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Initiator Type (initiator + type)

Distribution by Scientific Domains
Polymers and Materials Science75%

Selected Abstracts

Effect of initiator type and concentration on polymerization rate and molecular weight in the bimolecular nitroxide-mediated radical polymerization of styrene

ADVANCES IN POLYMER TECHNOLOGY, Issue 1 2010
Telma Regina Nogueira
Abstract To increase the polymerization rate in the bimolecular nitroxide-mediated radical polymerization (NMRP) of styrene, without using expensive non-commercial reagents, an experimental study using 2,2,6,6-tetramethyl-1-piperidinoxyl as a controller and tert-butylperoxy 2-ethylhexyl carbonate (TBEC) as the initiator was carried out. The basis for comparison was the bimolecular NMRP of styrene with dibenzoyl peroxide as initiator. It was found that faster polymerization rates and still relatively low polydispersities were possible using TBEC. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:11,19, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20170 [source]

Synthesis by a single-step swelling process and characterization of micrometer-sized polychloromethylstyrene/poly(butyl methacrylate) hemispherical composite particles of narrow size distribution

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008
Sigal Baruch-Sharon
Abstract Polychloromethylstyrene (PCMS) micrometer-sized particles of narrow size distribution were prepared by the dispersion polymerization of chloromethylstyrene in a mixture of ethanol and dimethyl sulfoxide. Micrometer-sized PCMS/poly(butyl methacrylate) hemispherical composite particles of narrow size distribution were prepared by a single-step swelling process of the uniform PCMS template particles with emulsion droplets of butyl methacrylate (BMA) containing benzoyl peroxide, followed by the polymerization of BMA at 73°C within the swollen template particles. The effects of various polymerization parameters, for example, BMA volume, initiator type and concentration, and toluene as the swelling solvent, on the properties (size and size distribution, morphology, polymerization yield, and composition) of the hemispherical composite particles were elucidated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Incorporation of a new alkenyl-based nonionic surfmer into acrylic latexes

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2004
Esteban Aramendia
Abstract The mechanisms by which a new nonionic alkenyl-based surfmer (Maxemul 5011Ô) was involved in acrylic emulsion polymerization were investigated. No proof of homopolymerization or of chain transfer to surfmer was obtained under the conditions studied. The effect of the initiator type, feeding time of the surfmer, particle size of the seed, and surfmer concentration, on kinetics and surfmer incorporation showed that the surfmer reacted mainly by copolymerization with the monomers in the outer shell of the polymer particles. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4202,4211, 2004 [source]

Microemulsion polymerization of styrene stabilized by sodium dodecyl sulfate and short-chain alcohols

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2001
Chorng-Shyan Chern
Abstract Styrene microemulsion polymerizations with different short-chain alcohols [n -CiH2i+1OH (CiOH), where i = 4, 5, or 6] as the cosurfactant were investigated. Sodium dodecyl sulfate and sodium persulfate (SPS) were used as the surfactant and initiator, respectively. The desorption of free radicals out of latex particles played an important role in the polymerization kinetics. An Arrhenius expression for the radical desorption rate coefficient was obtained from the polymerizations at temperatures of 50,70 °C. The polymerization kinetics were not very sensitive to the alkyl chain length of alcohols compared with the temperature effect. The maximal polymerization rate in decreasing order was C6OH > C4OH > C5OH. This was related to the differences in the water solubility of CiOH and the structure of the oil,water interface. The feasibility of using a water-insoluble dye to study the particle nucleation mechanisms was also evaluated. The parameters chosen for the study of the particle nucleation mechanisms include the cosurfactant type (CiOH), the SPS concentration, and the initiator type (oil-soluble 2,2,-azobisisobutyronitrile versus water-soluble SPS). © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3199,3210, 2001 [source]