Inverse microemulsion copolymerization of styrene and acrylic acid

In this paper we report the first account on the copolymerization of a water-soluble monomer (acrylic acid) and a water-insoluble monomer (styrene) in ionic inverse microemulsions. Three different surfactants were used: AOT, a cationic surfactant, DDAB (didodecyldimethylammonium bromide) and a mixture of two cationic surfactants, DDAB and DTAB (dodecyltrimethylammonium bromide). The polymerization was carried out at 60 °C using either a water-soluble (K2S2O8) or an oil-soluble (azobisisobutyronitrile or AIBN) initiator. Copolymerization of acrylic acid and styrene was achieved with the three surfactants only when AIBN was used. With potassium persulfate, only polyacrylic acid was produced

Inverse microemulsion copolymerization of styrene and acrylic acid

In this paper we report the first account on the copolymerization of a water-soluble monomer (acrylic acid) and a water-insoluble monomer (styrene) in ionic inverse microemulsions. Three different surfactants were used: AOT, a cationic surfactant, DDAB (didodecyldimethylammonium bromide) and a mixture of two cationic surfactants, DDAB and DTAB (dodecyltrimethylammonium bromide). The polymerization was carried out at 60 �C using either a water-soluble (K2S2O8) or an oil-soluble (azobisisobutyronitrile or AIBN) initiator. Copolymerization of acrylic acid and styrene was achieved with the three surfactants only when AIBN was used. With potassium persulfate, only polyacrylic acid was produced

Microarray data analysis: From hypotheses to conclusions using gene expression data

We review several commonly used methods for the design and analysis of microarray data. To begin with, some experimental design issues are addressed. Several approaches for pre‐processing the data (filtering and normalization) before the statistical analysis stage are then discussed. A common first step in this type of analysis is gene selection based on statistical testing. Two approaches, permutation and model‐based methods are explained and we emphasize the need to correct for multiple testing. Moreover, powerful approaches based on gene sets are mentioned. Clustering of either genes or samples is frequently performed when analyzing microarray data. We summarize the basics of both supervised and unsupervised clustering (classification). The latter may be of use for creating diagnostic arrays, for example. Construction of biological networks, such as pathways, is a statistically challenging but complex task that is a relatively new development and hence mentioned only briefly. We finish with some remarks on literature and software. The emphasis in this paper is on the philosophy behind several statistical issues and on a critical interpretation of microarray related analysis method

Electron and light microscopy studies on the domain structures of Zn 3B7O13Cl, Zn3B7O 13Br and Zn3B7O13I ferroic boracites

Poly(styrene-co-sodium acrylate) has been synthesized by emulsion polymerization of styrene and sodium acrylate at a ratio of 9:1 with the water-soluble initiator potassium persulfate. The reaction is fast, conversions are high, and the evolution of particle size follows the conversion curve. The final latex is stable and contains spherical particles 70 nm in diameter. The presence of the copolymer is confirmed by several methods including FTIR, and the copolymer evolves from rich in sodium acrylate to rich in styrene as the reaction proceeds. " 1993 Springer-Verlag.",,,,,,"10.1007/BF00296851",,,"http://hdl.handle.net/20.500.12104/41219","http://www.scopus.com/inward/record.url?eid=2-s2.0-0001123646&partnerID=40&md5=3def5991a6590b5c5368988837197fc2",,,,,,"2",,"Polymer Bulletin",,"20

Emulsion copolymerization of styrene and sodium acrylate

Poly(styrene-co-sodium acrylate) has been synthesized by emulsion polymerization of styrene and sodium acrylate at a ratio of 9:1 with the water-soluble initiator potassium persulfate. The reaction is fast, conversions are high, and the evolution of particle size follows the conversion curve. The final latex is stable and contains spherical particles 70 nm in diameter. The presence of the copolymer is confirmed by several methods including FTIR, and the copolymer evolves from rich in sodium acrylate to rich in styrene as the reaction proceeds. © 1993 Springer-Verlag

