Seeded Emulsion Polymerization Research Articles

CaCO3-TiO2 IMPREGNATED AlOE VERA-ALLYL METHACRYLATE ANTIMICROBIAL NANOEMULSION FOR COATING

The present work aims to utilize AMA/MMA/BA/Aloe Vera (AMBA) nanoemulsion for the preparation of sustainable antimicrobial coating materials. The AMBA was synthesized using a semi-continuous seeded emulsion polymerization methodology. The developed coating material has been synthesized by SEM, DSC, TGA/DTA, XRD, and FT-IR spectroscopy. Some properties such as viscosity, hot box stability gloss retention, solid content, freezethaw stability, scrub resistance, electrolytic stability, weather resistance, solvent resistance, and opacity of the coating material were also investigated. It has been found that the coating developed with a 70:30 monomer ratio shows the best results the with highest antimicrobial activity.

Revealing the Formation Dynamics of Janus Polymer Particles: Insights from Experiments and Molecular Dynamics.

Seeded emulsion polymerization is one of the best-known methods for preparing polymer particles with a controlled size, composition, and shape. It first requires the preparation of seed particles, which are then swollen with additional monomer (the same as the one used for the seed or a different one), to either increase the seed's size or change its morphology. The use of surfactants plays a central role in guaranteeing the required colloidal stability and contributing to the final shape and structure of the particles by lowering the interfacial energy between the polymer of the seed and the added monomer. We here study the polymerization of methyl methacrylate in the presence of polystyrene seed particles at various surfactant concentrations in the presence and absence of a surfactant (sodium dodecyl sulfate). We first show experimentally that the morphology of the colloidal particles can be tuned from Janus to core-shell, depending on the presence or absence of surfactant on the seeds particles' surface. Furthermore, using classical molecular dynamics simulations, we investigate the mechanism and behavior of the surfactants during the first stages of the polymerization process. We use a newly developed approach based on contact statistical analysis to confirm the critical role played by the organization of surfactant molecules on the surface of the seed particles in dictating the final particle morphology.

Thermomechanical study on toughened PVC with an impact modifier based on the acrylonitrile-styrene-acrylate core-shell particles

Development of impact modifiers with the core-shell structure for enhancing toughness of rigid polymers have attracted a great deal of interest. In this study, poly (butyl acrylate) (PBA) as the core was prepared via emulsion polymerization and subsequently grafted with styrene and acrylonitrile (SAN) to construct the shell layer through seeded emulsion polymerization and to produce ASA particles. Then, ASA particles containing 40, 50, and 60 wt% of PBA core and those with non-crosslinked shell were compounded with PVC through melt-blending technique in different compositions. DLS, SEM and TEM analyses revealed uniform spherical core-shell morphologies with average particle size of 170–190 nm. Cross-sectional SEM images exhibited a well-distribution and dispersion of ASA particles in PVC matrix relative to the non-crosslinked one. This can be attributed to the formation and grafting of the rigid thermoplastic SAN layer on the PBA core. Impact results of the prepared compounds showed an increasing trend with the increase in core content and also amount of ASA. The highest impact strength (135 kJ/m2) was found for the compound containing 15 wt% of ASA (with 60 wt% of PBA core) particles, which was 26 times higher than the neat PVC (5 kJ/m2). A comparative study between PVC compounds demonstrated higher heat deformation temperature, elastic modulus, and impact strength for those containing ASA with the crosslinked shell. Remarkable compatibility with PVC matrix and enhancement in thermomechanical properties for the prepared core-shell ASA particles revealed their promising potential for toughening of PVC.

