Seeded Emulsion Polymerization Research Articles

Preparation of Cross-Linkable Waterborne Polyurethane-Acrylate Coating Films with Multifunctional Properties

Self-migration or unstable phase inversion occurs when the application conditions are varied, which limits the application of polyurethane-acrylate (PUA) composite films. In this paper, cross-linked polyurethane/poly(methyl methacrylate-co-borneol acrylate) shell microspheres were prepared by using the seeded emulsion polymerization method. The core-shell structure of these samples was identified by dynamic light scattering (DLS) and high-resolution transmission electron microscope (HR-TEM). Moreover, HR-TEM images indicated that the core-shell structure of the microsphere does not undergo complete phase inversion. In addition, with increasing content of borneol acrylate in the shell, the water resistance and antibacterial adhesion of films were improved. The X-ray photoelectron spectroscopy (XPS), Energy Dispersive Spectrometer (EDS), water contact angle (CA) measurements, antibacterial and anti-adhesion tests demonstrate that the C/N ratios of films from the inside to the upper surface had an obvious gradient in growth, indicating the shell component (polyborneol acrylate) was predominantly present at the surface of films after coalescence in cross-linked core-shell PUA. It was found that a suitable degree of cross-linking contributes to the segregation of the hydrophobic component (borneol groups) on the film surface. As a consequence, the excellent water resistance, cytocompatibility, and antibacterial properties endowed this series of polymer materials with promising application potential in the biomedical field.

New water-based copolymer nanoparticles and their use as eco-friendly binders for industry of flexographic ink, part I

Purpose The purpose of this paper is to prepare, characterise and evaluate nano-emulsions of copolymers of various compositions as eco-friendly binders for flexographic ink industry. Design/methodology/approach Various nano-emulsions of copolymers were prepared using styrene (St), butyl acrylate (BuAc), acrylic acid (AA) and acrylamide (AAm) monomers by means of a conventional seeded emulsion polymerisation technique, using K2S2O8 as the initiator. The characterisation of the prepared emulsions was performed using Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), gel permeation chromatography (GPC) and transmission electron microscopy (TEM). A selection of copolymers was formulated with pigments and additional ingredients, as water-based flexographic inks. The inks were characterised for their viscosity, pH, degree of dispersion, water resistance and colour density. Findings It was found that the low viscosity of the prepared copolymers may reduce the film thickness of the flexographic inks and may also increase the spreading of the ink on the surface. As a result, stable modified polyacrylate-based latex with improved physico-mechanical properties were obtained. The prepared latexes were showed improving and enhancing in water resistance; gloss values, and the print density that ranged from 2.06 to 2.51 and the maximum gloss values (39 and 48) were also obtained. Also, these binders provide excellent adhesion properties for both the pigment particles and the base paper. Practical implications This study focuses on the preparation of new water-based copolymer nanoparticles and their use as eco-friendly binders for flexographic ink industry. Social implications The ink formulations developed could find use in industrial-scale printing. Originality/value Eco-friendly environment ink formulations for printing on paper substrates are novel.

Synthesis of double-responsive magnetic latex particles via seeded emulsion polymerization using macroRAFT block copolymers as stabilizers

We report the synthesis of magnetic latex particles decorated with double-responsive PDMAEMA segments with fast magnetic response via RAFT-assisted emulsion polymerization, highlighting this strategy as a powerful tool for magnetic carriers design.

Probing the morphology evolution of chemically anisotropic colloids prepared by homopolymerization- and copolymerization-induced phase separation

Chemically anisotropic colloids prepared by polymerization-induced phase separation during seeded emulsion polymerization with non-crosslinked seeds reveals tunability in both surface and interior properties based on the morphology evolution.

Innovative Method for Laponite Encapsulation into Polymer Latex Particles by Clay Cluster-Seeded Emulsion Polymerization

We herein report an innovative pathway for the encapsulation of Laponite platelets into polymer nanoparticles via free radical polymerization in heterogeneous aqueous medium. Hydrophobization of the Laponite platelets was performed via double functionalization of the clay basal surfaces and edges by a cationic surfactant and an organosilane, respectively. The hydrophobized platelets were then dispersed in toluene and ultrasonicated with an aqueous solution of an anionic surfactant to form clay-loaded toluene droplets. The droplets were subsequently transformed into clusters by toluene evaporation and finally encapsulated into polymer latex particles using a seeded-emulsion polymerization process. Two different copolymers were synthesized: poly(styrene-co-methyl acrylate), as a model system and poly(vinylidene chloride-co-methyl acrylate), a specialty film-forming copolymer. Stable composite particles with a diameter ranging from 150 to 180 nm were obtained for both copolymers. Transmission electron microscopy analysis showed that the Laponite clay platelets were successfully encapsulated into the polymer latex particles. The films cast from the composite suspensions of poly(vinylidene chloride-co-methyl acrylate)/clay particles showed spherical inclusions of clay tactoids dispersed within the polymer matrix.

