: The aim of this work is to optimize a polyethylene glycolated (PEGylated) polymer–lipid hybrid nanoparticulate system for the delivery of anastrozole (ANS) to enhance its biopharmaceutical attributes and overall efficacy. Methods: ANS loaded PEGylated polymer–lipid hybrid nanoparticles (PLNPs) were prepared by a direct emulsification solvent evaporation method. The physical incorporation of PEG was optimized using variable ratios. The produced particles were evaluated to discern their particle size and shape, zeta-potential, entrapment efficiency, and physical stability. The drug-release profiles were studied, and the kinetic model was analyzed. The anticancer activity of the ANS PLNPs on estrogen-positive breast cancer cell lines was determined using flow cytometry. Results: The prepared ANS-PLNPs showed particle sizes in the range of 193.6 ± 2.9 to 218.2 ± 1.9 nm, with good particle size uniformity (i.e., poly-dispersity index of around 0.1). Furthermore, they exhibited relatively low zeta-potential values ranging from −0.50 ± 0.52 to 6.01 ± 4.74. The transmission electron microscopy images showed spherical shape of ANS-PLNPs and the compliance with the sizes were revealed by light scattering. The differential scanning calorimetry DSC patterns of the ANS PLNPs revealed a disappearance of the characteristic sharp melting peak of pure ANS, supporting the incorporation of the drug into the polymeric matrices of the nanoparticles. Flow cytometry showed the apoptosis of MCF-7 cell lines in the presence of ANS-PLNPs. Conclusion: PEGylated polymeric nanoparticles presented a stable encapsulated system with which to incorporate an anticancer drug (ANS) with a high percentage of entrapment efficiency (around 80%), good size uniformity, and induction of apoptosis in MCF-7 cells.

Elaboration of double emulsion-based polymeric capsules for fragrance

We aim at encapsulating fragrances made of a variety of lipophilic species to slow down their diffusion. Our strategy is to develop capsules by polymerizing the water intermediate phase of an oil-in-water-in-oil double emulsion. In other terms, our system consists in a direct emulsion of fragrance (O1) in a water phase (W) containing monomer, initiator, and cross-linker. To obtain the double emulsion, this direct emulsion, stabilized by a hydrophilic surfactant, is itself dispersed in an external lipophilic solvent used in perfumery (O2) and stabilized by a lipophilic surfactant. Polymerization of the intermediate water phase aims at obtaining a 3D network. Differently from nowadays-proposed capsules, this strategy allows polymerization only taking place in the water phase rather in the phase containing the fragrance. Moreover, the obtained 3D network is supposed to play the role of an effective barrier limiting the diffusion of the inner lipophilic species towards either the external solvent or air. Such an approach implies the combination of a formulation step to elaborate the double emulsion using two antagonistic surfactants, a hydrophilic one and a lipophilic one, and of the polymerization of the intermediate phase. Insertion of the polymerizable species in the double emulsion shall not destabilize it. Some monomers exhibiting interfacial affinity and interfering with the formulation of the double emulsion have to be avoided. By varying the nature of the monomers and the cross-linker to monomer ratio, capsules with high encapsulation efficiencies and with various mechanical properties have been obtained.

Formulation of concentrated oil-in-water-in-oil double emulsions for fragrance encapsulation

We report the formulation of a concentrated double oil-in-water-in-oil (O/W/O) emulsion for fragrance encapsulation. As their water-in-oil-in-water homologous, these O/W/O emulsions, seldom described in literature, also require the use of two antagonist surfactants: a hydrophilic one (HS) to stabilize the fragrance-in-water droplets and a lipophilic one (LS) to stabilize the aqueous globules dispersed in oil, containing themselves the direct emulsion. An important issue in cosmetics is the necessity to adapt the formulation to each fragrance, so that a major progress would be the successful elaboration of an O/W/O emulsion insensitive to fragrance changes. In order to approach such a composition, two model fragrances composed of 10 and 13 molecules representative of the most used molecules in this domain were specially assembled for the study. The aim was to identify possible hydrophilic and lipophilic stabilizers leading to a double O/W/O emulsions and determine compositions able to encapsulate both fragrances. The double emulsion was prepared by a two-step process, allowing varying the double emulsion composition i.e the amount of both surfactants as well as the quantity of droplets inside the globules. By plotting “feasibility diagrams” we can propose a best composition shared by the two fragrances. Such a double emulsion is composed of 20 wt% of fragrance droplets with respect to the globule volume, 75 wt% of globules with respect to the total emulsion, 7.5 wt% of HS with respect to the intermediate aqueous phase and 10 wt% of LS with respect to external oil phase. The robustness of this optimized composition against molecule changes was tested using a third fragrance. Then the encapsulated efficiency was measured showing the high encapsulation rate (close to 99 %) of the selected system and a gas chromatography analysis of each molecule composing the complex fragrance showed no alteration of the encapsulated fragrance.