Surface Nucleation-Induced Raspberry-like PVDF@P(St-co-MPS-co-AA) Core–Shell Latex Particles via Seeded Emulsion Polymerization and Their High Efficiency for Confined Crystallization of PVDF in Nanospheres

Surface Nucleation-Induced Raspberry-like PVDF@P(St-<i>co</i>-MPS-<i>co</i>-AA) Core–Shell Latex Particles via Seeded Emulsion Polymerization and Their High Efficiency for Confined Crystallization of PVDF in Nanospheres

Durability improvement mechanism of polymer cement protective coating based on functionalized MXene nanosheets modified polyacrylate emulsion

Polymer cement coatings (PCCs) have a wide range of applications in the field of concrete protection. Excellent durability of the PCCs is extremely essential for protecting the concrete in long-time service life. However, one of the most popular polymer emulsion, polyacrylate based cement coatings show insufficient durability and restrict their wide application in complicated and harsh environment. In this study, the novel two-dimensional nanomaterial MXene was incorporated to PCCs for improving the durability of the PCCs, the MXene was functinalized by vinyl triethylsilane (VTEO) (V-MXene) followed by in-situ seed emulsion polymerization method to synthesize the V-MXene modified polyacrylate emulsion. The effects of V-MXene incorporation on the rheological property, mechanical properties, bonding strength, UV aging resistance, saltwater immersion resistance, thermal aging resistance of PCCs were systematically investigated and the durability improvement mechanism was revealed. When the V-MXene dosage is 0.15 wt%, the tensile strength and bonding strength of the PCCs increased by 28.76 % and 30.84 % as compared with the blank samples, respectively. The introduction of V-MXene to PCCs can remarkably improve the UV aging resistance, saltwater immersion resistance, heat resistance. The V-MXene can decrease the UV radiation energy absorbed into the PCCs, and can create a “labyrinth effect”, prolonging the penetration path of water and corrosion ions. The V-MXene can also enhance the cross-linking density of the polymer phase combined with organic and inorganic interpenetrating networks, thereby enhancing the thermal stability of PCCs. This research provides a feasible strategy for the fabrication of high performance PCCs with excellent durability.

Mechanical Properties and Non-Isothermal Crystallization Kinetics of Polylactic Acid Modified by Polyacrylic Elastomers and Cellulose Nanocrystals.

In this paper, a polyacrylic elastomer latex with butyl acrylate (BA) as the core and methyl methacrylate (MMA) copolymerized with glycidyl methacrylate (GMA) as the shell, named poly(BA-MMA-GMA) (PBMG), was synthesized by seeded emulsion polymerization. Cellulose nanocrystal (CNC) was dispersed in the polyacrylic latex to prepare PBMG/CNC dispersions with different CNC contents. The dried product was mixed with polylactic acid (PLA) to fabricate PLA/PBMG/CNC blends. The addition of PBMG and PBMG/CNC improved the mechanical properties of the PLA matrix. Differential scanning calorimetry (DSC) was used to investigate the non-isothermal crystallization kinetics. The Avrami equation modified by the Jeziorny, Ozawa and Mo equations was used to analyze the non-isothermal crystallization kinetics of PLA and its blends. Analysis of the crystallization halftime of non-isothermal conditions indicated that the overall rate of crystallization increased significantly at 1 wt% content of CNC. This seemed to result from the increase of nucleation density and the acceleration of segment movement in the presence of the CNC component. This phenomenon was verified by polarizing microscope observation.

Fabrication of Novel Crosslinking Carboxylic Styrene-Acrylate Latices as Binders for Exterior Flexible Facing Tiles.

To overcome the shortcomings of the temperature sensitivity of exterior flexible facing tiles (EFFIs), a series of crosslinking carboxylic styrene-acrylate (SA) latices were prepared via the semicontinuous seed emulsion polymerization of glycidyl methacrylate (GMA), methacrylic acid (MAA), acrylic acid (AA), butyl acrylate (BA), and styrene (St), and were applied as binders to fabricate EFFTs with mineral powder. The obtained latices exhibited Bragg diffraction because of the narrow particle size distribution. Owing to the low dosage of emulsifiers and the crosslinking reaction between the epoxy group and the carboxyl group, the latex films displayed excellent water resistance, with water adsorption as low as 7.1%. The tensile test, differential scanning calorimeter (DSC) test, and dynamic mechanical analysis (DMA) indicated that at a GMA dosage of 4-6% the latex films had high mechanical strengths, which remained relatively stable in the temperature range of 10 to 40 °C. The optimal AA dosage was found in the range of 2 to 3%, at which the wet mixture exhibited good processability, conducive to forming an EFFT with a compact microstructure. Using the optimal SA latex, the obtained EFFT displayed a series of improved performances, including low water absorption, high mechanical strength, and stable self-supporting ability over a wide temperature range, exhibiting the application potential in the decoration and construction industries.