Preparation and properties of negatively charged styrene acrylic latex particles cross-linked with divinylbenzene

In this study, the synthesis of divinyl benzene (DVB) cross-linked styrene (Sty)/butyl acrylate (BA)/acrylic acid (AAc) copolymer (SAC) latex particles via the semibatch seeded emulsion polymerization of poly(Sty/BA/AAc) seeds and Sty/BA/AAc or Sty/BA/AAc/DVB monomers was investigated. The structures and morphologies of SAC latex particles were explained by means of DSC, TG/DTG, SEM, 1H-NMR, FTIR, MFFT, and DLS techniques. Optimization studies showed that while the mass ratio of BA in the latex was 68, the glass transition temperature (Tg) value became − 19.8 °C, and when the mass ratio of BA decreased to 30, the Tg value increased to 31.5 °C. The glass transition characteristics of SAC latex were affected by the addition of DVB. The Tg for 0, 0.5, 1.0, 1.5, and 2.0 wt.% DVB/SAC latex particles is 7.5, 8.1, 22.8, 23.4, and 24.5 °C, respectively. The presence of DVB moiety in the SAC latex particles caused the increased thermal stability. The degradation step of the acrylate ester became more dominant with the increasing amount of DVB in the latex. The average particle size and polydispersity index values revealed that the DVB cross-linked SAC latex particles have satisfactory stability and good dispersibility.

Preparation and properties of long chain based polyacrylate latex

The long carbon chain monomer modified polyacrylate latex was successfully prepared by semi-continuous seeded emulsion polymerization. In this work, methyl methacrylate and butyl acrylate were used as main monomers; stearyl acrylate was used as functional monomer, which were emulsified with the novel mixed surfactants of disodium laureth sulfosuccinate (AEMES) and alkylphenol ethoxylates (OP-10) and initiated with 2,2′-azobis (2-methyl propion- amidine) dihydrochloride initiator. The structure of the resultant latex was characterized by Fourier transform infrared spectroscopy. The differential scanning calorimetry, thermogravimetric analysis and contact angle were used to test the properties of the latex film. The particle size of the latex was measured by the Zetatrac dynamic light scattering detector. Factors, which have an influence on the properties of the latex and its film, have been investigated in detail. Results show that the optimal condition of synthesizing the latex is as follows: the amount of emulsifiers is 4%; the mass ratio of AEMES to OP-10 is 3:1; the amount of initiator is 0.7%; the content of SA is 6%.

Evaluation of Styrene/Butyl-Acrylate as modifier additive in (NBR) compounds Vulcanizates

Styrene/butyl acrylate (SBt) was prepared using in-situ seed emulsion polymerization and precipitated in an excess of methanol. The prepared (SBt) was utilized as modifier additive for acrylonitrile–butadiene rubber (NBR) in different dosage i.e. 5 phr, 10 phr, 15 phr and 20 phr. The rheometric and the physicomechanical characteristics of the vulcanizates include tensile strength, elongation at break, and swelling in toluene and motor oil were studied at room temperature before and after aging at 90 oC for up to 7 days. Moreover, morphology and dielectric properties of the modified (NBR) vulcanizates were investigated as well. It was discovered that 20 phr of the Styrene/butyl acrylate (SBt) that incorporated with (NBR) has the highest physicomechanical characteristics as well as dielectric parameters.

