Emulsion Polymerization Method Research Articles

Gel Polymer Electrolyte from Ozonolysis of Poly(3-(trimethoxysilyl)Propyl Methacrylate) Graft on Natural Rubber Latex for Natural Dye Sensitized Solar Cell Application

The dye sensitized solar cell (DSSC) is devices for converting solar energy to electricity. The gel polymer electrolyte is the main component in the cell. It is used for complexation with liquid electrolyte to generate iodide ions and support the ion transportation. The gel polymer electrolyte of poly(3-(trimethoxysilyl) propyl methacrylate) (PMPS) coat on the surfaces of natural rubber (NR) particles (PMPS-g-NR) was prepared by surface grafting emulsion polymerization method using the redox couple initiator, tetraethylenepentamine (TEPA) and cumenehydroperoxide (CHP). Then, this gel was treated by ozone at different treatment time (5 min, 10 min, 20 min, 25 min, and 30 min) and voltage of ozonolysis (0.7 kV, 1.5 kV, 2.4 kV, and 3.2 kV) on PMPS-g-NR (ozonolysed PMPS-g-NR) to obtain the optimum condition for generating the active species e.g. carbonyl or aldehyde structures. The synthesized materials were characterized by the degree of swelling (%DS), ionic conductivity, and solar cell efficiency, having red cabbage as dye sensitizer. By ozonolysis on PMPS-g-NR, the treatment condition of voltage at 3.2 kV and treatment time at 30 min showed the maximum %DS of 74.2, which is higher than that of PMPS-g-NR without ozonolysis of 65.5. The maximum ion conductivity of PMPS-g-NR and ozonolysed PMPS-g-NR at 2.4 kV and 20 min were 0.240 mS/cm and 0.775 mS/cm, respectively while their maximum solar cell efficiency was 6.738 m% and 10.340 m%, respectively.

Synthesis of the Mono-Disperse Magnetic Cross-Linked Composite Micro-Spheres Containing the Functional Group

The mono-disperse magnetic cross-linked composite micro-spheres containing carboxyl groups have been prepared by an improving method of emulsion polymerization in this paper. Firstly, Fe3O4 magnetic nanoparticles were synthesized by co-precipitation, and the Fe3O4 magnetic nanoparticles were modified by oleic acid. Secondly, DVB as cross-linker, SDBS as emulsifier and AIBN as initiator, the mono-disperse magnetic cross-linked composite micro-spheres were obtained in aqueous, and consisted of the copolymer of styrene and acrylic acid as shell and the Fe3O4 magnetic nanoparticles as core. The magnetic cross-linked micro-spheres would be the rudiment of the magnetic nanonetwork, and be expected to apply a great deal of fields in the future.

Polyaniline(PANI) coated Zn2SnO4 cube as anode materials for lithium batteries

Zn2SnO4@PANI composites were synthesized via a micro emulsion polymerization method. The outer surfaces of monodispersed cubes are covered with amorphous aggregated PANI. The addition of PANI can create a buffering structure for Zn2SnO4 cubes. Compared with Zn2SnO4 cubes, Zn2SnO4@PANI composites show an improved electrochemical performance (491.0 mAh g−1 at a current density of 600 mAg−1 after 50 cycles). It is believed that PANI coating is a simple and effective way to improve the cycling performance for lithium batteries.

Sol–gel synthesis, characterization and catalytic activity of γ-alumina with bimodal mesopore distribution

In this study, boehmite sols were used for preparation of mesoporous γ-alumina with bimodal mesopore distribution. Superfine nanospheres of poly(methyl methacrylate) (PMMA) prepared by water based emulsion polymerization method were used as a template. Nitrogen sorption revealed that aluminas prepared using this approach demonstrated bimodal mesopore size distribution with maxima at 3.8 and 25.7 nm, respectively. Catalytic tests showed that bimodal mesopore distribution within γ-Al2O3 prepared with PMMA nanospheres as a template provides improved catalytic activity in the methanol dehydration reaction.