Preparation and Characterization of Self-crosslinked Acrylate Emulsified with Environmentally Friendly Surfactants

The self-crosslinking polyacrylate latex was prepared via the semi-continuous seed emulsion polymerization technology that methyl methacrylate(MMA) and butyl acrylate (BA)were used as the main monomers and hexafluorobutyl methacrylate (HFMA) and monobutylitaconate (MBI) were used as the modified monomers and glycidyl methacrylate (GMA) was used as the crosslinked monomer which were emulsified with the environmentally friendly mixed surfactant of the isomeric triethylene (9) ether (E-1309) and the lauryl polyoxyethylene ether sulfosuccinate disodium salt (MES-30). The resultant latex and its film is characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), laser particle sizer, contact angle determinator. The comparison of thermal stability between the resultant latex and conventional latex is carried out via the thermogravimetric analyzer (TGA). Factors, which have an influence on the properties of the resultant latex and the emulsion polymerization, are studied in detail. Results indicate that the thermal decomposition temperature of the latex film was increased from 336.9 °C to 370.1 °C The contact angle of the latex film is 82.9 ° owing to the introduction of GMA and MBI.

Engineering the surface patchiness and topography of polystyrene colloids: From spheres to ellipsoids

HypothesisColloidal surface morphology determines suspension properties and applications. While existing methods are effective at generating specific features on spherical particles, an approach extending this to non-spherical particles is currently missing. Synthesizing un-crosslinked polymer microspheres with controlled chemical patchiness would allow subsequent thermomechanical stretching to translate surface topographical features to ellipsoidal particles. ExperimentsA systematic study using seeded emulsion polymerization to create polystyrene (PS) microspheres with controlled surface patches of poly(tert-butyl acrylate) (PtBA) was performed with different polymerization parameters such as concentration of tBA monomer, co-swelling agent, and initiator. Thermomechanical stretching converted seed spheres to microellipsoids. Acid catalyzed hydrolysis (ACH) was performed to remove the patch domains. Roughness was characterized before and after ACH using atomic force microscopy. FindingsPS spheres with controlled chemical patchiness were synthesized. A balance between two factors, domain coalescence from reduced viscosity and domain growth via monomer absorption, dictates the final PtBA) patch features. ACH mediated removal of patch domains produced either golf ball-like porous particles or multicavity particles, depending on the size of the precursor patches. Patchy microspheres were successfully stretched into microellipsoids while retaining their surface characteristics. Particle roughness is governed by the patch geometry and increases after ACH. Overall, this study provides a facile yet controllable platform for creating colloids with highly adjustable surface patterns.

Synthesis of Composite Polymer Particles by Seeded Emulsion Polymerization and Formation of Photonic Crystals Based on Them

Synthesis of Composite Polymer Particles by Seeded Emulsion Polymerization and Formation of Photonic Crystals Based on Them

Synthesis of Composite Polymer Particles by Seeded Emulsion Polymerization and Formation of Photonic Crystals Based on Them

Submicron composite particles with the core/shell structure are synthesized by the seeded emulsion polymerization of a mixture of various acrylates in the presence of a redox initiation system. The diameter, morphology, and surface structure of particles as well as their ability to self-assemble into 3D ordered thin-film structures are studied by scanning electron microscopy, FTIR spectroscopy, thermogravimetry, and dynamic light scattering. It is shown that under the used experimental conditions particles with a shell thickness of 10‒35 nm are synthesized. The effect of shell composition (in particular, the alkyl chain length of acrylate comonomers) on the morphology and structure of the surface layer of the obtained composite particles is traced.