Preparation of monodisperse porous polymeric ionic liquid microspheres and their application as stationary phases for HPLC

In recent decades, ionic liquid-modified packing materials as stationary phases of high performance liquid chromatography (HPLC) have attracted widespread attention due to their comprehensive properties. In this work, monodisperse porous polymeric ionic liquid microspheres were directly prepared using a seeded emulsion polymerization method and applied as stationary phase of HPLC. The effects of porogen, monomer and crosslinker on the properties of porous P(IL-DVB) microspheres were investigated in detail. Porous P(IL-DVB) microspheres with good stability, monodispersity and relatively high specific surface area were selected as stationary phase to successfully separate benzene and its homologues, and nucleosides and alkaloids under reversed phase chromatography (RPLC) mode and hydrophilic interaction chromatography (HILIC) mode, respectively.

Polymerization Induced Phase Separation in Composite Latex Particles during Seeded Emulsion Polymerization

Multiphase structured latex particles have been studied and produced for decades; however, the mechanism governing the polymerization induced phase separation process in such particles remains incomplete. These particles are typically produced by starting with a first, single phase polymer particle dispersion, and then a second polymer, nearly always thermodynamically phase incompatible with the first, is polymerized within those seed particles. The Gibbs free energy change upon demixing is the driving force inducing polymer–polymer phase separation during polymerization (PIPS). However, the ultimate extent of phase separation is dictated by resistances to mutual polymer chain diffusion within the latex particles. Here, we have elucidated and quantified the contributions of thermodynamic driving force and kinetic diffusive limitations to polymer–polymer phase separation within composite nanoparticles. We present a means to evaluate both the influence of chemistry and process conditions on a master plot pr...

Synthesis and characterization of size-tunable core-shell structural polyacrylate-graft-poly(acrylonitrile-ran-styrene) (ASA) by pre-emulsion semi-continuous polymerization

The core-shell polymeric polyacrylate-graft-poly(acrylonitrile-ran-styrene)(ASA) has been explored for the polymer industry due to its excellent properties. However, it has been a longstanding challenge to synthesize large size-tunable particles by the conventional batch polymerization. In this paper, an accurate method, i.e. pre-emulsion semi-continuous polymerization, is applied to prepare ASA polymeric particles, which makes a series ofdifferent particle sizes (100–450 nm) of the crosslinked poly(butyl acrylate) (PBA) inner core coated with a hard shell using the poly(acrylonitrile-ran-styrene) (AS) copolymer. Specifically, the feed modes and proportion of seedare investigated to tune the particle size.The results show that the PBA seed microsphere in pre-emulsion semi-continuous polymerization is enlarged by accurate feed rate, but not in batch polymerization. A possible mechanism for the growth of the PBA core is proposed that secondary particles from homogeneous nucleation in semi-continuous feed mode is less than that of batch mode, which attenuate the impact on the growth of core particle. The size and morphology of resulting particles are characterized using various analytical techniques including the transmission electron microscopy (TEM), the scanning electron microscopy (SEM) and the dynamic light scattering (DLS). Core-shell separates phase corresponding to different glass transition temperatures is evaluated using differential scanning calorimeter (DSC) analyses indirectly. Moreover, the mechanical properties including impacts and tensile strengths are also analyzed. This study thus highlights a detailed strategy to tune polymeric particles related to different properties and the nucleating mechanism of seed emulsion polymerization that governs structure, particle size and distribution of ASA polymer with a bespoke structure for various application.

Janus Particles with Varying Configurations for Emulsion Stabilization

Analogous to molecular surfactants, amphiphilic Janus particles can function as surface active agents to stabilize emulsions. For molecular surfactants, the shape and amphiphilicity, described by packing parameters and hydrophilic–lipophilic balance (HLB), respectively, determine the type of emulsions that are produced. However, it remains unclear which features of Janus particles determine the type of emulsion that can be stabilized by these particles. In this study, a homologous series of amphiphilic Janus particles with shifting Janus boundaries and tunable chemical properties are synthesized via seeded emulsion polymerization. We systematically study the effect of the relative size of the hydrophilic domain to the total particle (configuration) and chemical nature of Janus particles on their emulsification properties. The concept of the Janus structure parameter (JSP) is introduced to describe the configuration of Janus particles. The emulsification results show that the configuration of Janus particl...