Microemulsion copolymerization of styrene and acrylic acid

The copolymerization of acrylic acid and styrene in a cationic microemulsion made with dodecyltrimethylammonium bromide is reported. Conversion of 60% and fast reaction rates are achieved. The resulting latex is a monodisperse dispersion of spherical particles of 21 nm in radius. The copolymer backbone consists of isolated acrylic acid units randomly distributed among polystyrene blocks. � 1990

Diversity of the 5? ?-globin haplotype of four ?-thalassemia mutations in the Mexican population

The location and distribution of acrylic acid and styrene in emulsions made with a cationic surfactant, cetyltrimethylammonium bromide (CTAB), or an anionic surfactant, sodium dodecylsulfate (SDS), were determined with ultra-violet spectroscopy, conductivity, and potentiometry. In these systems, the acrylic acid remains in the aqueous phase near the micelle surface, whereas the styrene is located in the micelles or in emulsified droplets. In the absence of acrylic acid, some of the styrene is solubilized in the micelle interior and some is adsorbed at the micelle inner surface. Upon addition of acrylic acid, all the styrene is displaced to the center of the micelles. The interaction between acrylic acid and CTAB micelles is stronger than that between acrylic acid and SDS micelles. With CTAB, acrylic acid is adsorbed at the micelle surface, whereas with SDS, acrylic acid remains in the intermicellar solution. These differences can account for the differences reported in the emulsion copolymerization of acrylic acid and styrene using CTAB or SDS. " 1990 Steinkopff.",,,,,,"10.1007/BF01411110",,,"http://hdl.handle.net/20.500.12104/40754","http://www.scopus.com/inward/record.url?eid=2-s2.0-0025477501&partnerID=40&md5=ed0126ed538a66dd48f84c1df4038ad0",,,,,,"8",,"Colloid & Polymer Science",,"77

Rheology of cetyltrimethylammonium tosilate-water system. 1. Relation to phase behavior

Dynamic and steady-shear rheological measurements of the AOT/water lamellar liquid crystalline phase are reported as a function of surfactant concentration. Dynamical measurements indicate that the AOT/water lamellar phase behaves as a weak gel; i.e., both the elastic and the loss moduli, G? and G? are nearly independent of frequency (?) and G? is an order of magnitude greater than G? in the range 10-2 to 102 s-1. Complex and dynamic viscosities decrease with frequency as ?-1. Steady shear measurements demonstrate a shear thinning behavior with ? ? ?-1 but ? does not tend to a Newtonian plateau at low shear rates. The measured material functions (G?, ?*, and ?) go through a minimum at around 50 wt% AOT. This minimum is explained in terms of attractive and repulsive colloidal forces in the bilayers and in terms of interactions among the liquid crystalline microdomains. " 1993 Academic Press. All rights reserved.",,,,,,"10.1006/jcis.1993.1368",,,"http://hdl.handle.net/20.500.12104/44269","http://www.scopus.com/inward/record.url?eid=2-s2.0-43949175443&partnerID=40&md5=302fad27e58b9ff5e066af7ab993a8d6",,,,,,"1",,"Journal of Colloid And Interface Science",,"6

Effective interaction parameter between topologically distinct polymers

The magnitude of the thermodynamic interaction in a bulk binary homopolymer blend due to regular branching alone has been estimated from small angle neutron scattering (SANS) measurements for the first time using blends of star and linear poly(styrene)s of well defined structure. The value of χ for a blend of deuterated four arm star (M=100 000 g/mol) with hydrogenous linear polystyrene (M=132 000 g/mol) of comparable molecular weight is χ=0.1278/T−0.0002 over the temperature range of 120–225°C for a segment volume of 100 cm3/mol. The contribution to χ ascribable to architecture effects is just distinguishable from that due to isotopic substitution alone and in surprisingly good agreement with an approximate prediction from a mean field theory. The precise value of χ varies depending on which component is labeled