Core-shell structured polystyrene microspheres for improving plugging performance of oil-based drilling fluids

To avoid damage to wellbore stability in shale formations from drilling fluid intrusion and pressure transmission, it is important to develop a plugging material that can effectively plug micropores and fractures in shale formations. In this paper, polystyrene microspheres (CPM) with core-shell structure were synthesized by seed emulsion polymerization, and characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), particle size analysis, TEM observation and contact angle test. The effects of CPM on emulsion stability and emulsion rheological performance were evaluated by electrical stability tests and rheological performance tests, respectively. The plugging performance was evaluated using filter materials with different pore sizes as filter media. The experimental results showed that CPM had good thermal stability with a thermal decomposition temperature up to 374.3 °C. CPM had a core-shell structure with a median value (D50) of 229 nm and a three-phase contact angle of 116.2°. The synergistic effect of CPM and organoclay can significantly improve the stability of emulsions and viscosity at low shear rates. For different pore sizes of filter media, CPM achieved effective plugging of micropores, reducing fluid loss volume to less than 6 mL for different pore sizes of micropore filter membranes and 29.6% for ceramic sand discs. In this paper, a preparation method of plugging material with good plugging performance was given, which provided technical support for the development of plugging agents for Oil-based drilling fluids (OBDFs).

Temperature and pH-responsive PNIPAM@PAA Nanospheres with a Core-Shell Structure for Controlled Release of Doxorubicin in Breast Cancer Treatment

Stimuli-responsive polymers have been of great interest in the fabrication of advanced drug delivery systems. In this study, a facile approach was developed to synthesize a dually temperature/pH-responsive drug delivery system with a core-shell structure to control the release of doxorubicin (DOX) at the target site. For this purpose, poly(acrylic acid) (PAA) nanospheres were first synthesized using the precipitation polymerization technique and were used as pH-responsive polymeric cores. Then, poly(N-isopropylacrylamide) (PNIPAM) with thermo-responsivity properties was coated on the outer surface of PAA cores via seed emulsion polymerization technique to render monodisperse PNIPAM-coated PAA (PNIPAM@PAA) nanospheres. The optimized PNIPAM@PAA nanospheres with an average particle size of 116.8 nm (PDI= 0.243), had a high negative surface charge (zeta potential= -47.6 mV). Then, DOX was loaded on PNIPAM@PAA nanospheres and the entrapment efficiency (EE) and drug loading (DL) capacity were measured to be 92.7% and 18.5%, respectively. The drug-loaded nanospheres exhibited a low leakage at neutral pH and physiological temperature, but drug release significantly enhanced at acidic pH (pH= 5.5), indicating the tumor-environment responsive drug release behavior of the prepared nanospheres. Also, kinetics studies showed that, the sustained release of DOX from PNIPAM@PAA nanospheres was consistent with the Fickian diffusion mechanism. Moreover, the anticancer efficacy of DOX-loaded nanospheres was evaluated in vitro against MCF-7 breast cancer cells. The obtained results revealed that, the incorporation of DOX into PNIPAM@PAA nanospheres increases its cytotoxicity against cancer cells compared to the free DOX. Our results suggest that, PNIPAM@PAA nanospheres can be considered as a promising vector to release anticancer drugs with dual-stimuli responsivity to pH and temperature.

Preparation and Characterization of Nano-Fe3O4 and Its Application for C18-Functionalized Magnetic Nanomaterials Used as Chromatographic Packing Materials.

