Core-shell Emulsion Research Articles

Tunable microstructure of polyacrylate/ZnO nanorods composite emulsion and its film-forming properties

Polyacrylate/ZnO nanorods core-shell emulsion was prepared via emulsion polymerization for the first time. The distribution of ZnO nanorods in and out of the polyacrylate latex was achieved by adjusting the mass ratio of the non-ionic and anionic surfactants. The effects of surfactant composition on the distribution of ZnO nanorods in and out of polyacrylate latex, and the effect of composite latex microstructure on the properties of composite films were investigated in detail. The results showed that when the mass ratio of non-ionic and anionic surfactants was 0:1, the ZnO nanorods were located outside of the polyacrylate latex through electrostatic interaction with only anionic surfactants, forming polyacrylate@ZnO latex. Moreover, the ZnO nanorods can be uniformly dispersed in the composite film, and the tensile strength of the composite film was optimal. When the mass ratio of non-ionic and anionic surfactants was 1.5:1, all ZnO nanorods were encapsulated inside the polyacrylate latex to form ZnO@polyacrylate latex, the elongation at break and water resistance of the composite film were the best. When the mass ratio of non-ionic and anionic surfactants was 2:1, the agglomeration of ZnO nanorods in the composite film resulted in an increase in free volume, and the water vapor permeability of the composite film was optimal. Therefore, the microstructure of the hybrid latex can affect the macroscopic properties of the composite film. This study is expected to provide a theoretical basis for the structural design and performance optimization of the nanocomposite.

Synthesis of core-shell fluorinated acrylate copolymers and its application as finishing agent for textile

Core-shell fluorinated acrylate copolymers emulsion was thus synthesized via the core-shell emulsion polymerization with the fluorinated monomers and acrylic monomers as the main raw materials and its properties were studied. PFMA, the fluorinated acrylate monomers, was synthesized by the esterification of perfluorooctanoyl chloride (PFOC) and hydroxypropyl methacrylate (HPMA). Then the core-shell fluorinated acrylate copolymers emulsion with a poly(MMA/BA/St) core and a poly(PFMA/MMA/BA) shell was synthesized via a starved semi-continuous core-shell emulsion polymerization method by using KPS and sodium bicarbonate as the initiator/buffer system and SDS/Twain 80 as the commixture emulsifier. Lastly, the synthesized copolymers was applied as textile finishing agent for cotton textile. The results of FT-IR and NMR indicated that PFMA had been synthesized as expected and effectively combined in the emulsion copolymerization. The GPC, zeta potential, TEM and DSC showed that the particles had uniform spherical core-shell structure with a diameter of 65-150 nm, and the distribution and emulsion stability was satisfactory. As XPS, FESEM and AFM shown, a hydrophobic structure which was similar to the structure of the lotus leaf were formed and the surface hydrophobicity of the films can be improved. Based on the analysis of DSC, thermal stabilities of the films were enhanced with the increase of fluorine content. Besides, FESEM of textiles showed that the surface of treated textiles were smooth and the edges were clear and visible, indicating significant improvement of the performance on water and oil repellent.

Properties and anticorrosion application of acrylic ester/epoxy core–shell emulsions: effects of epoxy value and crosslinking monomer

We first prepared an unsaturated epoxy resin ester (EM) by addition–esterification reaction with acrylic acid and then synthesized a series of acrylic ester/epoxy hybrid latexes (AE) with core–shell structure by semicontinuous emulsion polymerization method. The resultant AE emulsions are utilized as anticorrosion coatings of metals. The influences of EM content and crosslinking agent (PEG(400)DA) content on the physicochemical properties of the resultant emulsions and anticorrosion coatings of metals are investigated in detail. The AE emulsion displays better anticorrosion properties when it is prepared under the following conditions: the EM content of 30 wt% and PEG(400)DA content of 2.0 wt%. The relationships between the AE structure and anticorrosion properties of AE coatings are clearly illustrated. The corrosion resistances of AE coatings are not only depend on the crosslinking density, hydrophilic, and polarity among the AE chains, but also rely on the stability of the emulsion and the integrality and homogeneity of the coatings.