Cellular zirconia ceramics processed by direct emulsification

Highly porous zirconia ceramics for prospective use as separators in alkaline electrolysis cells have been processed by emulsification of paraffin in concentrated zirconia suspensions. Effects of processing parameters on porosity, cell size distribution, and pore interconnectivity are studied through Taguchi statistical design. The porosity of zirconia ceramics has shown a strong correlation with paraffin-to-suspension ratio employed in emulsification. High paraffin-to-suspension ratios combined with high gelatin content in the emulsion are beneficial for creating highly porous cellular materials with interconnected cell sizes. The attained microstructural features allow high percolation of ionic species in these highly porous ceramics after impregnation with aqueous electrolytes, facilitating charge transport within the liquid medium inside the ceramic bodies, as required for lower ohmic losses. This work provides guidelines for developing efficient ceramic separators for future use in alkaline electrolysis cells and other applications requiring thermally and chemically-stable ceramics with high and well-interconnected porosity.

Dual physically and chemically cross-linked polyelectrolyte nanohydrogels: Compositional and pH-dependent behavior studies

This study describes the composition-property relationship of a dual chemically and physically cross-linked nanohydrogel (NHG) containing a high concentration of hydrophilic pH-sensitive acrylic acid (AA). The physical and chemical cross-linking were incorporated using the aggregation of hydrophobic butyl acrylate (BA) and covalent bond of a bifunctional monomer (ethylene glycol dimethacrylate), respectively. Implementing a direct one-pot semi-batch emulsion polymerization technique in an acidic condition yielded monodispersed (PDI < 0.2) NHGs with a collapsed hydrodynamic radius of 60–100 nm. Titration studies revealed the significant effect of the chemical and physical cross-linking on the amounts of accessible carboxyl groups and their ionization behavior. These NHG dispersions displayed good colloidal stability over a wide pH and duration, the Donnan equilibrium is responsible for the observed swelling behavior of these NHGs.

Obtain and Application of Surface-active Substance on the Base of Products Refination of Cotton Seed Oil

The article the results of investigation on obtaining of surface-active substance -SAS on the waste cotton oil for drilling of wells and intensification of the flotation process are presented. The main component of new SAS are waste, cotton oil refinery and chemical plants. SAS have hudrophobization (waterproof) action on easy-swelling rocks (clays, argellites, alevrolits). Direct water emulsions obtained from reagents have low viscosity, high stability and low filtration index. There reagents have influence at drilling tools (that is they increase the life of drilling bits and diamond bits) [1, 2]. The study flotation enrichments of copper-molybdic ore is revealed characteristic foam-former and collector surface-active substances (NA-1) and is simulation one oily provided creation without minerals fields extraction of gold and color metals has been determined. Optimal conditions of the syntheses: ratio of main components, time of reaction, temperature and concentration have been determined. The comparison of new SAS with other foreing analogies was carried out. The main colloidal-chemical characteristic of synthesized SAS: surface activity, adsorption, viscosity, concentration of micelle- formation have been determined. Technology of obtain of anion surfaceactive substances from local organic raw material was elaborated, which by qualitative characteristics is a substitute of the import reagent collector and foam-former [4, 5]. Dependence on obtained product from the temperature of the process, time of reactions, ratio of initial components optimal concentration of NaOH was investigated. The foam forming ability of the new reagents in comparison with standard reagent T-92 was determined and it was shown that by best ability of forms destruction the methyl syloxane’s liquid and mineral oil have possessed.The intensifications of the process of flotation’s enrichment of copper-molybdic ore with using new obtain reagent NA-1 was offered.

Novel polymer surfactants based on the branched silatrane-containing polyesters and polyethers

Objectives. Biologically active polymeric surfactants are a new promising class of macromolecules that can find application in medicine, cosmetology, and agriculture. In this study, a number of new biologically active amphiphilic polymers based on branched silatrane-containing polyesters and polyethers were obtained, and their surface-active properties were investigated.Methods. The branched polymers were represented by polyethers and polyesters, obtained respectively via the anionic polymerization of 1,2-epoxypropanol or a combination of equilibrium polycondensation and ring opening polymerization. The polymers were modified with 3-isocyanopropylsilatrane and trimethylethoxysilane to obtain the amphiphilic compounds containing silatrane groups bonded to the polymer backbone by the urethane bond. The structure of the synthesized polymer silatranes was confirmed via nuclear magnetic resonance spectroscopy and gel permeation chromatography. The surface active properties of all the copolymers obtained were investigated in connection with their obvious amphiphilicity. In particular, the formation of micelles in aqueous solutions is such a property. The critical micelle concentrations were determined by a method of quenching the fluorescence of the polymers.Results. It was shown that the values of the critical micelle concentrations and the hydrophilic-lipophilic balance values of polymers determined by the Griffin equation correlate well with each other. A linear relationship between the hydrophilic-lipophilic balance and the critical micelle concentrations was established. At the same time, polyether-based polymers generally showed higher critical micelle concentrations than polyester-based polymers, although the hydrophilic-lipophilic balance values for polymers of different series, but with close degrees of substitution, were close. It was found that the use of all synthesized polymers as stabilizers of direct and reverse emulsions leads to an increase in the aggregative stability of both types of emulsions. The stability of emulsions depended both on the degree of substitution of peripheral hydroxyl groups of polymers by silatranes and on the molecular weight and structure of the branched block of polymers. The stability of direct emulsions increased for all polymers, while that of inverse emulsions decreased with an increasing degree of substitution of hydroxyl groups by silatranes. The increase of the branched block molecular weight led to an increase of droplet sizes for both direct and inverse emulsions. The smallest droplet size for direct and inverse emulsions was obtained using polymers with low molecular weight branched polyester blocks as surfactants.Conclusions. The results obtained prove the possibility of creating polymer surfactants containing silatrane groups. By varying the structure of the polymer, its molecular weight and the degree of substitution of peripheral functional groups, it is possible to obtain surfactants with desired surface properties.

