Emulsion Polymerization Research Articles

Synthesis of novel acrylate emulsions and examination of their synergistic effects with nanocellulose on paper strengthening

AbstractWith the development of the “paper instead of plastic” trend, the investigation into high‐density, heavy‐weight paper has emerged as a point of interest in both academic and industrial realms. Regrettably, the paper‐strengthening agents that are commercially available fall short of meeting the strength specifications for such papers. To rectify this shortcoming, a water‐based acrylate paper‐strengthening agent (AA) was developed through radical emulsion polymerization. The most stable acrylate emulsion was obtained by amalgamating the anionic emulsifier allyloxyammonium oxymethyl sulfate nonylphenol ethoxy sulfate (DNS‐86) with the nonionic emulsifier nonylphenol polyoxyethylene ether (OP‐10) at a proportion of 1:0.6, with a dosage of 3%. Substituting the conventional strengthening agent (styrene‐butadiene latex) with the synthesized acrylate emulsion in wet‐end addition markedly improved the paper strength, registering a 54.8% increase to 29.4 MPa. The introduction of carboxylated cellulose nanofibers (C‐CNF) further bolstered the mechanical properties of the paper, achieving a tensile strength of 41.44 MPa and an elongation at a break of 3.55%. These results underscore the efficacy of acrylate as a paper‐strengthening agent and the crucial role of C‐CNF in enhancing the structural integrity of paper materials.

Synthesis of ZnO/Poly(Styrene‐co‐Methacrylic Acid) Hybrid Polymer Particles for Enhanced UV‐Visible Photodegradation of Methylene Blue

AbstractIn this study, a series of submicron‐sized functional polymer particles poly(Sty‐co‐MAA) with variable methacrylic acid (MAA) content were prepared by soap‐free emulsion polymerization of styrene (Sty), methacrylic acid (MAA), and ethylene glycol dimethacrylate (EGDMA). The number‐average diameters of polymer particles (Dn) were in the range of 0.11 to 0.19 μm. A decrease in particle size was observed with increasing the molar ratio of MAA comonomer in the recipe. ZnO/poly(Sty‐co‐MAA) hybrid polymer particles were prepared by seeded emulsion copolymerization in presence of zinc oxide nanoparticles (ZnO NPs) as seed particles synthesized using Citrus lemon aqueous leaf extract. Scanning electron microscopy (SEM), transmission electron microsphere (TEM), X‐Ray Diffraction (XRD), and Fourier transformed infra‐red (FT‐IR) analysis were performed to characterize polymer particles. The crystalline size of ZnO NPs and ZnO/poly(Sty‐co‐MAA) hybrid polymer particles calculated from XRD analysis were 20.75 and 29.85 nm, respectively. These hybrid polymer particles were applied as photocatalyst in the photodegradation of methylene blue (MB) dye under UV irradiation, which showed high catalytic activity with degradation efficiency of 85.70 % at room temperature compared to bare ZnO NPs.

Maltodextrin polymer nanospheres as a filtrate reducer for filtration control in water-based drilling fluids

With the development of deep and ultra-deep wells, there is a need to enhance the rheological and filtration properties of water-based drilling fluids under high temperature and salinity conditions. In this study, maltodextrin polymer nanospheres (MDPN) were synthesized through cross-linking maltodextrin and methylene bisacrylamide (MBA) via inverse emulsion polymerization. Then, the polymer MDPN-DAN was synthesized via aqueous solution polymerization, using maltodextrin polymer nanospheres, N, N-dimethylacrylamide (DMAA), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), and N-vinylpyrrolidone (NVP) as raw materials. Structural characterization confirmed the successful synthesis of the polymer MDPM-DAN, with a median particle size of 234.4 nm. Thermogravimetric analysis revealed a thermal decomposition temperature of 242 °C for MDPM-DAN. This polymer demonstrated excellent settling stability at 220 °C in high-temperature and weakly alkaline environments. Rheological assessments demonstrated a 754 % enhancement in the drilling fluid’s rheological properties when MDPM-DAN was added compared to the base mud. MDPM-DAN demonstrated significant reduction in filtration loss, with polymer mud aged at 220 °C showing only 5.6 mL of loss, and polymer mud aged at 220 °C with 15 wt% NaCl exhibiting 8.9 mL loss. The filtration loss reduction mechanism elucidated that MDPM-DAN could adsorb onto bentonite particles via hydrogen bonds, while nanoparticles filled the micropores of the filter cake, promoting the formation of a dense filter cake. Furthermore, plugging experiments showcased MDPM-DAN’s ability to block nano-pore throats, with the molecular chain’s amide groups reinforcing the plugging through hydrogen bonding with rocks, while bentonite coats the micro-pore throats.