Synthesis and characteristics of poly(methacrylic acid-co -N -isopropylacrylamide) thermosensitive composite hollow latex particles and their application as drug carriers

In this work, the poly(methacrylic acid-co-N-isopropylacrylamide) thermosensitive composite hollow latex particles was synthesized by a three-step reaction. The first step was to synthesize the poly(methyl methacrylate-co-methacrylic acid) (poly(MMA-MAA)) copolymer latex particles by the method of soapless emulsion polymerization. The second step was to polymerize methacrylic acid (MAA), N-isopropylacrylamide (NIPAAm), and N,N′-methylenebisacrylamide in the presence of poly(MMA-MAA) latex particles to form the linear poly(methyl methacrylate-co-methacrylic acid)/crosslinking poly(methacrylic acid-co-N-isopropylacrylamide) (poly(MMA-MAA)/poly(MAA-NIPAAm)) core–shell latex particles. In the third step, the core–shell latex particles were heated in the presence of ammonia solution to form the crosslinking poly(MAA-NIPAAm) thermosensitive hollow latex particles. The morphologies of poly(MMA-MAA)/poly(MAA-NIPAAm) core–shell latex particles and poly(MAA-NIPAAm) hollow latex particles were observed. The influences of crosslinking agent and shell composition on the lower critical solution temperature of poly(MMA-MAA)/poly(MAA-NIPAAm) core–shell latex particles and poly(MAA-NIPAAm) hollow latex particles were, respectively, studied. Besides, the poly(MAA-NIPAAm) thermosensitive hollow latex particles were used as carriers to load with the model drug, caffeine. The effect of various variables on the amount of caffeine loading and the efficiency of caffeine release was investigated. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 5203–5214

Application of Crosslinked Ionic Poly(Vinyl Alcohol) Nanogel as Adsorbents for Water Treatment

Core-shell smart ionic nanogels based on poly(vinyl alcohol) (PVA) core and poly(N-isopropylacrylamide/acrylic acid) p(NIPAm-AAc) shell particles were successfully synthesized through a one-step surfactant-free emulsion polymerization method (SFEP). Different mole ratios of p(NIPAm-AAc) shells were synthesized. The morphologies of PVA/p(NIPAm-AAc) nanogels were investigated by transmission electron microscope (TEM). The data showed the formation of spherical nanoparticles and well-defined core-shell nanogels. PVA/p(NIPAm-AAc) core-shell nanogels were applied as a novel polymeric adsorbent to remove heavy metal pollutants from aqueous solution. Copper(II) (Cu2+) ions were selected as the target pollutant to evaluate these nanoparticles’ adsorption capability. The influence of the uptake conditions such as pH, weight ratio of nanoparticles, time, initial feed concentration, and adsorption temperature on the metal ion binding capacity of nanogels was also tested. Adsorption equilibrium data were calculated according to Langmuir and Freundlich isotherms. It was found that the sorption of Cu2+ was better suited to the Freundlich adsorption model than the Langmuir adsorption model. Also, the selectivity of the nanogels toward the different metal ions such lead (Pb2+) and cadmium (Cd2+) were tested. The maximum of Cu2+ ions adsorbed on to PVA/p(NIPAm-AAc) core-shell nanogels adsorbent was 94 mg/g obtained under simple and fast experimental conditions, indicating these nanogels can be used as effective and practical polymeric adsorbents.

Preparation of pH‐Responsive Polymer Core–Shell Nanospheres for Delivery of Hydrophobic Antineoplastic Drug Ellipticine

Antineoplastic drug ellipticine and its derivatives are used in human cancer therapy. However, their clinical applications have been limited by its great hydrophobicity and severe side effects. An efficient delivery system is therefore very desirable. In this research, an ellipticine-loaded core-shell structured nanosphere namely poly(DEAEMA)-poly(PEGMA) is designed as a drug carrier and prepared via a two-step semibatch emulsion polymerization method where DEAEMA and PEGMA represent 2-(diethylamino)ethyl methacrylate and poly(ethylene glycol) methacrylate, respectively. The in-vitro release profiles of ellipticine towards the different pH liposome vesicles are recorded as a function of time at 37 °C. It is found that release of ellipticine from the core-shell polymer matrix is a pH-responsive and controlled release process. The three pH's of 3, 4, and 5 trigger a significant ellipticine release of 88% after 98 h, 83% after 98 h, and 79% after 122 h, respectively. The release mechanism of ellipticine from the core-shell polymer matrix under acidic conditions is explored. The synthesis and encapsulation process developed herein provides a new perspective for the development of appropriate delivery systems to deliver the ellipticine and its analogues, as well as other types of hydrophobic drugs to a given target cell or tumor tissue.

Synthesis and Characterization of Magnetic Microspheres

Fe3O4 nanoparticles modified by a certain amount of oleic acid under in-situ processing were synthesized by precipitation method through dropwise adding aqueous solution of ammonia to mixed solution of Fe (II) and Fe (III) salts. Furthermore, Fe3O4/PMMA magnetic polymer microspheres were prepared by the emulsion polymerization method, which properties were characterized by the infrared spectrum, thermogravimetry analysis and scanning electron microscopy.

