Soapless Emulsion Polymerization Research Articles

Investigating the effect of the perturbation on emulsion polymerization of polystyrene nanospheres

Polystyrene nanospheres (PS spheres) were prepared by soap-less emulsion polymerization. The polymerization reaction with the monomer styrene was initiated using potassium persulfate under nitrogen injection. By adjusting the amount of precursor and the mixing speed of the stirrer during the polymerization process, PS particles of the expected appropriate size can be obtained. This work focuses on the effect of precursor concentration, reaction conditions and stirrer speed on particle size. Samples (C1–C6) were systematically prepared with varying amounts of K2S2O8 and C8H8. The particle sizes ranged from 69.9[Formula: see text]nm to 364.44[Formula: see text]nm. The calculated K2S2O8 to C8H8 ratio remained approximately constant across the samples. This supports the observed trend where increasing monomer concentration leads to larger particle sizes, indicative of bonded spheres. In addition, a correlation between stirring speed and PS bead size is found, with higher speeds resulting in smaller particles. Transmittance analysis of the filtered and sieved process samples showed that better polymerization conditions could be selected for PS beads up to 220[Formula: see text]nm at a stirring speed of 900[Formula: see text]rpm.

Preparation of multi-responsive amphiphilic particles by one-step soapless emulsion polymerization

A novel multi-responsive amphiphilic copolymer (mRAP) particles with tunable emulsifiability was successfully prepared via one-step soapless emulsion polymerization using common monomers, such as methyl methacrylate, methacrylic acid (MAA), butyl acrylate (BA) and N,N-diethylacrylamide (DEAA). The obtained monodisperse spherical mRAP particles were characterized by dynamic light scattering, Fourier transform infrared spectroscopy, scanning electron microscope and transmission electron microscope, which provided the information of particle size, components and anisotropic structure. Its multiple responsivities were investigated under the condition of diversified pH values, salinity and temperature. The results showed that the mRAP particles exhibited good dispersivity based on uniform particle size, as well as tunable emulsifiability and anticipated multiple responsiveness. Furthermore, the tunable emulsifiability of oil–water mixtures could be easily achieved by adjusting the mass ratios of MAA to DEAA. Meanwhile, the obtained multi-responsive polymers relying on simple and effective copolymerization can be used in fundamental research and industrial production.

Temperature- and pH-sensitive core–shell nanogels as efficient carriers of doxorubicin with potential application in lung cancer treatment

ABSTRACTTemperature- and pH-sensitive core–shell nanogels were prepared by one-pot soapless emulsion polymerization of N-isopropylacrylamide and 2-methacryloyloxy benzoic acid with the aid of a crosslinker (core) using poly(ethylene glycol) methyl ether methacrylate as stabilizer (shell). The size of nanogels depended on the crosslinker used, being considerable smaller (around 100 nm) with the use of the acid-labile crosslinker 9-divinyl-2,4,8,10-tetraoxaspiro[5.5]-undecane (DVA). Doxorubicine (DOX) was loaded in nanogels with good efficiency. The empty nanogels were biocompatible for a lung cancer cell line (NCI-H1437), while the DOX-loaded, DVA-crosslinked nanogels resulted with efficient cytotoxicity for that cell line.

Successive growth and applications of polymeric particles with controllable size and shapes

Nonspherical particles resembling sea pineapples were synthesized by successive growth technique during soapless emulsion polymerization for various applications. First, highly cross-linked seed particle dispersion was synthesized by emulsifier-free emulsion polymerization with acrylic acid as co-monomer for the formation of surface carboxylic groups. Then, a successive growth scheme was applied to the seeds by swelling the particles with monomer droplets, followed by polymerization. The sea pineapple-shaped particles could be produced by adjusting the amount of monomer during the swelling step of the third growth. As a demonstrative application, the seed or sea pineapple-shaped particles could be used as templates for the synthesis of porous inorganic particles by spray drying technique. The resulting porous particles could be adopted as photocatalyst for the decomposition of organic molecules such as methylene blue. As another application, the dye molecules could be adsorbed onto the second grown particles to produce dye-doped nanospheres. Finally, the sea pineapple-shaped particles could be self-organized into supra-aggregates using toluene emulsions as confining geometries. Collectively, successively grown particles were found to be efficient building blocks to prepare the unusually packed structures or functionalized into colored products.