Crystallization-Driven Controlled 2D Self-Assemblies via Aqueous RAFT Emulsion Polymerization.

Aqueous emulsion polymerization is a robust technique for preparing nanoparticles of block copolymers; however, it typically yields spherical nanoassemblies. The scale preparation of nanoassemblies with nonspherical high-order morphologies is a challenge, particularly 2D core-shell nanosheets. In this study, the polymerization-induced self-assembly (PISA) and crystallization-driven self-assembly (CDSA) are combined to demonstrate the preparation of 2D nanosheets and their aggregates via aqueous reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization. First, the crucial crystallizable component for CDSA, hydroxyethyl methacrylate polycaprolactone (HPCL) macromonomer is synthesized by ring opening polymerization (ROP). Subsequently, the RAFT emulsion polymerization of HPCL is conducted to generate crystallizable nanomicelles by a grafting-through approach. This PISA process simultaneously prepared spherical latices and bottlebrush block copolymers comprising poly(N',N'-dimethylacrylamide)-block-poly(hydroxyethyl methacrylate polycaprolactone) (PDMA-b-PHPCL). The latexes are now served as seeds for inducing the formation of 2D hexagonal nanosheets, bundle-shaped and flower-like aggregation via the CDSA of PHPCL segments and unreacted HPCL during cooling. Electron microscope analysis trace the morphology evolution of these 2D nanoparticles and reveal that an appropriate crystallized component of PHPCL blocks play a pivotal role in forming a hierarchical structure. This work demonstrates significant potential for large-scale production of 2D nanoassemblies through RAFT emulsion polymerization.

Sensitive dual-channel lateral flow immunoassay tagged with high brightness latex microsphere for simultaneous detection of respiratory viral antigens

Respiratory infectious diseases pose a serious threat to human health worldwide. Timely diagnosis is crucial for effective clinical management and infection control. Herein, we developed a dual-channel lateral flow immunoassay (DC-LFIA) for simultaneous sensitive detection of influenza A virus (IAV) and respiratory syncytial virus (RSV) nucleoprotein (NP) antigens. The high brightness latex microspheres (HB-LMs) exhibiting typical absorption peak at 540 nm with uniform size and excellent optical stability, were prepared by a simple surfactant-free emulsion polymerization by mixing Sudan red, which overcame the complexity and color instability met for traditional synthesis methods. After affinity evaluation, two antibody pairs have good affinity for IAV NP and RSV NP were separately identified. Then, combining antibody pairs as probes and HB-LMs as based signal tag, a DC-LFIA was constructed, by which the visual limit of detection is 25 pg/mL, 100 pg/mL for IAV NP and RSV NP, respectively, 10-fold more sensitive than gold nanoparticles based LFIA. The calculated limit of detection (S/N=3) of IAV NP and RSV NP was improved 22.8- and19.5-fold, respectively, in comparison with gold nanoparticles based LFIA. Additionally, the developed sensor shows excellent specificity and reproducibility. Furthermore, the as-proposed method was validated through the analysis of clinical samples, in good agreement with commercial colloidal gold kits. Thus, the developed DC-LFIA has great potential for clinical application in the multiplex detection of respiratory viral antigens.