New bio-derived superabsorbents from nature

Superabsorbent polymers have been around for nearly half a century. Presently, petroleum-based polyacrylic acid-type polymers are used in the majority of superabsorbent applications and markets. However, the rising costs of petroleum and the lack of a sustainable supply of fossil-based chemicals is driving a need for alternative, renewable based chemicals. Herein, we report the synthesis and superabsorbent properties of novel polymers derived from nature. Free-radical, emulsion polymerization methods were used to generate cross-linked polyacrylates containing lactone functionality, which were saponified into the corresponding cross-linked ionomers in a second step. The final cross-linked products displayed >50× absorption of water per weight of polymer and absorption under load of >15× the weight of saline solution per weight of polymer. The technology also offers the opportunity to perform additional chemistry and modification to the polymer backbone in order to improve its properties.

Micron- and Nano-sized Poly(N-isopropylacrylamide-co-acrylic acid) Latex Syntheses and Their Applications for Controlled Drug Release

Thermo-sensitive poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAAm-co-AAc)) latex particles were prepared with and without sodium dodecyl sulfate (SDS) surfactant via an emulsion polymerization method. The P(NIPAAm-co-AAc) latex particle sizes were approximately 1.1 microm without SDS addition and the particle sizes were in the nanometer range (59 nm) with SDS at its critical micelle concentration (CMC) of 8 mM. We propose a scheme to demonstrate how the SDS concentration affects the synthesized latex particle size. The lower critical solution temperature (LCST) was hardly influenced by the SDS level but increased with the AAc concentration. The PNIPAAm-co-AAc latex particles were employed as thermo-sensitive drug carriers and 4-acetamidophenol was loaded to study the drug release rates from the nano-gels. The effective drug diffusion coefficients within the nano-gels varied as a function of particle size, AAc content, and temperature. The smaller or AAc-rich hydrogel particles provided sustainable drug release property and have potential use in biomedical applications.

Synthesis, Characterization and Biological Evaluation of Functionalized Polystyrene Particles

In this paper we synthesized a series of carboxylate and amino functionalized polystyrene nanoparticles with controllable size and surface properties by conventional and seed emulsion polymerization methods. They are characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). Additionally the content of carboxylate and amino groups on the surface of the particles are determined accurately by conductometric titration and fluorescamine technique respectively. Afterwards the toxicity of amino modified polystyrene particles was tested in 1321N1 astrocytoman cell line and the results showed the degree of the toxicity is proportional to the amino content of the particles, suggesting the amino group is responsible for the toxicity of the particles. Furthermore those particles were labeled by fluorescent dye and confocal fluorescent microscopy experiment showed that the particles can be well absorbed by cells.

Polybutylcyanoacrylate nanoparticles and drugs of the platinum family: last status.

Cisplatinum and carboplatinum drugs from platinum-containing family are anti-cancer drugs. Using these drugs causes side effects. Targeted and selective prescription decreases side effects of the drugs. This can be achieved using nanotechnology. In this study, cisplatinum and carboplatinum drugs were loaded on polybutylcyanoacrylate nanoparticles using emulsion polymerization method. To determine amount of loaded drug onto nanoparticle, spectrophotometry method was used. Evaluation of cytotoxicity of such nanoparticles was performed on MCF-7 cell line using MTT assay. Loading percentage of cisplatinum and carboplatinum drugs on nanoparticles were estimated 4 and 6%, respectively. Cytotoxicity survival rate for cisplatinum and nanoparticle containing cisplatinum at the lowest concentration (p<0.01) (20μM) were estimated 64±1 and 67±0.5%, respectively. These values at the highest concentration (p<0.01) (160μM) were measured 28±0.7 and 31±0.4%. Additionally for carboplatinum and nanoparticles containing carboplatinum at the concentration (p<0.01) (20μM) amounts were estimated to be 80±0.6 and 84±0.6%, while at the concentration (p<0.01) (160μM) were identified to be 44±0.5 and 51±0.2%, respectively. Probably, due to low level of loading, cytotoxicity of both drugs at nano particle status was decreased in comparison with their standard form.

