Cetyltrimethylammonium bromide polymerization

Fig. 10.8 A where the R substituents are alkyl or heterocyclic radicals to give compounds such as cetyltrimethylammonium bromide (cetrimide), cetylpyridinium chloride and benzalkonium chloride. Inspection of the stmctures of these compounds (Fig. 10.8B) indicates the requirement for good antimicrobial activily of having a chain length in the range Cg to Cig in at least one of the R substituents. In the pyridinium compounds (Fig. 10.8C) three of the four covalent links may be satisfied by the nitrogen in a pyridine ring. Polymeric quaternary ammonium salts such as polyquatemium 1 are finding increasing use as preservatives.

The majority of the recipes described in the literature are based on the anionic sodium dodecylsulfate (SDS) as a model system. The possibility of using cationic surfactants such as octadecyl pyridinium bromide for the preparation of miniemulsions was first exploited in 1976. However, the emulsions were prepared by stirring and the resulting emulsions showed broadly distributed droplet sizes [2,39,50]. Recent work on steady-state miniemulsions showed that cationic and nonionic surfactants form well-defined miniemulsions for further miniemulsion polymerization processes, resulting in narrow size distributed stable cationic and nonionic latex particles [51]. Similar molecular amounts of the simple cationic surfactant, cetyltrimethylammonium bromide or chloride... 

Preparation and Polymerization of (0/W) Cetyltrimethylammonium Bromide Microemulsion (CTAB-yE) (5-7). An oil in water pE composed of 1.0 g of CTAB, 0.5 g of hexanol, and 1.0 g of 50% styrene-divinylbenzene in 50 mL of water was carefully prepared by slowly adding the water to a stirred mixture of the other components to yield a slightly bluish clear solution. A 0.1% solution (w/w) of initiator AIBN (based on monomer) was then solubilized in the system followed by removal of 02 (by gentle N2 bubbling for 5 min), and finally the system was heated in an oil bath (50°C) until complete polymerization was achieved as determined spectrophotometrically. Proper dilution with water was then made to give a 0.01 M CTAB-P-pE solution P-pE indicates polymerized microemulsion. 

In emulsions, amine hydrochloride constitutes the aqueous phase and acrylic ester the organic phase. Cetyltrimethylammonium bromide (CTAB) or span/twin (S/T)-type surfactants are used for emulsion polymerization. Solid dispersants such as talc and colloidal silica are often used to stabilize emulsions which are difficult to stabilize with usual surfactants. Hydrophilic colloidal silica (Aerosil 200) drastically increases the stability of some emulsions provided high amounts (up to 10%) of Aerosil are used. Random copolymers containing 10% hydroxyl groups can be used as polymeric dispersants for preparing w/o emulsions. 

Other inorganic nanoparticles have been encapsulated with miniemulsion polymerization, and a hydrophobilizing agent was used to render the particles hydrophobic prior to minianulsification. For example, calcium carbonate was pretreated with stearic acid prior to being dispersed into the monomer phase. Alumina and magnetite were pretreated with oleic acid, laponite was pretreated with a cetyltrimethylammonium bromide, and silica was pretreated with cetyltrimethyl-ammonium chloride" or methacryloxy(propyl)trimethoxysilane. ... 

The kinetic studies performed on the polymerization of MMA in the emulsion and microemulsion regions of ternary systems based on cetyltrimethylammonium bromide (CTAB) confirmed the difference in mechanisms between the two processes [84,91]. The following kinetic laws were obtained ... 

A highly porous polymeric foam can be prepared through emulsion templating by polymerizing the continuous phase of high internal phase emulsions [150], A maleimide-terminated aryl ether sulfone oligomer was copolymerized with divinylbenzene in the continuous phase, using a mixed surfactants system, cetyltrimethylammonium bromide, dodecylbenzene-sulfonic acid sodium salt, and a peroxide initiator. The polymers show a CO2 adsorption and improved mechanical properties. The materials exhibit an open cell and a secondary pore structure with surface areas of a 400 m g ... 

Scheme 1 Emulsion polymerization of methyl styrene and catalytic oxidation of poly(methyl styrene) latexes to the corresponding aldehyde and carboxylic acid groups. [AINB = a,a -azobrsisobutyromitrile, CTAB = cetyltrimethylammonium bromide, V-50 = 2,2 -azobis(2-amidinopropane) dihydrochloride]...

Long et al. ° focused on the study of MWCNT/PPy nanocomposites. First, they exfoliated as-produced MWCNTs prepared by CVD in water, using a surfactant (cetyltrimethylammonium bromide, CTAB], under sonication. The resulting mixture was then mixed with pyrrole monomer in the presence of an initiator, viz., ammonium persulfate. The in situ polymerization was finally carried out under... 

Nitrogen Mustard-1, a Chemical Warfare Agent, has been detected with a modified electrode prepared by electrochemically immobilizing, in the presence of the cationic surfactant cetyltrimethylammonium bromide, copper phthalocyanine nanorods into polypyrrole formed by the polymerization of pyrrole on gold. A linear correlation in the range 0.256 x 10 " -0.384 x 10 M was found, with a detection limit of 6.4 x 10 M [45]. 

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