Investigation on the plugging mechanism of nanocomposite polyacrylate copolymers in water-based drilling fluids: Experiments and applications

The plugging of nanopores and cracks in shale formation has become the critical technology that promotes the development of shale gas. Herein, nanocomposite polyacrylate (Poly-TALC) copolymers were successfully prepared by emulsion polymerization using butyl acrylate and triallyl isocyanurate as the raw material. Poly-TALC was characterized by fourier transform infrared spectroscopy (FTIR), laser light scattering particle size analysis, scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The rheological properties and plugging performance of Poly-TALC were evaluated by a six-speed rotational viscometer, filter cake permeability test, core permeability test and pressure transfer experiment. Results revealed that Poly-TALC exhibited a particle size distribution ranging from 75.27 to 95.29 nm, while maintaining notable stability at 327.75 °C. Upon the addition of Poly-TALC to the drilling fluid, both the apparent viscosity and plastic viscosity insignificantly changes. At a Poly-TALC dosage of 1.0%, the filter cake's permeability was 1.2 × 10−5 μm2 with a plugging rate of 56.9%, while the permeability of the core was 1.2 × 10−6 μm2 with a plugging rate of 84.0%. The decrease in permeability was not significant beyond a Poly-TALC dosage of 1.0 wt%. Pressure transfer experiments demonstrate that Poly-TALC is able to form a multi-stage dense seal within the rock core, which can effectively prevent formation water from immersing into shale formation and improve shale wellbore stability.

Improving Shale Stability through the Utilization of Graphene Nanopowder and Modified Polymer-Based Silica Nanocomposite in Water-Based Drilling Fluids

Shale formations present significant challenges to traditional drilling fluids due to fluid infiltration, cuttings dispersion, and shale swelling, which can destabilize the wellbore. While oil-based drilling fluids (OBM) effectively address these concerns about their environmental impact, their cost limits their widespread use. Recently, nanomaterials (NPs) have emerged as a promising approach in drilling fluid technology, offering an innovative solution to improve the efficiency of water-based drilling fluids (WBDFs) in shale operations. This study evaluates the potential of utilizing modified silica nanocomposite and graphene nanopowder to formulate a nanoparticle-enhanced water-based drilling fluid (NP-WBDF). The main objective is to investigate the impact of these nanoparticle additives on the flow characteristics, filtration efficiency, and inhibition properties of the NP-WBDF. In this research, a silica nanocomposite was successfully synthesized using emulsion polymerization and analyzed using FTIR, PSD, and TEM techniques. Results showed that the silica nanocomposite exhibited a unimodal particle size distribution ranging from 38 nm to 164 nm, with an average particle size of approximately 72 nm. Shale samples before and after interaction with the graphene nanopowder WBDF and the silica nanocomposite WBDF were analyzed using scanning electron microscopy (SEM). The NP-WBM underwent evaluation through API filtration tests (LTLP), high-temperature/high-pressure (HTHP) filtration tests, and rheological measurements conducted with a conventional viscometer. Experimental results showed that the silica nanocomposite and the graphene nanopowder effectively bridged and sealed shale pore throats, demonstrating superior inhibition performance compared to conventional WBDF. Post adsorption, the shale surface exhibited increased hydrophobicity, contributing to enhanced stability. Overall, the silica nanocomposite and the graphene nanopowder positively impacted rheological performance and provided favorable filtration control in water-based drilling fluids.

A novel thermosensitive porous imprinted polymer for selectively separating ReO4− based on Pickering‐like emulsion polymerization

AbstractIn this study, we combined the imprinting technique, temperature‐sensitive polymer, and Pickering emulsion polymerization to prepare a temperature‐sensitive porous imprinted polymer. First, the temperature‐sensitive block polymer PDEA‐b‐P (DEA‐co‐AM) was prepared by reversible‐addition fragmentation chain transfer polymerization, and then a temperature‐sensitive porous ReO4− imprinted polymer (ReO4−‐TPIP) was prepared using the Pickering‐like polymerization technique, which was introduced to the preparation of the imprinted polymer. The structure and morphology of the polymer were characterized by FTIR, SEM‐EDS, and BET. The adsorption experiments showed that the maximum adsorption (Q), separation (R), and desorption (D) of ReO4−‐TPIP were 0.1568 mmol/g, 3.41, and 85.22%, respectively, and the adsorption equilibrium could be reached after 120 min, which decreased to 0.1212 mmol/g, 1.23, and 70.01% after repeated use for 11 times. These results indicate that ReO4−‐TPIP has good adsorption and reusability properties. The adsorption studies showed that ReO4−‐TPIP conformed to the zero‐level kinetic model in the pre‐adsorption stage, the quasi‐one‐level kinetic model in the late stage, and the isothermal adsorption process conformed more to the Langmuir model. In addition, in the secondary leach solution of high‐temperature alloys, the purity of rhenium in the solution increased from 35.4119% to 53.4812% after one adsorption/desorption cycle. The prepared ReO4−‐TPIP provides a new material and strategy for the selective separation and purification of rhenium in complex rhenium‐containing solutions for the industry.