PH-responsive polymer core-shell nanospheres for drug delivery

Stimuli-responsive polymer nanoparticles are playing an increasingly more important role in drug delivery applications. However, limited knowledge has been accumulated about processes which use stimuli-responsive polymer nanospheres (matrix nanoparticles whose entire mass is solid) to carry and deliver hydrophobic therapeutics in aqueous solution. In this research, pyrene was selected as a model hydrophobic drug and a pyrene-loaded core-shell structured nanosphere named poly(DEAEMA)-poly(PEGMA) was designed as a drug carrier where DEAEMA and PEGMA represent 2-(diethylamino)ethyl methacrylate and poly(ethylene glycol) methacrylate, respectively. The pyrene-loaded core-shell nanospheres were prepared via an in situ two-step semibatch emulsion polymerization method. The particle size of the core-shell nanosphere can be well controlled through adjusting the level of surfactant used in the polymerization where an average particle diameter of below 100 nm was readily achieved. The surfactant was removed via a dialysis operation after polymerization. Egg lecithin vesicles (liposome) were prepared to mimic the membrane of a cell and to receive the released pyrene from the nanosphere carriers. The in vitro release profiles of pyrene toward different pH liposome vesicles were recorded as a function of time at 37 °C. It was found that release of pyrene from the core-shell polymer matrix can be triggered by a change in the environmental pH. In particular the pyrene-loaded nanospheres are capable of responding to a narrow window of pH change from pH = 5, 6, to 7 and can achieve a significant pyrene release of above 80% within 90 h. The rate of release increased with a decrease in pH. A first-order kinetic model was proposed to describe the rate of release with respect to the concentration of pyrene in the polymer matrix. The first-order rate constant of release k was thus determined as 0.049 h−1 for pH = 5; 0.043 h−1 for pH = 6; and 0.035 h−1 for pH = 7 at 37 °C. The release of pyrene was considered to follow a diffusion-controlled mechanism. The synthesis and encapsulation process developed herein provides a new approach to prepare smart nanoparticles for efficient delivery of hydrophobic drugs. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4440–4450

Compatibility of waste rubber powder/polystyrene blends by the addition of styrene grafted styrene butadiene rubber copolymer: effect on morphology and properties

Waste rubber powder/polystyrene (WRP/PS) blends with different weight ratio were prepared with styrene grafted styrene butadiene rubber copolymer (PS-g-SBR) as a compatibilizer. The graft copolymer of PS-g-SBR was synthesized by emulsion polymerization method and confirmed through Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC). The copolymer at different weight ratio was subsequently added into the blends. The effects of weight ratio of WRP/PS and compatibilizer loading on mechanical properties were investigated. PS/WRP blends in a weight ratio of 80/20 showed higher impact strength. Moreover, the impact strength of the blend materials increased with the addition of SBR-g-PS, however, decreased at a high loading of the copolymer. The morphology and thermal properties of WRP/PS blends were examined by DSC, scanning electron microscopy (SEM), thermogravimetry (TG). DSC indicated that compared with PS/WRP blend, the glass transition temperature (Tg) of PS matrix phase in PS/WRP/SBR-g-PS blend shifted to low temperature because of the formation of chemical crosslinks or boundary layer between PS and WRP, and the Tg of WRP phase of both the PS/WRP and PS/WRP/SBR-g-PS blends did not appear. SEM results showed that interfacial adhesion in the blends with the PS-g-SBR copolymer was improved. The morphology was a typical continuous–discontinuous structure. PS and WRP presented continuous phase and discontinuous phase, respectively, indicating the moderate interface adhesion between WRP and PS matrix. TG illustrated that the onset of degradation temperature in the PS/WRP/PS-g-SBR blend decreased slightly by contrast with PS/WRP blend and the degradation of PS/WRP blends with and without SBR-g-PS was completed about at the same values.

Effect of polymerizable emulsifier and fluorine monomer on properties of self-crosslinking fluorinated polyacrylate soap-free latexes

We used a polymerizable emulsifier, ammonium allyloxtmethylate nonylphenol ethoxylates sulfate (DNS-86), to synthesize self-crosslinking fluorinated polyacrylate soap-free latices (FMBN) with a core-shell structure by a semicontinuous seeded emulsion polymerization method from dodecafluoroheptyl methacrylate (DFMA), methyl methacrylate (MMA), butyl acrylate (BA), and N-methylolacrylamide (NMA) as self-crosslinking functional monomer. Then we examined the effects of DNS-86 and DFMA on stability, average particle size and hydrophobicity of the FMBN latices or their films in detail. While dosage of the DNS-86 and the DFMA were employed as 3 wt% (on the basis of the total-monomers weight) and 8 g in our recipe, the latex and its film could be acquired with higher stability and a smaller particle size and polydispersity index, as well as favorable hydrophobicity. FTIR confirmed the structure of the FMBN. The emulsion particles’ core-shell structure was observed by transmission electron microscopy. Thermal stability of the copolymer was greatly improved with the increasing of the DFMA level. X-ray photoelectron spectroscopy analysis indicated that the fluoroalkyl groups tended to enrich at the film-air interface. Meanwhile, hydrophobicity of the self-crosslinking soap-free latex film showed some improvement compared to the general one and the non-crosslinked one.