A new type of magnetic nanomaterial with Fe3O4 as the core and organic polymer as the shell was synthesized by seed emulsion polymerization. This material not only overcomes the problem of insufficient mechanical strength of the organic polymer, it also solves the problem that Fe3O4 is prone to oxidation and agglomeration. In order to make the particle size of Fe3O4 meet the requirement of the seed, the solvothermal method was used to prepare Fe3O4. The effects of the reaction time, amount of solvent, pH value, and polyethylene glycol (PEG) on the particle size of Fe3O4 were investigated. In addition, in order to accelerate the reaction rate, the feasibility of preparing Fe3O4 by microwave was studied. The results showed that under the optimum conditions, the particle size of Fe3O4 could reach 400 nm and had good magnetic properties. After three stages of oleic acid coating, seed emulsion polymerization, and C18 modification, the obtained C18-functionalized magnetic nanomaterials were used for the preparation of the chromatographic column. Under optimal conditions, stepwise elution significantly shortened the elution time of sulfamethyldiazine, sulfamethazine, sulfamethoxypyridazine, and sulfamethoxazole while still achieving a baseline separation.

Electrochemically-Initiated RAFT Synthesis of Low Dispersity Multiblock Copolymers by Seeded Emulsion Polymerization.

We describe electrochemically initiated emulsion polymerization with reversible addition-fragmentation chain transfer (eRAFT) to form well-defined multiblock copolymers with low molar mass dispersity. We demonstrate the utility of our emulsion eRAFT process with the synthesis of low dispersity multiblock copolymers by seeded RAFT emulsion polymerization at ambient temperature (∼30 °C). Thus, a triblock, poly(butyl methacrylate)-block-polystyrene-block-poly(4-methylstyrene) [PBMA-b-PSt-b-PMS], and a tetrablock, poly(butyl methacrylate)-block-polystyrene-block-poly(styrene-stat-butyl acrylate)-block-polystyrene [PBMA-b-PSt-b-P(BA-stat-St)-b-PSt], were synthesized as free-flowing, colloidally stable latexes commencing with a surfactant-free poly(butyl methacrylate) macroRAFT agent seed latex. A straightforward sequential addition strategy with no intermediate purification steps was able to be employed due to the high monomer conversions achieved in each step. The method takes full advantage of compartmentalization phenomena and the nanoreactor concept described in previous work to achieve the predicted molar mass, low molar mass dispersity (Đ ∼ 1.1-1.2), incrementing particle size (Zav = 100-115 nm), and low particle size dispersity (PDI ∼ 0.02) for each generation of the multiblocks.

Microencapsulation of n-tetradecane with poly (methyl methacrylate-co-methacrylic acid) shell by seeded emulsion polymerisation and its thermal energy storage characteristics

This study aims to enhance the latent heat storage properties of the microcapsules by altering the amount of crosslinking agent from 3 to 20%w/w, the core-to-shell ratio from 1:1 to 2:1, and the amount of initiator from 1 to 3%. The phase change material n-tetradecane (C-14) was microencapsulated by using poly (methyl methacrylate -co- methacrylic acid) as a shell material through an oil by water-seeded emulsion polymerisation technique. The structural, morphological, and thermal properties of microcapsules were evaluated by using Fourier transform infrared spectroscopy, optical microscopy, scanning electron microscopy, differential scanning calorimetry analysis, and thermogravimetric analysis. The average particle size of the microcapsules ranges from 01 to 15 µm. The results showed that the microcapsules have a higher melting enthalpy value of 127.3 ± 0.06 J/g with a microencapsulation efficiency of 66.72% when a 20% w/w crosslinker was used. The thermal stability of the phase change material (PCM) was increased by ∼30 ± 2 °C by encapsulation.

Four Kinds of Polymer Microspheres Prepared by the Seed Swelling Method Used to Purify the Industrial Production of Phytol.