Recent Update on Applications of Nanostructured Lipid and Solid Lipid Nanocarriers Carriers in Drug Delivery Systems: a Narrative Review

Objective: The review article highlights the development of nano-formulations like solid lipid nanocarriers and nanostructured lipid carriers and their applicability in different drug delivery systems. Significance: In order to get around some of the drawbacks of traditional formulations, lipid base delivery save received increased interest in recent years. These lipidic carriers are created to get around the drawbacks of other colloidal carriers, including polymeric nanoparticles, emulsions, and liposomes, which have the advantages of great physical stability, a favorable release profile, and tailored drug delivery. Conclusion: Nanostructured lipid carriers are an up-and-coming type of nano-carrier that can be used to develop highly effective and customized treatments for cancer chemotherapy. Changing their surface can help target specific areas and make them work better while lowering the side effects of high doses, which is essential for dealing with drug resistance in cancer chemotherapy.

Biocide-encapsulated core–shell polymer microspheres: A novel approach for preparing long-lasting antimicrobial coatings

Antimicrobial coatings play a crucial role in combating pathogenic microorganisms. However, developing long-lasting antimicrobial coatings presents substantial challenges. In this study, we developed a robust method for fabricating durable antimicrobial coatings using crosslinked, biocide-encapsulated core–shell polymer microspheres. These microspheres were prepared by emulsion polymerization, facilitating simultaneous synthesis and biocide loading. Designed with a hydrophilic shell and a hydrophobic core, the microspheres predominantly stored the hydrophobic biocides within the core, thus reducing the biocide concentration at the shell. This design, which is governed by Fickian diffusion, substantially slowed the rate of biocide migration from the shell to the external environment, thereby enhancing the coating's antimicrobial longevity. The synthetic process for these biocide-encapsulated microspheres was optimized to encapsulate biocides with a Log P range of 1–3, achieving an encapsulation efficiency exceeding 85 % for all tested biocides. Specifically, microspheres containing N-butyl-1,2-benzisothiazolin-3-one (BBIT) were used to develop an antimicrobial coating. The coating can be applied to various substrates, including glass, metal, wood, ceramics, and plastics. It exhibits excellent hardness, adhesion, mechanical strength, and solvent resistance on these surfaces. Antimicrobial tests and release analyses demonstrated that the coating maintains high biological activity for at least 10 months, effectively inhibiting bacterial and fungal growth. The release behavior of the coating adhered to the Peppas–Sahlin model, with diffusion as the predominant mechanism. The model predicted an antimicrobial retention rate of over 66 % after 1 year, confirming its sustained antimicrobial effectiveness.

Synthesis and characterization of natural rosin-modified silica nanocomposite and its green multifunctional applications for drilling fluid

The increasing energy demand and environmental pressure require the utilization of high-performance and eco-friendly drilling fluid materials for oil/gas exploration. Herein, a green nanocomposite involving the core structure of silica (SiO2), the resin shell structure of rosin dehydroabietic acid (DHAA) derivative [poly(DHAA-co-styrene) (PDS)], and the crown structure of hydrophilic layer [crosslinked poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-N, N-dimethylacrylamide) (CAD)] was prepared through semi-continuous emulsion polymerization and utilized as a high-performance and multifunctional additive for drilling fluid. The optimal composition of core, shell and crown was determined to be 0.3: 10: 2 in mass, and the DHAA component accounted for 50 wt% in the shell structure and the molar ratio of 2-acrylamido-2-methyl-1-propanesulfonic acid and N, N-dimethylacrylamide in the crown was 3:7. The core-shell-crown nanocomposite (SiO2-PDS-CAD) exhibited a well-organized multi-layered nanostructure with an effective encapsulation of PDS on nano-SiO2 and CAD on PDS, facilitating a uniform nano-dispersion of SiO2-PDS-CAD. The bulky copolymerized rosin-based segments coupled with nano-SiO2 resulted in high thermal stability of SiO2-PDS-CAD and broadened the softening point of raw rosin from 87°C to 141°C. Meanwhile, the environmental assessments of acute toxicity and biodegradability showed that SiO2-PDS-CAD was nontoxic and readily biodegradable, and the higher incorporation of rosin components enabled SiO2-PDS-CAD more biodegradable in contrast to the non-biodegradability of the analog without rosin. Moreover, SiO2-PDS-CAD showed versatile functions in bentonite-based drilling fluid by maintaining high yield points, lowering fluid loss and enhancing nano-porous plugging capacity (100–400 nm), especially at elevated temperatures (140–180°C). A maximum increment of 1200 % on yield point occurred after aging 170°C, and the highest improvement of approximately 72 %-75 % on fluid loss occurred at 150–180°C. It also could effectively inhibit clay swelling and decrease the lubrication coefficient. The enhancement mechanism was revealed to be the core-shell-crown synergistic effects, in which the hydrophilic crown contributed to the dispersion stability of SiO2-PDS-CAD and affinity with bentonite clay, and the rigid bridging of core and flexible deformation of rosin shell strengthened the interparticle interactions. The study highlighted a novel strategy for preparing high-value-added rosin-based biomass material for green multifunctional applications in water-based drilling fluids.