Synthesis of Latex Particles with Surface Functional Groups and Their Applications for the Fabrication of Porous Materials

In this study, monodisperse latex particles with specific surface functional groups were synthesized by emulsifier-free emulsion polymerization. Amidine or carboxylated polystyrene nanospheres with narrow size distribution were prepared by emulsion polymerization using AIBA (α,α′-zodiisobutyramidine dihydrochloride) as amine-containing initiator or acrylic acid as carboxyl-containing comonomer, respectively. Factors affecting the particle size and distribution were systemically studied by changing the amount of initiator or monomer, the polymerization temperature, and the stirring speed of emulsion polymerization reactor. Monodisperse polymethylmethacrylate beads were also synthesized by soapless emulsion polymerization using methacrylic acid or aminoethylmethacrylate hydrogen hydrochloride as comonomer for the surface functionalization of the particles. As applications of the latex beads, the polymeric particles were adopted as templating materials for the fabrication of macroporous titania film and meso-macroporous silica particles by colloidal templating method.

Synthesis and characteristics of poly(methyl methacrylate‐co‐methacrylic acid)/poly(methacrylic acid‐co‐N‐isopropylacrylamide) thermosensitive semi‐hollow latex particles and their application to drug carriers

ABSTRACTIn this work, the poly(methyl methacrylate‐co‐methacrylic acid)/poly(methacrylic acid‐co‐N‐isopropylacrylamide) thermosensitive composite semi‐hollow latex particles was synthesized by three processes. The first process 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 process was to polymerize methacrylic acid (MAA), N‐isopropylacrylamide (NIPAAm), and crosslinking agent, 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 with solid structure. In the third process, part of the linear poly(MMA‐MAA) core of core–shell latex particles was dissolved by ammonia to form the poly(MMA‐MAA)/poly(MAA‐NIPAAm) thermosensitive semi‐hollow latex particles. The morphologies of the semi‐hollow latex particles show that there is a hollow zone between the linear poly(MMA‐MAA) core and the crosslinked poly(MAA‐NIPAAm) shell. The crosslinking agent and shell composition significantly influenced the lower critical solution temperature of poly(MMA‐MAA)/poly(MAA‐NIPAAm) semi‐hollow latex particles. Besides, the poly(MMA‐MAA)/poly(MAA‐NIPAAm) thermosensitive semi‐hollow latex particles were used as carriers to load with the model drug, caffeine. The processes of caffeine loaded into the semi‐hollow latex particles appeared four situations, which was different from that of solid latex particles. In addition, the phenomenon of caffeine released from the semi‐hollow latex particles was obviously different from that of solid latex particles. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3441–3451

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

A Laser-Imageable Thin Coating Derived from Polymer Nano-particles Containing Infrared Dye

This study is focused on a water-born thermo-sensitive material composition based on an infrared (IR)-sensitive (830nm) polymer nano-particles and the potentiality in preparation of environment-friendly CTP plate. Polymer nano-particles containing IR-absorbing dye (IR nano-particles) were prepared through soapless emulsion polymerization in the presence of active emulsifier and a redox initiation system. A water soluble polymer, poly (N-hydroxymethyl acrylamide) (PHMA), was used as the binder resin. An IR laser-imageable coating was prepared with the above materials as the main components. Upon laser exposure, the IR dye of the polymer particles absorbed IR energy and produced high temperature, leading the particles to be fused and causing great changes in both surface morphology and inner structure of the coating. As a result, the exposed areas were no longer water-soluble or water-dispersible, whereas the unexposed areas remained unchanged and were still soluble or dispersible in water. When developing with water, negative images would be obtained.

Preparation and Properties of Anionic Polymer Emulsion in the Presence of a Reactive Surfactant

Stable polymer emulsion derived from Butyl Methacrylate (BMA), 4-vinyl pyridine (4-VP), vinylidene chloride (VDC) and divinylbenzene (DVB) with different size and distribution were prepared through soapless emulsion polymerization by using a reactive surfactant and a redox initiator. The influences of the quality ratio of the reactive surfactant to the monomers and the dosages of the cross-linking agent on the stability and thermal properties of the emulsion were studied. The obtained polymer nano-particles have higher ξ potential, and the particle sizes have narrow distribution. This polymerization system can give some further understanding on the mechanism of emulsion polymerization .The solid content of the emulsion could be as high as 40% and the particle sizes could be adjusted in the range of 40-300nm. Otherwise, using infrared spectroscopy, size and ξ analyzer, gravitational thermal analysis and differential scanning calorimeter, properties of the emulsion latex were tested. This kind of latex may have applications in the development of water-developable thermal-sensitive material system.