Preparation of fluorinated acrylate coating with high albedo and its cooling effect on asphalt mixture

With regard to the high-temperature diseases of the asphalt pavement, an environment-friendly emulsion with high albedo was considered for reducing the pavement temperature. Firstly, the effect of types and dosage of the fluorine monomer on properties of the emulsion was analysed through using the conventional emulsion polymerisation. Afterwards, by taking the fluorine monomer as the shell and acrylic monomers as the core, the stability and hydrophobicity of the emulsion with different core–shell ratios were studied with the seed emulsion polymerisation method employed. Based on the results derived from adding different types and dosage, TiO2 to the core–shell emulsion, it can be easily found that a better cooling effect can be obtained with the optimum amount being 10% when the particle size of TiO2 concentrates on 200–1000 nm. Finally, the reflectance spectrum of the coating and the cooling values of the asphalt specimen with the coating were tested, respectively. The results show that the albedo of the coating reaches 78.64% and the specimen temperature can be reduced by 13°C when the normal asphalt mixture approaches 60°C.

Preparation and performances of novel waterborne intumescent fire retardant coatings

Abstract The core–shell organic-modified montmorillonite (OMMT)/epoxy resin/styrene-acrylic emulsion was prepared using semi-continuous seeded emulsion polymerization and used as the binder of the waterborne intumescent fire retardant coating to improve the fire resistance performance and other basic performance such as water resistance performance, anti-yellowing and adhesion to substrates. Observation with transmission electron microscopy showed that core–shell emulsion had been synthesized successfully. The small angle X-ray diffraction results showed that OMMT was exfoliated and dispersed well in the emulsion within the appropriate content. Fire resistance test, thermal analysis, scanning electron microscopy (SEM), water resistance and yellowing resistance test respectively demonstrated that OMMT greatly improve fire resistance, thermal stability, water resistance and yellowing resistance performance with the addition of in the range of 1.5–2.5 wt.%. Moreover, the core–shell styrene-acrylic emulsion with 5 wt.% epoxy resin (E-44) improve the adhesion of the film to plywood (from 2 grade to 0 grade).

Synthesis and characterization of fluorine‐containing polyurethane–acrylate core–shell emulsion

ABSTRACTFluorinated polyurethane–acrylate (FPUA) hybrid emulsion was prepared by copolymerization of polyurethane, methyl methacrylate, and 1H,1H,2H,2H‐heptadecafluorooctyl acrylate (FA) via emulsion polymerization in the presence of a perfluoronated reactive surfactant. The polyurethane was synthesized from isophorone diisocyanate, poly(propylene glycol)‐1000, dimethylolpropionic acid, 1,4‐butanediol, and 2‐hydroxyethyl methylacrylate. The influence of the monomer on the surface properties, wetting behaviors, particle size, and viscosity of the emulsion was investigated. The mechanical properties of FPUA latex films were improved, and water absorption and contact angle were improved with the addition of methyl methacrylate and FA. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43357.

Synthesis and characterization of monodisperse emulsion copolymer

Monodisperse emulsion copolymer was synthesized by semi-continuous core-shell emulsion polymerization of styrene, butyl acrylate and γ-methacryloxypropyl trimethoxy silane(KH570). The emulsion particles size and its polydispersion were measured by dynamic light scattering(DLS). The properties of emulsion copolymer were characterized by differential scanning calorimetry(DSC), thermogravimetric analysis(TGA) and measurement of contact angle. The particle morphology was observed under a transmission electron microscope(TEM) and atomic force microscopy(AFM). The results indicate that emulsion nanoparticles containing silicon possess core-shell structures and narrow polydispersity(PDI≤0.08). The thermal stability and hydrophobicity of emulsion copolymer were improved with KH570 introduced into the system.