Four monodisperse porous polymer microspheres were successfully prepared by seed emulsion polymerization and used as stationary phases for HPLC and preparative high-performance liquid chromatography (Prep-HPLC). All four polymer microspheres(polystyrene-polystyrene (PS-PS), polystyrene-poly(glycidyl methylate) (PS-PGMA), polystyrene-poly(methyl methylate) and poly(glycidyl methylate)-poly(glycidyl methylate) were used for filling HPLC empty columns. According to the analysis results of the HPLC column, PS-PS and PS-PGMA microspheres were screened out as the stationary phase of Prep-HPLC. The industrial-grade phytol was successfully separated and purified, and the purity of the final phytol was as high as 99%. The two types of polymer microspheres have been applied to industrial-grade phytol purification and have been used in factories.

Morphology of polypropylene/polystyrene composite particles prepared by seeded emulsion polymerization: influence of azo initiator intrinsic charge

The morphologies of polypropylene (PP)/polystyrene (PS) composite particles obtained using different type of the initiator in the seeded emulsion polymerization of styrene with multi-hollow PP seed particles.

Preparation and Properties of Polystyrene/Polyacrylate Emulsion Based on Acetoacetate/Diamine Self-crosslinking at Ambient Temperature

In this work polystyrene/polyacrylate emulsions were obtained by a semi-continuous, seeded emulsion polymerization using methyl methacrylate (MMA), butyl acrylate (BA), butyl methacrylate (BMA), styrene (St) and 2-(methacryloyloxy)ethyl acetoacetate (AAEM) as monomers and polyether amine (D400) as crosslinker. The emulsion films were obtained by self-crosslinking of the emulsion at ambient temperature, and their mechanical and damping behaviors were investigated. Fourier transform infrared spectroscopy (FTIR) confirmed that crosslinking reactions between the acetoacetate groups of AAEM and amino groups of D400 had occurred and formed the C = C-N crosslinked structure. Moreover, tensile tests verified that the tensile strength of the film was significantly improved by the crosslinked structure, and its maximum reached 6.5 MPa, 211% higher than that of the uncrosslinked film. Besides, dynamic mechanical analysis (DMA) indicated that the crosslinking increased the glass transition temperature (Tg) and the corresponding activation energy () of the films. The results showed that the polystyrene/polyacrylate emulsion with 5 wt% AAEM and 3 wt% D400 possessed satisfying mechanical and damping properties. This work provides a reference for synthesizing self-crosslinking polystyrene/polyacrylate emulsions at ambient temperature.

Preparation and properties of quaternary phosphonium salt containing poly-acrylate emulsion

In this study, methacryloxyhexyl triphenylphosphonium bromide (Br-MHP), a quaternary phosphonium salt monomer, was synthesized and then poly-acrylate emulsion with various Br-MHP contents was prepared through seed emulsion polymerization. The chemical structure of Br-MHP and chemical composition of Br-MHP containing poly-acrylate emulsion were characterized by 1H NMR, 13C NMR, LC-MS and FT-IR, respectively. Effects of Br-MHP content on the stability of emulsion polymerization and micro-structure of the latex particles were investigated. The micro-morphology of the polymer film was observed by SEM. The film performances such as hardness, adhesive, water absorption ratio, thermal stability and antibacterial property were studied. The surface element composition of Br-MHP containing poly-acrylate film was characterized by XPS. The results show that Br-MHP monomer and poly-acrylate emulsion with various Br-MHP contents can be successfully prepared. With the increase of Br-MHP content, the emulsion polymerization stability increases while particle size of latex particles decreases. Besides, the prepared emulsions show excellent storage stability and mechanical stability. The prepared Br-MHP containing poly-acrylate films also present excellent film properties. As the content of Br-MHP increases, the water absorption ratio of the co-polymer film increases, while hardness and thermal stability decreases. Moreover, XPS result show that the quaternary phosphonium salt group is enrich on the polymer film surface, therefore, the Br-MHP containing poly-acrylate resin presents 99.99 % antibacterial efficiency against S. aureus and E. coli when Br-MHP content is only 1 wt% and 2 wt%, respectively.