A piece-wise reconstruction of some mechanistic steps in Pickering emulsion polymerization: a semicontinuous styrene montmorillonite-supported process as a case example

AbstractBuilding on traditional emulsion polymerization research, which continues to yield results up to the present day, techniques have emerged to produce hybrid materials. One such technique is Pickering emulsion polymerization, with numerous industrial applications. Despite a growing interest in Pickering emulsion polymerization, the intrinsic mechanisms involved have been based mainly on the findings of classical emulsion polymerization. In this work, by relying on a minimum of assumptions and using a simple model and experimental data on conversion and particle size, we obtain information about the prevailing mechanisms. More specifically, we present four main findings based on data reported previously in the literature. First, in contrast to the three rate-of-reaction intervals reported in classical emulsion polymerization, the integro-differential method yielded only two rate-of-reaction intervals against conversion. Second, a master curve is constructed by plotting the reaction rate against overall conversion, showing a maximum of approximately 55% conversion. Third, despite having a semicontinuous process, monomer concentration inside the particles is not constant. Finally, particle density is a strong function of the Pickering agent concentration, where two fitting parameters (nucleation and coagulation) allowed an accurate description for the particle number time evolution. Both parameters showed a power-law dependence with clay concentration.

On the Mechanism of Nucleation and Monomer Transport in Inverse Emulsion Polymerization

On the Mechanism of Nucleation and Monomer Transport in Inverse Emulsion Polymerization

Fast Determination of Eleven Food Additives in River Water Using C18 Functionalized Magnetic Organic Polymer Nanocomposite Followed by High-Performance Liquid Chromatography.

A novel magnetic nanomaterial with Fe3O4 as the core, PS-DVB as the shell layer, and the surface modified with C18 (C18-PS-DVB-Fe3O4) had been synthesized by seeded emulsion polymerization. C18-PS-DVB-Fe3O4 retains the advantages of the chemical stability, large porosity, and uniform morphology of organic polymers and has the magnetic properties of Fe3O4. A simple, flexible, and efficient magnetic dispersive solid phase extraction (Mag-dSPE) method for the extraction of preservatives, sweeteners, and colorants in river water was established. C18-PS-DVB-Fe3O4 was used as an adsorbent for Mag-dSPE and was coupled with high-performance liquid chromatography (HPLC) to detect 11 food additives: acesulfame, amaranth, benzoic acid, tartrazine, saccharin sodium, sorbic acid, dehydroacetic acid, sunset yellow, allura red, brilliant blue, and erythrosine. Under the optimum extraction conditions, combined with ChromCoreTMAQC18 (5 μm, 4.6 × 250 mm), 20 mmol/L ammonium acetate aqueous solution and methanol were used as mobile phases, and the detection wavelengths were 240 nm and 410 nm. The limits of detection (LODs) of 11 food additives were 0.6-3.1 μg/L with satisfactory recoveries ranging from 86.53% to 106.32%. And the material could be reused for five cycles without much sacrifice of extraction efficiency. The proposed method has been used to determine food additives in river water samples, and results demonstrate the applicability of the proposed C18-PS-DVB-Fe3O4 Mag-dSPE coupled with the HPLC method to environment monitoring analysis.

