Polystyrene latex particles bearing primary amine groups via soap‐free emulsion polymerization (original) (raw)
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Journal of Polymer Science Part A: Polymer Chemistry, 2005
Monodisperse latex particles with different amounts of surface amino and amidine groups were synthesized by means of a semicontinuous seeded cationic emulsion polymerization of styrene and a cationic monomer. High partial overall conversions for styrene and limited ones for the cationic monomer were achieved. A reliable method for the quantification of surface amidine and amino groups was developed. It was found that the amount of surface amidine groups provided by the cationic initiator was higher when the amount of cationic monomer added increased. The value for the partition coefficient of the cationic monomer indicated that this polymerizes with the same probability in the water phase as in the particle. The colloidal stability, in terms of critical coagulation concentration, shows that the latexes would be useful as polymeric supports in immunoassays. V
Modeling the emulsion polymerization of amino-functionalized latex particles
Polymer, 2006
A mathematical model for a semicontinuous seeded cationic emulsion polymerization was developed. The model includes the most distinctive features of the copolymerization of a cationic hydrophilic monomer with a hydrophobic one, including polymerization of the hydrophilic monomer in the outer shell of polymer particles and in the aqueous phase, and the possibility of having radical concentration profiles in the polymer particles. The reactions were carried out by means of a semicontinuous seeded cationic emulsion polymerization under starved conditions for styrene, which was the main monomer employed. The model predicts the evolution of the fractional overall conversions, the thickness of the outer shell, the total surface charge density and the partial conversions for the semicontinuous seeded cationic emulsion polymerization of styrene and aminoethyl methacrylate hydrochloride. Furthermore, the model can distinguish between the surface charge density provided by the cationic monomer than that given by the cationic initiator. Therefore, this model can predict the best conditions to obtain well-defined latexes with specific amounts of surface amino and amidine groups useful for immunoassays.
Synthesis of amino-functionalized latex particles by a multistep method
Journal of Polymer Science Part A: Polymer Chemistry, 2001
Cationic latex particles with surface amino groups were prepared by a multistep batch emulsion polymerization. In the first one or two steps, monodisperse cationic latex particles to be used as the seed were synthesized, and in the third step, two different amino-functionalized monomers [aminoethylmethacrylate hydrochloride (AEMH) and vinylbenzylamine hydrochloride (VBAH)] were used to synthesize the final functionalized latex particles. 2,2Ј-Azobisisobutyramidine dihydrochloride was used as the initiator, and different concentrations of two quaternary ammonium emulsifiers with hydrophobic chains of different lengths were examined. To characterize the final latexes yields were obtained gravimetrically, and particle size distributions and average particle diameters were determined by transmission electron microscopy and photon correlation spectroscopy. The amount of amino groups was determined by fluorimetry. The effect of the amino-functional monomer used on the final latexes and the colloidal behavior of the system were studied. The influence of the different conditions utilized to synthesize the latexes on the colloidal stability of the particles was evaluated in terms of the Fuchs stability ratio and electrophoretic mobility. High yields of the amino-functional monomers were obtained. Surface amino, amidine, and quaternary ammonium groups provided the cationic character. The colloidal stability behavior of the products obtained was compatible with their cationic character.
Acetal-functionalized polymer particles useful for immunoassays
Journal of Polymer Science Part A-polymer Chemistry, 1997
The synthesis of core-shell type polystyrene monodisperse particles with surface acetal groups was carried out by a two-step emulsion polymerization process. In a first step, the core was synthesized by batch emulsion polymerization of styrene (St), and in the second step, the shell was polymerized by batch emulsion terpolymerization of styrene, methacrylic acid (MAA), and methacrylamidoacetaldehyde dimethyl acetal (MAAMA), using the seed obtained previously. With the aim of analyzing the effect of the thickness of the shell, the pH of the reaction medium and the weight ratio of the termonomers to prepare the shell, on the amount of the functionalized groups, several core-shell type latex particles were synthesized by two-step emulsion polymerization in a batch reactor. The latexes were characterized by TEM and conductimetric titration to obtain the particle size distribution and the amount of carboxyl and acetal groups on the surface, respectively. Looking for the applicability of the synthesized latexes in immunoassays, IgG a-CRP rabbit antibody was covalently bonded to the surface of the particles synthesized in neutral medium. The complex latex-protein was immunologically active against the CRP antigen.