Preparation and characterization of novel VAc/VeoVa10/DBM/VTES quadripolymer latex emulsified with green surfactants

The novel vinyl acetate (VAc)/vinyl neo-decanoate (VeoVa10)/dibutyl maleate/triethoxy vinyl silane quadripolymer latex was prepared via the semi-continuous seeded emulsion polymerization emulsified with disodium laureth sulfosuccinate (AEMES) as anionic surfactant and beta-cyclodextrin (β-CD) mixture as emulsifier and initiated with potassium persulfate (KPS), respectively. The chemical compositions of copolymer was determined by Fourier transform infrared spectromer (FTIR). The glass transition temperature ( Tg) of the copolymer was measured by differential scanning calorimetry. The water resistance of the film was assessed by the water contact angle measurement. The conditions of preparing the novel latex were optimized and obtained as follows. The amount of AEMES and β-CD mixtures were 6 wt% and the mass ratio of AEMES to β-CD were 1:1. The dosage of KPS was 0.6 wt% and the mass ratio of VAc to VeoVa10 was 3:1. The amount of dibutyl maleate and triethoxy vinyl silane was 4% and 3%, respectively. In this case, the conversion percentage of the mixed monomers was 99.0% and the polymerization stability was good.

Synthesis of poly(acrylic acid) coated magnetic nanospheres via a multiple polymerization route.

Magnetic nanospheres are versatile candidates for both fundamental and practical applications. Before they are applied in more complicated fields, their surface must be modified by several functionalities. However, the surface modification can be affected by the magnetic nanoparticles (MNP) embedded in the polymer matrix. Herein, the synthesis of poly(acrylic acid) coated magnetic nanospheres via a multiple polymerization route is described. During the synthesis process, seed emulsion polymerization was applied to redistribute the MNP in the polymer matrix, and the relationship between the structure of magnetic nanospheres and the thickness of the grafted poly(acrylic acid) layer was investigated. The development of size, morphology and magnetic properties of the nanospheres were characterized by transmission electron microscopy, dynamic light scattering, thermogravimetric analysis, X-ray diffraction and vibrating sample magnetometry. This work would pave the way to design and preparation of new structure of functional magnetic nanospheres with precise surface modification.

Water and oil repellent properties affected by the crystallinity of fluorocarbon chain in fluorine-silicon containing finishing agent

Novel soap free and core-shell typed fluorosilicon containing water and oil-repellent finishing agents were fabricated via semi-continuous seed emulsion polymerization reaction. Notably, a series of non-functional acrylate monomers with different carbon chain lengths, i.e. methyl methacrylate, ethyl methacrylate, butyl methacrylate, iso-Octyl methacrylate and lauryl methacrylate were deployed to tune the crystallinity and ordering of final polymer membranes. Experimental results reveal that the water and oil-repellent properties of treated cotton fabric were significantly affected by the crystallinity of designed products. Physical and chemical characterizations were carried out via infrared spectroscopic analysis, thermogravimetric analysis, X-ray diffraction, scanning electron microscope and transmission electron microscope techniques. The hydrostatic pressure, water contract angle, moisture resistance and oil-repellent rating of cotton fabric treated by best performed finishing agent (adopting lauryl methacrylate as non-functional monomers) were determined to be 2.87 KPa, 144.6°, 4 and 5 grade, respectively.

Recyclable, non-leaching antimicrobial magnetic nanoparticles

Pathogenic bacterial contaminations in water cause serious or even lethal threats. Strategies that effectively kill bacteria without causing environmental contamination are urgently needed in a wide range of applications. We prepared recyclable antimicrobial magnetic nanoparticles, Fe3O4@P(St-co-AcQAC), through surfactant-free seeded emulsion polymerization involving a polymerizable, hydrophobic quaternary ammonium compound (QAC). Fe3O4 particles were first synthesized by a solvothermal reaction, followed by functionalization with a methacrylic silane (MPS), and then copolymerized with a QAC-containing acrylic monomer (AcQAC), leading to Fe3O4 @P(St-co-AcQAC) nanoparticles. As confirmed by antibacterial assays, these Fe3O4@P(St-co-AcQAC) nanoparticles exhibited strong antimicrobial action against both Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli, without leaching out any bactericidal agent. An additional benefit of antimicrobial magnetic particles is that they can be easily recycled while maintaining excellent antimicrobial efficacy.

