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Emulsion Copolymerization (emulsion + copolymerization)

Distribution by Scientific Domains
Polymers and Materials Science100%

Kinds of Emulsion Copolymerization

  • emulsifier-free emulsion copolymerization
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    Selected Abstracts

    Emulsifier-Free Emulsion Copolymerization of Vinyl Acetate and 3-Dimethyl(methacryloyloxyethyl)ammonium Propanesulfonate and Swelling Behavior of their Copolymer Matrices

    MACROMOLECULAR REACTION ENGINEERING, Issue 5 2007
    Elena Kamenska
    Abstract Stable poly{(vinyl acetate)- co -[3-dimethyl(methacryloyloxyethyl)ammonium propanesulfonate]} latexes with different compositions were synthesized by emulsifier-free emulsion copolymerization. An unusual "overshooting" behavior of the copolymer tablets is explained based on the formation of specific clusters of oppositely oriented dipoles. The variation of their concentration with the zwitterionic monomer unit fraction, ionic strength and temperature is responsible for the differences in the swelling kinetics established. The results show that these parameters can be used to control swelling degree of copolymer matrices and their sustained drug delivery. [source]

    Emulsion copolymerization of styrene and sodium styrene sulfonate: kinetics, monomer reactivity ratios and copolymer properties

    POLYMER INTERNATIONAL, Issue 1 2009
    Dhamodaran Arunbabu
    Abstract BACKGROUND: The synthesis of poly[styrene- co -(sodium styrene sulfonate)], poly(S- co -NaSS), with a high loading of sulfonate groups is of current interest owing to its potential use in numerous areas. A series of these copolymers with various sulfonate loads were synthesized using the emulsion polymerization technique with a study of the copolymerization kinetics, monomer reactivity ratio and copolymer properties. RESULTS: The copolymerization kinetics are significantly enhanced with an increase of NaSS feed in the polymerization. Monomer reactivity ratios were determined from NMR data by employing the Fineman,Ross and Kelen,Tüdös methods. Styrene (r1) and NaSS (r2) reactivity ratios are 0.5 and 10, respectively. The colloidal particle size of the copolymers depends upon the NaSS composition. The thermal stability of the copolymers is greatly enhanced with higher NaSS content in the copolymer backbone. Higher glass transition temperatures are observed for the copolymers with higher NaSS content. CONCLUSION: The reactivity ratio values suggest that styrene prefers to form copolymers whereas NaSS produces homopolymers. It is also found that styrene copolymerization with NaSS is only twice as fast as homopolymerization. In contrast, NaSS homopolymerization is ten times faster than NaSS copolymerization with styrene. The NaSS content in the copolymer backbone affects the thermal stability and the glass transition of the copolymers. Copyright © 2008 Society of Chemical Industry [source]

    Effect of the carboxylic acid monomer type on the emulsifier-free emulsion copolymerization of styrene and butadiene

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2007
    Mahdi Abdollahi
    Abstract Carboxylated styrene,butadiene rubber latexes were prepared through the emulsifier-free emulsion copolymerization of styrene and butadiene with various carboxylic acid monomers. The effects of various carboxylic acid monomers on the particle formation process were investigated. The type of carboxylic acid monomer strongly affected the particle nucleation. The number of particles and thus the polymerization rate increased with the increasing hydrophobicity of the carboxylic acid monomers. There was a significant difference in the polymerization rate per particle. The results showed that particle nucleation and growth were dependent on the hydrophilic nature of the carboxylic acid monomers. The average particle diameter of the carboxylated styrene,butadiene rubber latexes in the dry state was obtained through some calculations using direct measurements of the average particle diameter in the monomer-swollen state by a dynamic light scattering technique. Several parameters, such as the polymerization rate, number of latex particles per unit of volume of the aqueous phase, and polymerization rate per particle, were calculated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [source]

    Morphology and temperature responsiveness,swelling relationship of poly(N -isopropylamide,chitosan) copolymers and their application to drug release

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 12 2004
    Chia-Fen Lee
    Abstract Poly [N -isopropylacrylamide (NIPAAm),chitosan] crosslinked copolymer particles were synthesized by soapless emulsion copolymerization of NIPAAm and chitosan. An anionic initiator [ammonium persulfate (APS)] and a cationic initiator [2,2,-azobis(2-methylpropionamidine)dihydrochloride (AIBA)] were used to initiate the reaction of copolymerization. The chitosan,NIPAAm copolymer synthesized by using APS as the initiator showed a homogeneous morphology and exhibited the characteristic of a lower critical solution temperature (LCST). The copolymer synthesized by using AIBA as an initiator showed a core,shell morphology, and the characteristic of LCST was insignificant. The LCST of the chitosan,NIPAAm copolymer depended on the morphology of the copolymer particles. In addition, the chitosan,NIPAAm copolymer particles were processed to form copolymer disks. Then, the effect of various variables such as the chitosan/NIPAAm weight ratio, the concentration of crosslinking agent, and the pH values on the swelling ratio of chitosan,NIPAAm copolymer disks were investigated. Furthermore, caffeine was used as the model drug to study the characteristics of drug loading of the chitosan,NIPAAm copolymer disks. Variables such as the chitosan/NIPAAm weight ratio and the concentration of the crosslinking agent significantly influenced the behavior of caffeine loading. Two factors (pore size and swelling ratio) affected the behavior of caffeine release from the chitosan,NIPAAm copolymer disks. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3029,3037, 2004 [source]

    Principle of a New Immunoassay Based on Electrophoretic Mobility of Poly(styrene/, - tert -butoxy- , -vinylbenzyl-polyglycidol) Microspheres: Application for the Determination of Helicobacter pylori IgG in Blood Serum