Synthesis and characteristics of poly(methyl methacrylate-methacrylic acid-3,3-(trimethoxysilyl) propyl methacrylate) hollow latex particles and their application to drug carriers

In this study, the hollow latex particle was synthesized by three processes. The first process was to synthesize the poly(methyl methacrylate-co-methacrylic acid) (poly(MMA-MAA)) copolymer latex particles by the method of soapless emulsion polymerization. Following the first process, the second process was to polymerize MMA, MAA, 3,3-(trimethoxysilyl) propyl methacrylate (MPS), and ethylene glycol dimethacrylate in the presence of poly(MMA-MAA) latex particles to form the linear poly(MMA-MAA)/crosslinking poly(MMA-MAA-MPS) core–shell latex particles. In the third process, the core–shell latex particles were heated in the presence of ammonia to form the poly(MMA-MAA-MPS) hollow latex particles. A sufficient heating time and high-heating temperature were necessary for the ammonia to dissolve the linear poly(MMA-MAA) core to form a perfect hollow structure. The crosslinking poly(MMA-MAA-MPS) shell was a barrier for the ammonia to diffuse into the latex particles so that the latex particle with the high-crosslinking shell showed an imperfect hollow structure. Besides, the hollow poly(MMA-MAA-MPS) latex particles reacted with ZnO nanoparticles, which were synthesized by a traditional sol-gel method, to form the polymer/inorganic poly(MMA-MAA-MPS)/ZnO composite hollow latex particles. With the increase of crosslinking degree would increase the amount of ZnO bonding. Moreover, the poly(MMA-MAA-MPS) hollow latex particles were used as carriers to load with the model drug, caffeine. The release of caffeine from poly(MMA-MAA-MPS) hollow latex particles was investigated.

Synthesis and characteristics of poly(N -isopropylacrylamide-co -methacrylic acid)/Fe3 O4 thermosensitive magnetic composite hollow latex particles

In this study, the poly(NIPAAm–MAA)/Fe3O4 hollow latex particles were synthesized by three steps. The first step was to synthesize the poly(methyl methacrylate-co-methylacrylate acid) (poly(MMA-MAA)) copolymer latex particles by the method of soapless emulsion polymerization. Following the first step, the second step was to polymerize N-isopropylacrylamide (NIPAAm), MAA, and crosslinking agent (N,N'-methylene-bisacrylamide (MBA)) in the presence of poly(MMA-MAA) latex particles to form the linear poly(MMA-MAA)/crosslinking poly (NIPAAm-MAA) core-shell latex particles. After the previous processes, the core-shell latex particles were heated in the presence of NH4OH to dissolve the linear poly(MMA-MAA) core in order to form the poly(NIPAAm-MAA) hollow latex particles. In the third step, Fe2+ and Fe3+ ions were introduced to bond with the COOH groups of MAA segments in the poly(NIPAAm-MAA) hollow polymer latex particles. Further by a reaction with NH4OH and then Fe3O4 nanoparticles were generated in situ and the poly(NIPAAm-MAA)/Fe3O4 magnetic composite hollow latex particles were formed. The concentrations of MAA, crosslinking agent (N,N'-methylene bisacrylamide), and Fe3O4 nanoparticles were important factors to influence the morphology of hollow latex particles and lower critical solution temperature of poly(NIPAAm–MAA)/Fe3O4 magnetic composite hollow latex particles. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Preparation and properties of soapless poly(styrene–butyl acrylate–acrylic acid)/SiO2 composite emulsion

Soapless emulsion polymerization of styrene-butyl acrylate-acrylic acid was carried out using single or combined polymerizable emulsifiers, such as hydroxypropyl methacrylate sodium sulfate (HPMAS), sodium vinyl sulfate, and vinyl alkylphenol polyether sulfates (NRS-10), in the presence of colloidal nano-SiO2 solution in order to obtain films with high degree of hardness and water-resistance. Monomer conversion, formation of coagulum, viscosity, particle size, size distribution, and surface tension of the emulsions, as well as the film properties, were determined and compared with those of an emulsion prepared with the conventional emulsifier sodium dodecyl sulfate and polyoxyethylene octylphenol ether. Emulsions prepared from a mixture of two polymerizable emulsifiers NRS-10 and HPMAS (1:1, weight ratio) have presented high monomer conversion, low coagulum, and small particle sizes. When the emulsifier level increased within a certain level, the monomer conversion increased but particles size decreased. Increased amounts of reactive emulsifiers led to low monomer conversion, large amount of coagulum and small particle sizes. With the increase of nano-SiO2 the particle sizes and the viscosity of the emulsion also increased. The introduction of reactive emulsifiers improved the water-resistance of the resulting films, and the addition of nano-SiO2 increased the hardness of the coatings. Under optimal conditions, the coatings made from emulsions produced from a combination of reactive emulsifiers such as NRS-10 and HPMAS (1:1, weight ratio) at 2 % level (based on monomer weight) exhibited remarkable hardness, adhesion force and water-resistance.