Encapsulated inorganic pigments in epoxy composite microspheres using emulsion synthesis

Inorganic pigments are a commonly used colorant with various applications and promising prospects. However, the implement of organic pigments is hindered by poor dispersion stability in coatings due to non-uniform morphology and size. Herein, encapsulated pigments of Cobalt Chrome Green CoCr2O4 (PG 26), Cobalt Blue CoAl2O4 (PB 28), Titanium Chrome Yellow TiCrSbO6 (PB 24) in epoxy microspheres are obtained via an oil-in-water emulsion polymerization. The morphology, particle size, thermal properties, glass transition temperature (Tg) and color performance of the composite microspheres were characterized by different analytical techniques. The average particle size varied with pigments types and loadings. When the content of CoCr2O4 and CoAl2O4 is in the range of 15 wt%-30 wt%, and TiCrSbO6 content is between 15 wt%-25 wt%, the composite microspheres exhibit a narrow particle size distribution, regular morphology, and smooth surface. The size followed the rule of CoAl2O4/epoxy (20–26 μm) > CoCr2O4/epoxy (14-16μm) > TiCrSbO6/epoxy (6–9 μm). Besides, according to the aggregation-induced emission (AIE) principle, the relationship between fluorescence intensity and reaction time was investigated, thus deducing the curing process of the epoxy groups with m-xylenol dimethylamine (MXDA). The kinds of three inorganic fillers exhibit varying effects on the diffusion process of MXDA. TiCrSbO6 promotes the progress of the epoxy-amine curing reaction. Notably, CoCr2O4 microspheres exhibited stable green value (a*) and color saturation (C*), TiCrSbO6 microspheres showed increased yellow value (b*) and saturation (C*), and CoAl2O4 microspheres enhanced blue value (b*) with minimal change in lightness (L*). Overall, this study provides a comprehensive understanding of the properties of inorganic pigment/epoxy composite microspheres and highlights their potential for improved dispersion stability in coating applications.

Overcoming Challenges of Incorporation of Biobased Dibutyl Itaconate in (Meth)acrylic Waterborne Polymers.

Polymeric derivatives of itaconic acid are gaining interest as biobased alternatives to petroleum-based monomers due to their versatility, renewable nature, commercial availability, and cost-effectiveness. Itaconate ester monomer's challenges incorporating in (meth)acrylic waterborne polymers are the low propagation rate, unfavorable reactivity ratios, and the depropagation process. To overcome these challenges, the seeded semibatch emulsion polymerization of 100% biobased dibutyl itaconate, methyl methacrylate, and butyl acrylate was investigated at different temperatures. Consequently, 30 wt % DBI was successfully incorporated within waterborne (meth)acrylates in short reaction times (4 h), obtaining high DBI incorporation (>90%). The results demonstrate that DBI incorporation influences the instantaneous monomer conversion, polymer's microstructure, and mechanical properties. By incorporating a biobased itaconate cross-linker, kinetics and mechanical characteristics of the polymers were improved. This combined approach can be implemented without altering industrial processes, resolving the commercialization dilemma for itaconate monomers to synthesize high-performance biobased polymers for adhesive and coating industries.

Aqueous RAFT Dispersion Polymerization Mediated by an ω,ω-Macromolecular Chain Transfer Monomer: An Efficient Approach for Amphiphilic Branched Block Copolymers and the Assemblies.

Herein, an ω,ω-macromolecular chain transfer monomer (macro-CTM) containing a RAFT (reversible addition-fragmentation chain transfer) group and a methacryloyl group was synthesized and used to mediate photoinitiated RAFT dispersion polymerization of hydroxypropyl methacrylate (HPMA) in water. The macro-CTM undergoes a self-condensing vinyl polymerization (SCVP) mechanism under RAFT dispersion polymerization conditions, leading to the formation of amphiphilic branched block copolymers and the assemblies. Compared with RAFT solution polymerization, it was found that the SCVP process was promoted under RAFT dispersion polymerization conditions. Morphologies of branched block copolymer assemblies could be controlled by varying the monomer concentration and the [HPMA]/[macro-CTM] ratio. The branched block copolymer vesicles could be used as seeds for seeded RAFT emulsion polymerization, and framboidal vesicles were successfully obtained. Finally, degrees of branching of branched block copolymers could be further controlled by using a binary mixture of the macro-CTM and a linear macro-RAFT agent or a small molecule CTM. We believe that this study not only provides a versatile strategy for the preparation of branched block copolymer assemblies but also offers important insights into polymer synthesis via heterogeneous RAFT polymerization.

