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Reactive Surfactants (reactive + surfactant)
Selected AbstractsStability and optimum polymerized condition of polysiloxane,polyacrylate core/shell polymerADVANCES IN POLYMER TECHNOLOGY, Issue 3 2010Chengyue Ge Abstract The stable emulsion of core/shell latex with little coagulum (no more than 0.5% in quality relative to total monomers) has been prepared at low temperature with potassium-persulfate (KPS), sodium formaldehyde sulfoxylate (SFS), and 2,2,-azobis(2-(2-imidazolin-2-yl)propane)dihydrochloride (VA-044) as composite initiators by staged emulsion polymerization. Reactive surfactants were used to significantly improve the stability of emulsion. More interestingly, reverse core/shell structure was investigated when the organic silicon was added in the late period of polymerization. The effects of the emulsifier, initiators, dosage of organic silicon, and monomer's content on conversion and graft efficiency were studied in detail. Moreover, the stability of emulsion was investigated by the values of zeta potential (,) and coagulum. More importantly, the thermal performance and stability of PSI/PA composite latex was studied by the glass transition temperature (Tg). The results showed that there are appropriate values for all factors to obtain high conversion, graft efficiency, and excellent stability: The dosage of surfactant was about 0.44 g, the dosage of VA-044 was about 1000 mg kg,1, the dosage of organic silicon was about 15%, and the monomer's content was about 30%. In addition, the introduction of organic silicon improved the Tg. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:161,172, 2010; View this article online at wileyonlinelibrary. DOI 10.1002/adv.20182 [source] Morphologies and applied properties of PSI/PA composite particles synthesized at low temperaturePOLYMER COMPOSITES, Issue 11 2008Yumin Wu Latex with a poly(dimethyl-siloxane) core and a poly(methylmethacrylate- butylacrylate- 2-hydroxypropyl acrylate) shell have been prepared at low temperature with potassium-persulphate (KPS), sodium formaldehyde sulfoxylate (SFS) and 2,2,-azobis [2-(2-imidazolin- 2-yl)propane] dihydrochloride (VA-044) as composite initiators by staged emulsion polymerization. Reactive surfactants were used to significantly improve the applied properties such as water adsorption ratio and thermo-properties. Transmission electron microscopy (TEM) results indicated that increasing the amount of 2-hydroxypropyl acrylate (HPA) and butylacrylate (BA) was favorable to form the core/shell particles. Particle size distribution results showed with increasing the dosages of surfactants, initiators, and seed-latex, particle size decreased. Differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA) results indicated the high temperature-reserved of copolymer was improved in the presence of polysiloxane. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Determination of the extent of incorporation of a reactive surfactant in polystyrene latex particles via GPCJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 12 2005Zhen Lai The reactive surfactant HITENOL BC20 (polyoxyethylene alkylphenyl ether ammonium sulfate containing 20 units of ethylene oxide) was used in emulsion polymerizations of styrene with potassium persulfate as initiator. A new method to determine the amount of chemically bound surfactant was developed using GPC combined with UV detection as shown in the figure. Comparing this GPC method with the serum replacement/FTIR method reveals it to be a relatively simple and more effective means of characterization. [source] Mechanism of emulsion polymerization of styrene using a reactive surfactantJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2001X. Wang Abstract The emulsion polymerization of styrene using the reactive surfactant sodium dodecyl allyl sulfosuccinate (TREM LF-40) was studied. The polymerization kinetics were found to be unusual in that Rp was not directly proportional to Np (Rp , Np0.67). Several reasons are stated to explain the unusual kinetics, including chain transfer to TREM LF-40, copolymerization of styrene with TREM LF-40, and the influence of the homopolymer of TREM LF-40 [poly(TREM)] and/or the copolymer [poly(TREM- co -styrene)] on the entry and exit rates of free radicals. The possibility of both chain transfer and copolymerization exists primarily at the oil/water interface, whereas both can also occur in the aqueous and monomer phases. Bulk polymerizations of styrene in the presence of TREM LF-40 and poly(TREM) were conducted, and the results show that the reaction rate decreased for the styrene/TREM LF-40 system. Latex characterization by serum replacement and titration measurements provided evidence for the chemical bonding of TREM LF-40 to the polymer particles. The fraction of chemically bound reactive surfactant decreased with increasing surfactant concentration and increased with increasing initiator concentration. Relatively high contact angles of water on films cast from the latexes showed that TREM LF-40 did not migrate significantly to the surface of the film, which was consistent with the latex-surface characterization results. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3093,3105, 2001 [source] Emulsion polymerization: From fundamental mechanisms to process developmentsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2004José M. Asua Abstract Emulsion polymers are "products by process" whose main properties are determined during polymerization. In this scenario of margins reduction, increasing competition, and public sensitivity to environmental issues, the challenge is to achieve an efficient production of high-quality materials in a consistent, safe, and environmentally friendly way. This highlight reviews the investigations carried out at The University of the Basque Country to develop a knowledge-based strategy to achieve these goals. First, the research in fundamental mechanisms is discussed. This includes studies in radical entry and exit, oil-soluble initiators, propagation-rate constants of acrylic monomers, processes involved in the formation of branched and crosslinked polymers, microstructure modification by postreaction operations, the formation of particle morphology, and reactive surfactants. The advanced mathematical models developed in the group are also reviewed. In the second part, the advances in process development (optimization, online monitoring and control, monomer removal, production of high-solids, low-viscosity latices, and process intensification) are presented. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1025,1041, 2004 [source] | ||||||||||