Synthesis and characteristics of poly(methacrylic acid–co–N-isopropylacrylamide)/Nano ZnO thermosensitive composite hollow latex particles

In this work, the poly(methacrylic acid–co–N-isopropylacrylamide)/Nano ZnO thermosensitive composite hollow latex particles was synthesized by three processes. The first process 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 process was to polymerize MAA, N-isopropylacrylamide (NIPAAm) and N,N′-Methylenebisacrylamide (MBA) in the presence of poly(MMA–MAA) latex particles to form the linear poly(MMA–MAA)/crosslinking poly(MAA-NIPAAm) core–shell latex particles, and then the core–shell latex particles were heated in the presence of ammonia solution to form the poly(MAA-NIPAAm) thermosensitive hollow latex particles. In the third process, the poly(MAA-NIPAAm) hollow latex particles reacted with ZnO nanoparticles to form the poly(MAA-NIPAAm)/ZnO thermosensitive composite hollow latex particles on which the ZnO nanoparticles were adsorbed. Besides, a novel process was used to synthesize the poly(MAA-NIPAAm)/ZnO composite latex particles in which the ZnO nanoparticles were encapsulated. The effects of various variables on the morphology of poly(MAA-NIPAAm)/ZnO composite hollow latex particle were studied.

Preparation of Bead–String Shaped Attapulgite/Poly(methyl methacrylate) Particles by Soapless Emulsion Polymerization Based on UV Irradiation in the Presence of Iron(III)

Bead–string shaped attapulgite/poly(methyl methacrylate) (ATP/PMMA) nanocomposite particles were prepared by soapless emulsion polymerization based on UV irradiation. Two steps were used to encapsulate attapulgite (ATP) by poly(methyl methacrylate) (PMMA). Firstly, the pretreatment of attapulgite with cetyltrimethylammonium bromide (CTAB) in ultrasonic was essential for successful encapsulation and for creating strong interfacial interaction between ATP and PMMA. Then PMMA was photopolymerized on the surface of ATP with FeCl3 as photoinitiator. The products were characterized by FT-IR, TGA, TEM, SEM and XRD. The results showed that bead–string shaped ATP/PMMA has been formed in this method. TEM and XRD results revealed the addition of PMMA did not change the crystal structure of attapulgite. The mechanisms of the process of organo-ATP with double-layered or monolayered CTAB structures and the synthesis process of ATP/PMMA shell/core composites with bead–string morphology have been discussed. The photopolymerization initiated by FeCl3 presented high efficiency even though using a small percentage of photoinitiator.

Preparation of a Cross-linkable Emulsion and its Effectiveness as the Binder Resin of Water-based Printing inks Curable at Ambient Temperature

The proposed resin system mainly comprises two components: a nano-sized emulsion and a crosslinking agent, adipic dihydrazide. The nano-emulsion was prepared through soapless emulsion polymerization of acrylic monomers in the presence of a reactive amphiphillic block copolymer, which was synthesized through living polymerization of diacetone acrylamide and acrylic acid. The nano-emulsion was narrowly distributed in size and the average diameter is around 50 nm. The nano-emulsion was very stable even at 45 wt.%. DSC analysis showed that the polymer of the emulsion had a low glass transition temperature (Tg) (about 15 °C), but the emulsion still remained stable at a wide temperature range (4-50 °C) despite the addition of the cross-linker. Emulsion films were coated with the mixture of the nano-emulsion, the cross-linker and a small amount of leveling agent by spin-coating method, and this was followed by drying at ambient temperature. SEM analysis indicated that the border of particles had disappeared and a uniform film was obtained. Investigation on dissolution behaviors of the emulsion films showed that cross-linking reaction occurred with the evaporation of water. With the drying of the film at ambient temperature, a tough and transparent cross-linked film was prepared, which had good water/solvent resistance. This self-crosslinking resin system might be used as the binder resin for water-based printing inks which can be effectively cured at ambient temperature.