Core–shell emulsion polymerization of styrene and butyl acrylate in the presence of polymerizable emulsifier

ABSTRACTA series of core–shell polymeric particles of styrene butyl acrylate were successfully prepared in the presence of polymerizable emulsifier. The compositions of the emulsions obtained were confirmed by Fourier transformed infrared spectrometry. Latexes and emulsion films were characterized by transmission electron microscopy and scanning electron microscopy, respectively. The thermostability of emulsion films was characterized by thermogravimetric analysis. The results showed that the existence of polymerizable emulsifier could enhance the solid content of the emulsion and the monomer conversion. The optimum mass ratio of polymerizable emulsifier to traditional emulsifier was 1:1, and the polymerizable emulsifier can participate in the emulsion polymerization perfectly. An emulsion with reverse core–shell particles exhibited better hydrophobic properties and thermostability than one with traditional core–shell particles. The film formed by the emulsion with reverse core–shell particles had lower water absorption, and it could be used in the fields of coatings, surface sizing agents, and spinning. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2016,133, 43091.

Progress of Polyurethane/Acrylate Core-Shell Hybrid Emulsion

Polyurethane/acrylate(PUA) core-shell hybrid emulsion as the binder has been widely used into inks recently and the different modifications for it with element reagents and resin reagents are displayed in the article as well. Moreover, the relationship between structure and properties and application of PUA core-shell hybrid emulsion in inks are also put forward in detail. Ultimately, the novel modified materials, rational molecule design and synthetic process were prospected in this review.

Water-Resistance Material from Fibers and Acrylic Emulsion Terpolymer

Styrene (SM), methyl methacrylate (MMA), and butyl acrylate (BA) were used to synthesize a polyacrylic emulsion by core-shell emulsion polymerization. The solid content of the emulsion reached 40% using reasonable reactive emulsifier contents and feeding modes. Then, two kinds of fibers (recovered and hardwood fiber) were respectively dispersed, coated, and dried with emulsion. Finally, fiber-based water-resistant material was successfully fabricated. The experimental results showed that under the conditions of a mass ratio of polyacrylic emulsion to fiber of 2:1, the Cobb value of the material reached 7.1 g/m2 and 10.8 g/m2 respectively. Cobb value of recovered fiber material was more stable than hardwood fiber, and stayed in a lower variation scope on the whole. Using scanning electron microscopy (SEM) to observe the surface morphology of products. The SEM results proved that, the polyacrylic emulsion filled the gaps between fibers, decreased the porous structure. This filling effect led to a continuous structure, and kept the water from infiltrating inside of the material. On the other hand, for the short fiber in recovered fiber material arranged closer, the water resistance of the material was further enhanced.

Silicylacrylate copolymer core–shell emulsion for humidity coatings

• Silicylacrylate copolymer core–shell emulsion particles were prepared. • Improving the water and stain resistance of coatings. • The formation mechanism of core–shell structure was given. • The humidity controlling coatings show excellent humidity-sensitive property. Using silicylacrylate (SPMA: 3-(trimethoxysilyl)propyl methacrylate) and acrylic acid as functional monomers, silicylacrylate copolymer core–shell emulsion (SiA-CSE) was prepared by emulsion polymerization. The relationships between stability of SiA-CSE and contents of SPMA, emulsifier, initiator and copolymerization temperature were investigated. Moreover, the structure of SiA-CSE was characterized by FTIR, TEM and TGA techniques. The SiA-CSE was applied to prepare the silicylacrylate copolymer humidity coatings (SiA-CSE-C) by compositing with pigments and porous fillers. Based on measuring the basic performance of copolymer emulsion film and SiA-CSE coatings, the humidifying function of SiA-CSE coatings was investigated. In conclusion, SPMA could improve the adhesion of SiA-CSE film and water resistance of the coatings. The obtained coatings showed excellent humidity-sensitivity and humidity retention, which could be used as the interior walls coatings in the building.