    MACROMOLECULAR BIOSCIENCE, Issue 1 2005
    Teresa Basinska
    Abstract Summary: The principle of a novel latex diagnostic test for the determination of antibodies against Helicobacter pylori in blood sera is described. The test is based on the measurement of the electrophoretic mobility of the microspheres with immobilized H. pylori antigens. The electrophoretic mobility of these microspheres depends on the concentration of the antibodies against H. pylori in suspending medium. Particles with hydrophilic polyglycidol in the surface layer were used for the test. The microspheres were obtained by an emulsifier-free emulsion copolymerization of styrene and , - tert -butoxy- , -vinylbenzyl-polyglycidol macromonomer (,=,220 nm, diameter polydispersity factor ,=,1.02). Activation of polyglycidol hydroxyl groups with cyanuric chloride allowed for covalent immobilization of H. pylori antigens. The fraction of H. pylori not specifically adsorbed onto the microspheres was negligible. Changes of the electrophoretic mobility of the microspheres with the surface concentration of the covalently immobilized H. pylori antigens ,,=,(1.6,±,0.3),·,10,3 g m,2 were suitable for the detection of the antibodies in the sera of patients with titer in the range (determined by the indirect ELISA test) from 1:500 to 1:32,000. [source]

    Unexpected Crosslinking During Acetoacetoxy Group Protection on Waterborne Crosslinkable Latexes

    MACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2006
    Ińigo González
    Abstract Summary: The microstructure of the polymer synthesized by seeded semicontinuous emulsion copolymerization of AAEMA was investigated. It was found that the neutralization of the latexes with ammonia to protect acetoacetoxy functionality against hydrolysis during storage had a remarkable effect on the gel content. A base catalyzed Michael addition reaction between acetoacetoxy groups and terminal double bond (TDB) is proposed as responsible for the chain precrosslinking observed. The presence of TDB in the latexes was demonstrated by means of 1H NMR. Moreover, the chain precrosslinking affected the subsequent crosslinking reaction of the latex with diamines hindering chain interdiffusion and yielding poorer mechanical properties. Michael addition between AcAc functional groups and TDB, and final gel content of the MMA/BA/MAA latexes with different amounts of AAEMA. [source]

    Emulsifier-Free Emulsion Copolymerization of Vinyl Acetate and 3-Dimethyl(methacryloyloxyethyl)ammonium Propanesulfonate and Swelling Behavior of their Copolymer Matrices

    MACROMOLECULAR REACTION ENGINEERING, Issue 5 2007
    Elena Kamenska
    Abstract Stable poly{(vinyl acetate)- co -[3-dimethyl(methacryloyloxyethyl)ammonium propanesulfonate]} latexes with different compositions were synthesized by emulsifier-free emulsion copolymerization. An unusual "overshooting" behavior of the copolymer tablets is explained based on the formation of specific clusters of oppositely oriented dipoles. The variation of their concentration with the zwitterionic monomer unit fraction, ionic strength and temperature is responsible for the differences in the swelling kinetics established. The results show that these parameters can be used to control swelling degree of copolymer matrices and their sustained drug delivery. [source]

    Synthesis and characterization of poly(butyl acrylate- co -ethylhexyl acrylate)/ poly(vinyl chloride)[P(BA-EHA)/PVC] novel core-shell modifier and its impact modification for a poly(vinyl chloride)-based blend

    POLYMER ENGINEERING & SCIENCE, Issue 6 2010
    Mingwang Pan
    Synthesis of poly(butyl acrylate-co-ethylhexyl acrylate)-core/poly(vinyl chloride)-shell [P(BA-EHA)/PVC] used as a modifying agent of PVC via semicontinuous seeded emulsion copolymerization is reported here. Diameter distributions and morphology of the composite latex particles were characterized with the aid of particle size analyzer and transmission electron microscopy (TEM). The grafting efficiency (GE) and grafting ratio (GR) of vinyl chloride (VC) grafted onto the P(BA-EHA) with varying content of crosslinking agent and core-shell ratios were investigated. TEM studies indicated that the P(BA-EHA)/PVC latex particles have core-shell structure, and the P(BA-EHA) rubbery particles in blending materials were uniformly dispersed in PVC matrix. Dynamic mechanical analysis (DMA) results revealed that the compatibility between the P(BA-EHA) and the PVC matrix was significantly improved due to the presence of the P(BA-EHA)-grafted-VC copolymer. The notched impact strength of the blending material with 3 wt% of rubber content was seven times that of the PVC. Linear regressions of mechanical properties as loading of the modifier were made. The resulting data of notched impact strength and elongation at break for the blending materials deviated significantly from regression lines within 3,4.5 wt% of the P(BA-EHA) content. The PVC blends modified by the modifier exhibited good toughness and easy processability. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source]

    Preparation and Biodegradation of Sugar-Containing Poly(vinyl acetate) Emulsions

    MACROMOLECULAR BIOSCIENCE, Issue 2 2008
    Akinori Takasu
    Abstract To accelerate the biodegradability of poly(vinyl acetate)-based emulsions, emulsion copolymerizations of vinyl sugars, including triacetylated N -acetyl- D -glucosamine (GlcNAc)-substituted 2-hydroxyethyl methacrylate (GlcNAc(Ac)3 -substituted HEMA), glucose-substituted HEMA (GEMA) and 6- O -vinyladipoyl- D -glucose (6- O -VAG) with vinyl acetate (VAc), were carried out using poly(vinyl alcohol) as an emulsifying agent in the presence of poly[(butylene succinate)- co -(butylene adipate)] [poly(BS- co -BA)]. Copolymerization with GEMA produced a stable emulsion and that with 6- O -VAG also produced a homogeneous emulsion. Their biodegradation tests indicated that PVAc main chain scission was accelerated by copolymerization with vinyl sugars. [source]