Synthesis of pH and temperature sensitive, core–shell nano/microgels, by one pot, soap-free emulsion polymerization

The synthesis and properties of thermal/pH-sensitive core–shell copolymer nano/microgels were investigated. The crosslinked core consisted of N-isopropylacrylamide (NIPAAm) while the shell was stabilized by poly(ethylene glycol) methyl ether methacrylate (PEGMA) and 2-methacryloyloxybenzoic acid (2MBA) using a “one pot” soapless emulsion polymerization method. Monodisperse particles were produced with average hydrodynamic diameters ranging from 40 to 880nm, as determined by dynamic light scattering (DLS) in water at 25°C, depending on the synthetic recipe used. The influence of PEGMA and 2MBA content on size and temperature transition at different pH values was studied. Zeta potential measurements and acid–base titration studies demonstrated almost complete incorporation of acid comonomer (2MBA) into the nano/microgels. Two different crosslinkers, a stable and an acid labile, were compared. The crosslinker used has a major influence on the size and charge density of the nano/microgels produced. Microscopic studies confirmed the core–shell morphology of the nano/microgels.

Synthesis and Characterization of Polyacrylonitrile Microspheres by Soapless Emulsion Polymerization

Polyacrylonitrile(PAN) microspheres were synthesized by soapless emulsion polymerization of acrylonitrile(AN) in water. The effects of monomer and initiator concentration on the conversion of AN and the diameter of microspheres were investigated. The results showed that when the concentration of monomer increases, the conversion of AN decreases while the diameter of PAN microspheres increases. When the concentration of initiator increases, the conversion of AN and the diameter of PAN microspheres both increase. For this method of PAN microspheres synthesis, the highest conversion of AN is about 60% and the diameter can be controlled in need ranging from approximately 140 to 500nm.

Synthesis and friction properties of copper/PMMA composites by soapless emulsion polymerization

AbstractCopper (Cu)‐doped polymethylmethacrylate (PMMA) composites were prepared by soapless emulsion polymerization. In this process, copper nanoparticles were modified by sodium oleate (SOA) and the surface property of Cu nanoparticles changed from hydrophilic to hydrophobic. The hydrophobic Cu nanoparticles could not only avoid the oxidation of Cu in air but also improve the compatibility between Cu nanoparticles and PMMA. The TEM micrographs revealed that Cu nanoparticles were encapsulated in PMMA polymer microspheres. In addition, the uniform Cu/PMMA composite microspheres could be synthesized in such a soapless emulsion polymerization process. It was worth mentioning that the friction property in oil was well improved when little nanocomposites were added into the base oil, which indicated that the composites can be widely used in lubricating oil. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The preparation and characteristics of poly(methyl methacrylate–methylacrylate acid)/nano-ZnO composite latex particles

In this work, poly(methyl methacrylate-co-methylacrylate acid)/ZnO (poly(MMA–MAA)/ZnO) composite latex particle was synthesized by three steps The first step was to synthesize poly(MMA–MAA) copolymer latex particles by soapless emulsion polymerization. Following the first step, the second step was to polymerize MMA, MAA and 3,3-(trimethoxysilyl) propyl methacrylate (MPS) in the presence of poly(MMA–MAA) seed latex particles to form the poly(MMA–MAA)/poly(MMA–MAA–MPS) core–shell latex particles. In the third step, the poly(MMA–MAA)/poly(MMA–MAA–MPS) latex particles reacted with ZnO nanoparticles, which were synthesized by a traditional sol gel method, to form the polymer/inorganic poly(MMA–MAA)/poly(MMA–MAA–MPS)/ZnO composite latex. In this study, MPS with silanol groups essentially was used as the coupling agent to couple with ZnO nanoparticles, while the results of the study showed that there was not covalent bond existed between ZnO particles and polymer latex. The ZnO particles were adsorbed on the surface of polymer latex by electrostatic interaction. Besides, the linear poly(MMA–MAA)/crosslinking poly(MMA–MAA–MPS) core–shell latex particles which were synthesized in the second step were heated in the presence of ammonia to form the hollow poly(MMA–MAA–MPS) latex particles. The factors of heating time and concentration of crosslinking agent significantly influenced the morphology of hollow poly(MMA–MAA–MPS) latex particles.

Synthesis of monodispersed crosslinked nanoparticles decorated with surface carboxyl groups via soapless emulsion polymerization

The preparation conditions of the monodispersed crosslinked polystyrene nanoparticles decorated with surface carboxyl groups via soapless emulsion polymerization with oleic acid (OA) as emulsifying comonomer (surfmer) and divinyl benzene (DVB) as crosslinker were optimized in the present work. The effects of the amounts of surfmer, crosslinker and initiator added, polymerization time on the particle sizes of the nanoparticles were investigated by the dynamic laser light scattering (DLS) analysis. Monodispersed functional crosslinked polystyrene nanoparticles with the particle size near 250 nm were obtained for the optimum polymerization condition.