Water-Resistant Material from Recovered Fibers and Acrylic Emulsion Terpolymer

Styrene (SM), methyl methacrylate (MMA), and butyl acrylate (BA) were used to synthesize a polyacrylic emulsion by core-shell emulsion polymerization. The solid content of the emulsion reached 40% using reasonable reactive emulsifier contents and feeding modes. Then, the emulsion and a fiber were dispersed, coated, and dried together. Finally, fiber-based water-resistant material was successfully fabricated. The experimental results showed that under the conditions of a monomer mass ratio of 1:1:1 and a mass ratio of polyacrylic emulsion to fiber of 2:1, the Cobb value of the material reached 5.0 g/m2. The tensile strength, elongation, and breaking length were 7.4225 kN/m, 1.0%, and 11.706 km, respectively. Using scanning electron microscopy (SEM) to analyze the surface morphology and internal structure of products, the reasons for the high water resistance of fiber-based material was due to the bonding and filling effects of the polyacrylic emulsion on the fibers. For tightly bound fibers, the porous structures formed in fiber-based boards were reduced. On the other hand, the polyacrylic emulsion filled the gaps between fibers. This filling effect led to a continuous structure, and the water resistance of the material was further enhanced.

コアシェル構造を持つカチオン性塩化ビニルエマルションによるシリカ系塗料の流動性改善のメカニズム

インクジェット適性を付与するシリカ系塗料にはポリビニルアルコールが含まれている。これは，塗料の保水性向上，紙へのインクジェット適性付与及びコート層強度向上に貢献しているが，塗料の流動性悪化による塗工適性への悪影響や塗料の高濃度化ができないことによる乾燥負荷増大の問題があった。この課題を解決すべく検討した結果，コアシェル構造を有するカチオン性塩化ビニルエマルションでシリカ系塗工液のポリビニルアルコールの一部を置換することで，塗料の流動性の改善に加え，コート層の耐摩耗性の向上が認められた。本稿では，カチオン性塩化ビニルアクリルエマルションの，塗料の流動性とコート層強度に及ぼす効果とそのメカニズムについて報告する。

The Study of nano-SiO<sub>2</sub>/Polyacrylate Core-Shell Hybrid Emulsions

nano-SiO2 modified core-shell polyacrylate composite emulsion was synthesized by seeded semi-continuous starved pre-emulsion polymerization and sol-gel technique. The influence of 3-methacryloxypropyltrimethoxysilane(KH-570), tetraethoxysilane(TEOS) on the properties of emulsion and film were studied. The SiO2/silicone polyacrylate composite latex and the resultant films were characterized by fourier transform infrared spectroscopy(FT-IR), differential scanning calorimeter(DSC), thermogravimetric analysis(TGA), water contact angle goniometer (WCAG). The results showed that organic silicon and nano-SiO2 were effectively grafted to the polyacrylate molecular chain. We can observed there are two glass transition temperatures (Tg) in the DSC curve. The water contact angle (WCA) on the PAE film and SSPAE film separately attained 62.5°and 85.5°.

Magnetically transportable core-shell emulsion droplets with an antioxidative all-organic paramagnetic liquid shell.

Magnetically-transportable core-shell emulsion droplets with an antioxidative all-organic paramagnetic liquid shell [Nitroxide Radical Liquid (NRL) microcapsules] were demonstrated. We successfully fabricated stable NRL microcapsules with microfluidic devices. The NRL microcapsules are magnetically transportable and are likely to protect the inner phase from oxidants. Consequently, the NRL microcapsules can serve as a flexible antioxidative magnetic carrier for nanoliter cargoes.

Preparation and Application of a Leather Finish with Core-Shell Structure

The core-shell acrylic resin emulsion is prepared by seed polymerization technology, with styrene, methyl methacrylate, acrylonitrile as monomer, butyl acrylate, methyl methacrylate, acrylic acid as shell monomer, and the of nanoTiO2 is introducted in shell emulsion. Infrared spectroscopy were used to characterize the structure of the prepared coating agent. The preparation of TiO2/acrylic resin emulsion for leather finishing agent, and discusses its influence on the leather properties. The results show that the synthetic finishing agents for dyeing after the fatliquoring leather finishing, good finishing effect can be obtained.