Estrone Specific Molecularly Imprinted Polymeric Nanospheres: Synthesis, Characterization and Applications for Electrochemical Sensor Development

The aim of this study is (i) to prepare estrone-imprinted nanospheres (nano-EST-MIPs) and (ii) to integrate them into the electrochemical sensor as a recognition layer. N-methacryloyl-(l)-phenylalanine (MAPA) was chosen as the complexing monomer. Firstly, estrone (EST) was complexed with MAPA and the EST-imprinted poly(2-hyroxyethylmethacrylate-co-N-methacryloyl-(l)-phenylalanine) [EST-imprinted poly(HEMA-MAPA)] nanospheres were synthesized by surfactant- free emulsion polymerization method. The specific surface area of the EST-imprinted poly(HEMA-MAPA) nanospheres was found to be 1275 m2/g with a size of 163.2 nm in diameter. According to the elemental analysis results, the nanospheres contained 95.3 mmole MAPA/g nanosphere. The application of EST specific MIP nanospheres for the development of an electrochemical biosensor was introduced for the first time in our study by using electrochemical impedance spectroscopy (EIS) technique. This nano-MIP based sensor presented a great specificity and selectivity for EST.

Synthesis of micrometer-size poly(N-isopropylacrylamide) microgel particles with homogeneous crosslinker density and diameter control

Poly(N-isopropylacrylamide) microgel particles are synthesized using a semi-batch surfactant-free emulsion polymerization method. Particle diameter can be precisely adjusted by controlling the initial conditions, the electrolyte concentration, and the monomer feeding rate and duration. Larger particles are obtained in the presence of small amounts of co-monomer with cationic amino groups that compete against the negative charges arising from the initiator. Monodisperse particles with uniform cross-linker density, homogeneous optical properties, and pronounced thermoresponsivity are readily produced with a wide variety of diameters ranging from several hundred nanometers to a few micrometers. The charge stabilization mechanisms that control particle growth are discussed.

Surface modification of cotton fabric with dual‐responsive PNIPAAm/chitosan nano hydrogel

The present study deals with preparing stimuli‐responsive poly N‐isopropyl acryl amide/chitosan (PNCS) nano hydrogel and looks into their effects as a surface modifying system of cotton fabric. The semi‐batch surfactant‐free emulsion polymerization method was proposed to reduce the size of particle and synthesis of PNCS nano particles. Fourier transform infrared, nuclear magnetic resonance, differential scanning calorimetry, scanning electron microscopy and dynamic light scattering methods confirmed the nano size of synthesized PNCS particles and sensitivity of these nano particles to the different temperature and pH, respectively. The water retention capacity (WRC) and carboxyl content of modified cotton with PNCS nano particles were assessed through the central composite design. The bounded PNCS nano particles to the surface of cotton fabrics made them responsive to these dual stimuli. The results demonstrated the dual effect of BTCA amount on WRC. Increase of the amount of BTCA itself led to the decrease of the WRC of modified cotton, but in the presence of PNCS, WRC was significantly increased. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Synthesis of monodisperse, large scale and high solid content latexes of poly(n-butyl acrylate) by a one-step batch emulsion polymerization

Seeded emulsion polymerization and agglomerating method were well-known techniques for the production of polymeric latexes with large particle size and high solid content. Obtaining latexes with monodisperse and particle size above 300 nm scale, however, was time-consuming and difficult by means of these methods. Here, stable, monodisperse latexes with the controlled particle diameter (55–650 nm) and high solid content (60 wt%) were synthesized via one-step in batch emulsion polymerization. Experimental investigations show that the particle size increased with decreasing emulsifier concentrations and increasing monomer/water ratios or electrolyte concentrations. The latex particle coagulation was considered as the dominant particle formation and growth method, which could be proved by the evolutions of particle number as well as dimension against conversion. Latex particle coagulation occurred if the particle surface covered ratio dropped between the critical surface covered ratio (θ crit = 0.59) and the lowermost surface covered ratio (θ low = 0.38). In addition,θ crit and θ low were increased with electrolyte concentrations.

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).