Immobilization of proteins onto novel, reactive polypyrrole-coated polystyrene latex particles
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2004
Polypyrrole-coated polystyrene latex particles bearing reactive N-ester succinimidyl functional groups (PS-PPyNSE) were prepared by the in situ copolymerization of pyrrole (Py) and the ester-functionalized pyrrole (pyrrole-NSE) in the presence of sterically stabilized polystyrene (PS) latex particles (∼600 nm). The initial comonomer fractions (in %) were 25/75, 40/60, 50/50, 75/25 and 85/15 for pyrrole-NSE and pyrrole, respectively. The PS-PPyNSE particles were characterized in terms of particle size, surface morphology and surface chemical composition. The reactivity of the particles towards ethylenediamine and human serum albumin (HSA) was examined by FTIR, which unambiguously indicated the formation of interfacial amide groups.
Polymer Journal, 2002
Amphiphilic poly(ethylene glycol)-b-polylactide (PEG/PLA) block macromonomers with an aldehyde group at the PEG chain end and a methacryloyl group at the PLA chain end were quantitatively synthesized by anionic polymerization. PEGylated latex particles were then prepared by dispersion radical copolymerization of the PEG/PLA block macromonomer with styrene in water. PEG/PLA macromonomer itself works as a surfactant to stabilize styrene droplets in the copolymerization process. Acetal groups at the PEG chain end on the latex particle were quantitatively converted to aldehyde groups by an acid treatment. In this way, polystyrene latex particles covered with PEG tethered chains possessing an aldehyde end-group were obtained. The size of the latex was quantitatively controlled ranging in size from 56 nm to 235 nm by the amount of the block macromonomer. The number of aldehyde groups on the latex particle was estimated to be approximately 0.029 molecules nm −2 by electric spin resonance (ESR) using 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as a probe. Regardless of the size of the latex particles synthesized in this study, the occupied area of 4-amino-TEMPO on the particle was constant. Biotin was then introduced in a distal end of PEG-strands as a model ligand. The biotin-modified PEGylated latex was coagulated in a facile manner by the addition of avidin. From an inhibitory coagulation test using free biotin, it was found that more than 5.8 × 10 8 times of free biotin was required for the prevention of coagulation. Such a high complex formation ability of the biotin on the latex surface to avidin may be explained by the hypervalency effect. The core-shell type polystyrene latex particles, with reactive PEG brushes thus prepared, show a stable dispersity and a lowered non-specific interaction with proteinous compounds, and may have a promising potential in the diagnostic field.
Poly(styrene-co-acrolein) latex particles: Copolymerization and characteristics
Journal of Applied Polymer Science, 1990
Reactive microspheres suitable for binding proteins were prepared using emulsifier-free emulsion copolymerizations of styrene (St) and acrolein (AL) with various molar ratios of monomers St and AL. A maximum polymerization rate was obtained when the molar ratio of the monomers was 1 : 1. The diameter of the latex particles increased with increase in the amount of monomer AL. The amounts of aldehyde groups on the latex particle surfaces were determined by conductometric titration. The binding capacity of the copolymer latexes with spacer molecules was also examined.
Synthesis and Characterization of Charged Polystyrene−Acrylic Acid Latex Particles
Langmuir, 2006
Novel, monodisperse charged colloidal particles of polystyrene cross linked with divinylbenzene and surfacegrafted with acrylic acid were synthesized by emulsion polymerization and were characterized by estimating the dissociable surface charge by conductivity titration, the particle effective charge by conductivity verses particle concentration, and the particle size by dynamic light scattering and atomic force microscopy. The structural ordering and dynamics were investigated as a function of the volume fraction of the particles using static and dynamic light scattering, respectively. Furthermore, from the electrophoresis measurements, these particles are found to have a high salt tolerance due to increases in charge as a function of salt concentration.