Stable acrylate/triethoxyvinylsilane (VTES) core–shell emulsion with low surface tension made by modified micro-emulsion polymerization: Effect of different mass ratio of MMA/BA in the core and shell

Stable acrylate/triethoxyvinylsilane (VTES) core–shell emulsion with different mass ratio of MMA/BA in the core and shell was prepared via a modified micro-emulsion polymerization process. The chemical composition and core–shell structure were investigated by Fourier transform infrared (FTIR) spectrometry, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM), respectively. Effect of MMA/BA mass ratio in the core and shell on the film-forming ability, surface tension of latex was also studied. Finally, water absorption and thermal stability of the latex films were characterized. It was found that the surface tension of emulsion can be reduced to 32.9N/m when the MMA/BA mass ratio in the shell is 6/4. The water absorption of the latex film could be improved at a proper mass ratio of MMA/BA in core and shell, but adjusting the mass ratio of MMA/BA in the shell has little influence on the thermal stability of latex film. This work provides a method of preparing environment-friendly latex with low surface tension and excellent water resistance for coating applications by regulating the mass ratio of monomers in a modified micro-emulsion polymerization process.

Preparation of starch-based styrene acrylate emulsion used as surface-treatment agent for decorative base paper

Abstract A series of cationic starch (CS-8)-based styrene (St) acrylate latex preparations was prepared by the core-shell emulsion polymerization method. The latex was used in the surface-treatment of decorative base papers, for good printability and absorbability. CS-8, which has a low relative viscosity, was used as the emulsifier and dispersant. The influencing factors (dosage of CS-8 as well as the kinds and dosages of functional monomers) were studied and the optimal conditions were achieved. Then, the products were characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR), laser particle size analysis and particle charge detection. The results showed that the excellent performance and good surface-treatment effects of the St acrylate emulsion (SAE) were achieved when the reaction conditions were as follows: 10 wt% starch, 2 wt% methacryloyloxyethyltrimethyl ammonium chloride (DMC) as the cationic monomer and 20 wt% ethyl acrylate (EA) as the acrylate monomer. Under the optimal conditions, the latex particle size was around 160 nm, the latex viscosity was 10 mPa·s and the latex charge density was 0.60 mmol·l-1. The printability of the decorative base paper was significantly improved and the absorbability of the paper sheet was maintained. The surface-treatment effect of the cationic starch-based SAE was superior to that of commercial polyurethane (PU).

Organosilicone modified styrene-acrylic latex: preparation and application

In this paper, organosilicone modified styrene-acrylic (OSA) latexes for waterproof coating were synthesized through core–shell emulsion polymerization. The influence of emulsifier type and dosage on the size, size distribution and morphology of the latex was systematically investigated. The water absorbance and thermal decomposition behavior and the mechanical properties of the waterproof coating depending on the organosilicone introduced on the latex shell were also studied. Transmission electron microscopy and dynamic light scattering results indicated that the particles had a regular spherical morphology with different diameters and distributions. Thermal gravimetric analysis results revealed that the thermal stability of the latex films was improved with the introduction of organosilicone. The waterproof property of the OSA latex film was obviously increased as compared to that of the styrene-acrylic latex film. The tensile strength and fracture elongation of the elastic waterproof building coating made of the OSA latex and cement powder were significantly greater than that made of the styrene-acrylic latex and cement powder.

Waterborne polyurethane-acrylic copolymers crosslinked core–shell nanoparticles for humidity-sensitive coatings

A novel crosslinked core–shell emulsion of waterborne polyurethane-acrylic copolymers (PUA) was successfully synthesized by emulsion polymerization. The average particle size of the PUA particle was approximately 130nm and its core–shell morphology was proved with transmission electron microscopy (TEM) and dynamic light scattering (DLS), whose structure was also confirmed by FT-IR and TGA. PUA was applied to prepare the humidity controlling coatings (PUA-C) by compositing with pigments and porous fillers. The structure and properties of humidity controlling coatings were investigated, with particular attention to the effects of the humidity controlling. The surface morphology of the PUA-C was observed by scanning electron microscope (SEM). The humidity controlling coatings showed excellent properties of humidity sensitivity and humidity retention.