Contrast-Variation Time-Resolved Small-Angle Neutron Scattering Analysis of Oil-Exchange Kinetics Between Oil-in-Water Emulsions Stabilized by Anionic Surfactants.

Contrast-variation time-resolved small-angle neutron scattering (CV-SANS) was used to examine oil-exchange kinetics between identical mixtures of hydrogenated/deuterated hexadecane emulsion systems. Oil-exchange rates were estimated by transforming recorded scattering profiles to a relaxation function and by fitting to exponential decay models. We find that the oil-exchange process was accelerated when the droplets were stabilized by anionic surfactants even at concentrations well below the surfactant critical micelle concentration. Moreover, the exchange rate was not significantly accelerated when surfactant micelles were present. This suggests that micellar-mediated transport mechanisms do not play the dominant role in these systems. Screening electrostatic repulsion by increasing the ionic strength of the medium also had a negligible effect on oil-exchange kinetics. In contrast, the use of oils with shorter alkane chain lengths (e.g., dodecane), having a higher solubility in water, significantly accelerated rates of oil transport between droplets. Oil-transport rates for hexadecane were also found to increase with temperature and to follow Arrhenius behavior. These results were rationalized as an increase in the droplet-collision frequency due to Brownian motion that results in direct oil transport without irreversible coalescence. Thus, primary mechanisms for oil exchange in insoluble anionic surfactant-stabilized emulsion systems are hypothesized to be through direct emulsion contact, reversible coalescence, and/or direct oil permeation through thin liquid films. CV-SANS is also demonstrated as a powerful technique for the study of transport kinetics in all kinds of emulsion systems.

New β-Cyclodextrin-Based Microcapsules for Textiles Uses

In this paper, a novel kind of microcapsules containing 2-ethoxynaphtalene (neroline) was successfully synthesized into polyurethane shells through the interfacial polycondensation of β-cyclodextrin with 4,4’-methylene (bisphenyl isocyanate) (MDI) in direct emulsion. The IR spectroscopy was used, on the one hand to confirm the success of polymerization reaction leading to the polyurethane shell formation, but on the other hand to check the encapsulation efficiency of fragrance that accounts for 40%. Microcapsules’ spherical shape and particle size distributions were revealed by means of optical microscopy, scanning electron microscopy (SEM) observation, and small-angle light scattering measurement. The impregnation of neroline-loaded microcapsules on polyamide knitted fabric was tested as an application method at a yield of around 74%. Adhesion of synthesized microcapsules to textile materials was evaluated through microscopic observations. The durability of the impregnation effect was tested by SEM and UV-visible spectroscopy. Washing fastness test of the impregnated polyamide knitting proved that the loaded microparticles retained their efficiency after more than 35 washing cycles.

A direct polymerization approach toward hindered phenol/polymer composite latex and its application for waterborne damping coating

The building of polymer composite particles in their confined colloidal-scale space is a highlighted topic, leading to advanced structure complexity and high performance in functional coating applications. Here, we demonstrate a direct emulsion polymerization (EP) approach to synthesize composite latex with hindered phenol (HP), a kind of functional small molecules, successfully loaded inside colloidal polymer particles. Monomer conversion as well as the evolution of droplet/particle size has been traced as a function of polymerization time. The results evidence the smooth running of the polymerization process with high HP loading in situ in the aqueous dispersion which could reach 30 phr. As-synthesized HP/polymer latex could be conveniently used for the formation of coating films. The films are unique for the greatly improved damping properties. With HP content of 30 phr, the effective damping temperature range can be broadened to 112 ℃, and the a maximum loss factor can rise to 2.7. The weak hydrogen bonding is found to be the key for the incorporation of HP with the polymer segments, and contributes to the dissipation of vibration energy in the films. Combined with the environmental benefits, waterborne composite latex here is of potential application for the building of green damping coating systems.

Multifunctional capsules with oil core and shells of SiO2 nanoparticles, nanodiamonds and polyelectrolyte layers with Fe3O4 nanoparticles

Multifunctional capsules based on Pickering emulsion and nanocomposite polyelectrolyte layers proved to be obtained and characterised. Direct emulsions were stabilised by mixture of nanodiamonds an...