Flame retardant and smoke suppression properties of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide derivative/zinc molybdate sepiolite modified acrylate emulsion

AbstractAcrylate emulsion is widely used in various industrial fields and is an important polymer emulsion. However, the high flammability limits its application. Besides, acrylate emulsion generally releases a large amount of smoke during combustion. To improve the fire resistance and smoke suppression properties of acrylate emulsions, methyl methacrylate‐butyl acrylate copolymer P(MMA‐BA)/DOPO‐based polymerizable monomer (HEPO)/zinc molybdate sepiolite (Mo‐Sep) composite emulsion was prepared by emulsion polymerization, and the effect of Mo‐Sep content on the flame‐retardant performance, thermal stability, and smoke suppression performance of the composite emulsion was studied. Through microcalorimeter and smoke density meter tests, it was found that the heat release rate (HRR) of the composite emulsion, added with 30% HEPO/3% Mo‐Sep, was reduced by 63.3%, and the peak heat release rate (PHRR) was reduced by 72.1%. The total heat release (THR) is reduced by 49.0%, while the peak‐specific optical density is reduced by 48.0%. It shows that the composite emulsion has excellent flame‐retardant and smoke suppression properties compared to pure MAA‐BA emulsion. In addition, scanning electron microscope (SEM) images show that the addition of Mo‐Sep increases the density of carbon residue. This composite emulsion may have potential application scenarios in the field of flame‐retardant coatings.

Janus particles toward hierarchical functional coating and beyond

Janus particles (JPs) with two physically or chemically distinctive compartments can be employed as building blocks to achieve hierarchical functional coatings. For their amphiphilic property, JPs orientate at different interfaces of the as-formed coatings to enhance the interfaces and functionalize their surfaces. In this paper, we briefly review recent advances in JPs toward hierarchical functional coating and beyond. Since the requirements of economy and large-scale production, emulsion polymerization is an ideal method for the synthesis of JPs applied in coating industry. Ultrathin coating with single-layer particles can be directly fabricated with JPs self-orientating on the substrate. Furtherly, they are added into other latex coatings as an additive to adjust the microstructure, mechanical properties and functions of hierarchical coatings. In these methods, various functions are achieved such as superhydrophobicity, anti-corrosion, lubricity and so on.

Emulsion-Templated Gelatin/Amino Acids/Chitosan Macroporous Hydrogels with Adjustable Internal Dimensions for Three-Dimensional Stem Cell Culture.

The demand for macroporous hydrogel scaffolds with interconnected porous and open-pore structures is crucial for advancing research and development in cell culture and tissue regeneration. Existing techniques for creating 3D porous materials and controlling their porosity are currently constrained. This study introduces a novel approach for producing highly interconnected aspartic acid-gelatin macroporous hydrogels (MHs) with precisely defined open pore structures using a one-step emulsification polymerization method with surface-modified silica nanoparticles as Pickering stabilizers. Macroporous hydrogels offer adjustable pore size and pore throat size within the ranges of 50 to 130 μm and 15 to 27 μm, respectively, achieved through variations in oil-in-water ratio and solid content. The pore wall thickness of the macroporous hydrogel can be as thin as 3.37 μm and as thick as 6.7 μm. In addition, the storage modulus of the macroporous hydrogels can be as high as 7250 Pa, and it maintains an intact rate of more than 92% after being soaked in PBS for 60 days, which is also good performance for use as a biomedical scaffold material. These hydrogels supported the proliferation of human dental pulp stem cells (hDPSCs) over a 30 day incubation period, stretching the cell morphology and demonstrating excellent biocompatibility and cell adhesion. The combination of these desirable attributes makes them highly promising for applications in stem cell culture and tissue regeneration, underscoring their potential significance in advancing these fields.