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Trimethylammonium Bromide (trimethylammonium + bromide)
Selected AbstractsEffect of Counterions on Synthesis of Mesoporous Silica by the Route of TemplateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2007Yang Yu-Xiang Mesoporous silica materials with ordered hexagonal and parallel-arranged pore channel have been synthesized using cetyl trimethylammonium bromide as a template and Na2SO4 as counterions. Their ordered mesostructures were characterized by infrared spectroscopy, X-ray diffraction patterns, scanning electron microscopy, transmission electron microscopy, and nitrogen sorption analysis. The effects of Na2SO4 concentration on variations of morphology, specific surface area, and pore size were discussed; the results show that a high concentration of Na2SO4 induces the formation of crystal threads with a "tubules-within-tubule" structure, and also leads to mesoporous silica materials with spherical, fabaceous, sheet-like, or prismatic shapes. The results also show that a high concentration of Na2SO4 can make the pore size decrease, but cannot change pore wall thickness, demonstrating the stability of the hexagonal-shaped pores. [source] Evaluation and optimisation of five different extraction methods for soy DNA in chocolate and biscuits.JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2004Extraction of DNA as a first step in GMO analysis Abstract A method is described to discriminate between genetically modified (GM) and non-modified foodstuffs by detecting the presence of newly introduced genes at the protein or DNA level. Currently available methods operate almost exclusively at the DNA level and are based on the polymerase chain reaction (PCR). The first and most crucial step in this process is the isolation of DNA. In this study, five different methods for the isolation of DNA from chocolate and biscuits were evaluated, using four commercially available extraction kits and a non-commercial method for amplification of the soybean-specific lectin gene. The latter method involves the use of hot-start Taq polymerase, to prevent the formation of non-specific amplification products, and an increase in the number of cycles from 35 to 41. The performance of the non-commercial cetyl trimethylammonium bromide (CTAB)-based method was the best, taking into consideration the adaptations of the extraction procedure, although this method was more time-consuming than the others. Chocolate (white, milk and dark) and several biscuits generated positive amplification results using this PCR approach. Copyright © 2004 Society of Chemical Industry [source] Study on Superabsorbent Composite, 14MACROMOLECULAR MATERIALS & ENGINEERING, Issue 12 2006Preparation of Poly(acrylic acid)/Organo-attapulgite Composite Hydrogels, Swelling Behaviors in Aqueous Electrolyte Solution Abstract Summary: Organo-attapulgite (organo-APT) was prepared by modifying APT using four quaternary ammonium salts with various lengths of the alkyl group, including (octyl)trimethylammonium bromide (OTMABr) and (stearyl)trimethylammonium chloride (STMACl), etc. A series of composite hydrogels, poly(acrylic acid)/organo-APT, from acrylic acid (AA), and organo-APT was prepared by aqueous polymerization, using N,N, -methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator. The organification and organification degree of APT as well as the corresponding composites were characterized by FTIR, TGA, and XRD. The effects of the length of the alkyl group for different quaternary ammonium salts, organification degree of APT, and organo-APT content on water absorbency and swelling behaviors in various electrolyte solutions were investigated in this study. Equilibrium water absorbency strongly depends on chain length of the alkyl group of quaternary ammonium salts, organification degree of APT as well as organo-APT content. Longer alkyl group, higher organification degree, and proper organo-APT content are of benefit for the improvement of equilibrium water absorbency. Equilibrium water absorbency in distilled water for PAA/APT was enhanced from 350.1 to 562.1 g,·,g,1 after 10 wt.-% organo-APT, modified with STMACl for the highest degree, was introduced. The kind of cation is the key factor influencing equilibrium water absorbency of these composite hydrogels in electrolyte solutions. Organification of APT could enhance responsiveness of the corresponding composite hydrogel to electrolyte solutions. Schematic structure of PAA/organo-APT composite in a dry state (left) and in a swollen state (right). [source] Effects of hydrophilic monomer types on poly(styrene-acrylate)/montmorillonite nanocomposites made by in-site emulsion polymerization,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2009Fa-Ai Zhang Abstract Organic modified montmorillonite (OMMT) was made of pristine montmorillonite (MMT) treated with cetyl trimethylammonium bromide (CTAB). Two kinds of nanocomposites, poly(styrene-acrylate)/MMT (P(S-A)/MMT) and poly (styrene-acrylate)/OMMT (P(S-A)/OMMT) were prepared from styrene (St), hydrophilic acrylate monomer, and MMT (or OMMT) by in-site emulsion polymerization. Effects of different monomers, , -hydroxyethyl methacrylate (HEMA), acrylic acid (AA), methacryclic acid (MAA) on the thermal stability of the two nanocomposites were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The structures of the nanocomposites were characterized by infrared spectroscopy (IR) and X-ray diffraction (XRD). The morphology of the nanocomposite was observed by transmission electron microscope (TEM). The results showed that the thermal stabilities of the two composites were enhanced by the addition of HEMA, AA, or MAA. The P(S-A)/OMMT nanocomposite showed higher thermal stability than that of the P(S-A)/MMT nanocomposite. In particular, HEMA improved the thermal stability of the P(S-A)/OMMT nanocomposite, which is more efficient than methacrylic acid (MA) and AA. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||