Synthesis and Characterization of Novel Poly (VAC-VeoVa-HFMA-BZMA) Latex via Semicontinuous Seeded Emulsion Polymerization

The novel poly (VAC-VeoVa-HFMA-BZMA) latex was successfully prepared via semicontinuous seeded emulsion polymerization which vinyl acetate (VAc) and vinyl ester of neodecanoic acid (VeoVa10) were main monomer, hexafluorobutyl methacrylate (HFMA) and benzyl methacrylate (BZMA) were used as functional monomer. Dodecyl benzene sulfonic acid sodium (SDBS), octylphenol polyoxyethylene ether (OP-10) and potassium persulfate (KPS) were used to be mixed emulsifier and initiator, respectively. The structure of the resultant latex is determined by Fourier transform infrared spectroscopy spectrum (FTIR). The thermal performances of latex film are studied via the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The average particle size of the latex is characterized by the dynamic light scattering(DLS).Water contact angle (WCA) is used to test the wetting property of the novel poly (VAC-VeoVa-HFMA-BZMA) latex film. The condition of synthesizing the latex was studied in detail. The optimum condition of preparing the novel latex is that the amount of emulsifier is 8.0% (wt %) and the mass ratio of SDBS to OP-10 is 2 : 1 and the mass ratio of main monomer VAc to VeoVa10 is 3 : 1. The amount of initiator is 0.8% and the amounts of HFMA and BZMA are 6.0 and 8.0% (wt %), respectively. Results indicate that the water resistance of the latex film and thermal stability are improved when the fluorine and BZMA monomers are added.

Friction and wear behavior of PTFE coatings modified with poly (methyl methacrylate)

To achieve self-lubricating coating of polymer-based composite coatings with low coefficient of friction (COF) and high wear resistance, the core-shell structure was introduced via a seeded emulsion polymerization to improve wear resistance and self-lubricating properties of the coating. The effect of polytetrafluoroethylene (PTFE) encapsulated by polymethylmethacrylate (PMMA) shell on its wear resistance and lubricating properties under reciprocating dry friction was investigated. The experimental results revealed interesting examples of: the wear rate of PTFE coating was decreased from 232 × 10−6 mm3/Nm to 1.04 × 10−6 mm3/Nm and the COF decreased from 0.081 to 0.069. During reciprocating sliding tests, the results show that a continuous, uniform and thin PTFE/PMMA composite film is transferred to the GCr15 steel ball surface. It was demonstrated that the improved lubricating performance was associated with the dispersion effect from core-shell structure, which has a characteristic size in the nanometer range, and composite thus possess a much higher uniformity and higher dispersivity of reinforcement phase than do composite obtained by the conventional filling method.

Preparation and characterisation of modified VAc-VeoVa10 latex

PurposeFluorine and silicon materials have received the keen attention of many researchers because of their water repellency and low surface free energy. The purpose this study was to prepare vinyl acetate (VAc)-vinyl ester of neodecanoic acid (VeoVa 10) copolymer latex modified with fluorine and silicone monomer, which is emulsified with the novel surfactants of disodium laureth sulfosuccinate (MES) and octylphenol polyoxyethylene ether (OP-10).Design/methodology/approachA series of modified latices containing fluorine-silicon have been prepared by semi-continuous seeded emulsion polymerisation of mixed monomers of VAc, VeoVa10, hexafluorobutylmethacrylate (HFMA) and vinyltriethoxysilane (VTES) and emulsified by novel surfactants of MES and OP-10.FindingsThe optimum conditions for preparing the modified latex is as follows: the amount of the surfactant was 4.0 Wt.% and the mass ratio of the anionic and nonionic surfactant was 3:1; the dosage of initiator was 0.4 Wt.% and the mass ratio of the main monomer was 3:1; and the amounts of VTES and HFMA were 2.0 and 6.0 Wt.%, respectively. In comparison with the conventional latex, the hydrophobicity of latex film was improved further.Originality/valueThe modified p (VAC-VeoVa) latex is prepared via semi-continuous seeded emulsion polymerisation, which is emulsified with the novel mixed surfactants of MES and OP-10. There are two main innovations. One is that the novel p (VAC-VeoVa) latex containing fluorine-silicon is prepared successfully. The other is that the emulsifier is composed of the novel mixed surfactants of MES and OP-10.

Functional Janus Particles Modified with Ionic Liquids for Dye Degradation

Snowman-like silica@PDVB/PS Janus particles were fabricated via seeded emulsion polymerization and modified with hydrophilic ionic liquid moieties. The Janus particles can readily be further modified by incorporating new functionalities through simple anion exchange. PW12O403– as a catalytically active species for dye degradation was introduced into the Janus particles, and the performance in the catalytic degradation of methyl orange was evaluated.