Potassium persulfate, as initiator

The ionic nature of the radicals generated, by whatever technique, can contribute to the stabilisation of latex particles. Soapless emulsion polymerisations can be carried out usiag potassium persulfate as initiator (62). It is often important to control pH with buffets dutiag soapless emulsion p olymerisation. 

In this study, mechanical properties of emulsion copolymers of viityl acetate and butyl aciylate, which consisted of a nonionic emulsifier (30 mol ethoxylated nottyl-phenol), an oligomeric stabilizator, and ammonium persulfate or potassium persulfate as initiators by changing monomer ratios from 90 10 to 10 90 for VAc BuA, were determined by differential scanning calorimeter. 

Very recently, Ghosh and Mandal have reported (20) a thorough kinetic investigation of the polymerization of styrene in the two phase system water/o-dichiorobenzene using potassium persulfate as initiator and tetrabutylammoniurn bromide These studies were conducted at and pH, and found that the rate showed a square root dependence... 

In the polymerization of styrene, using potassium persulfate as initiator. Roe ( ) observed that the total number of particles in latices depended on the composition of the mixed surfactants and not on the total number of micelles. Therefore, he devaluated the micellar nucleation mechanism for emulsion polymerization as proposed by Harkins( ) -Smith-Ewart(j). 

The purpose of this paper is first to clarify the detailed characteristics of the emulsion polymerization of vinyl acetate using sodium laiiryl sulfate as emulsifier and potassium persulfate as initiator, and second to propose a new reaction model, based on our theory relating to the role of polymer particles, which enedsle vis to predict the number of polymer pcurticles produced and consequently, the progress of vinyl acetate emulsion polymerization. 

For the emulsion polymerization of vinyl acetate without seed polymer imder purified nitrogen, using sodium laiuyl sulfate as surfactant and potassium persulfate as initiator, at 50°C, with agitation at 400 rpm in a resin kettle of 500 ml capacity, the same research group made the following observations [143]. 

Polystyrene beads (PS) are employed as physical templates for macropore. The emulsifier-fiee emulsion polymerization mediod used here allows for the synthesise of nearly monodisperse latex beads of PS in the size of ca 100 nm [10], PS beads were prepared using 700 ml degassed water, 54 ml styrene monomer, 0.65 g potassium persulfate as initiator, and 20 ml divinylbenzene as cross-linking agent. PS beads were obtained at 70°C and 350 rpm, and dried under ambient condition. Aluminum fec-butoxide and stearic acid were separately dissolved in patent alcohol, sec-butyl alcohol, at room tempature, and then the two solutions were mixed. Appropriate amount of HNO3 solution was dropped into the mixture at a rate of 1 ml/min to acidify and hydrolyze the aluminum precursor. PS beads were added into aluminum hydroxide solution after stirring for 10 h. The final pH of the reactant was approximately 7. Organic templates, both stearic acid and PS bead, were easily removed from dried aluminum hyc xide by calcination. The overall synthetic procedure is as shown in Fig. 1. 

Poly(butyl methacrylate) latex nanoparticles have been synthesized by emulsion polymerization sodium dodecyl sulfate as a surfactant and potassium persulfate as initiator. Nanoparticles of various sizes could be synthesized in separate runs, with sizes of 100-300 nm. 

The emulsion polymerization reaction was accompHshed in conventional manner using potassium persulfate as initiator and sodium dodecyl sulfate as surfactant Stable composite latexes with diameters in the range of 50 to 150 nm were successfully produced, provided that the original clay suspension was stable enough. 

A more recent development is template polymerization [520 522]. When acrylic acid was polymerized in aqueous solution using potassium persulfate as initiator, the polymerization proceeded very slowly. In the presence of poly(vinylpyrrolidone) but under otherwise identical reaction conditions, the rate of polymerization increased dramatically, depending on the amount of PVP. At nearly equimolar concentrations of PVP and monomer, the rate of polymerization reaches a maximum value, because of the strong interaction between poly(vinylpyrrolidone) and acrylic acid in aqueous solution (Scheme 40) [523]. 

It is well-established that emulsion polymerization systems which contain carboxylic-acid monomers polymerize more rapidly than do similar reaction systems which do not contain acid. The results shown in Pig.1 show the effect of increasing levels of methacrylic acid upon the conversion-time curve for the surfactant-free emulsion copolymerization of styrene with small amounts of methacrylic acid using potassium persulfate as initiator. The ability of a given molar amount of a carboxylic-acid monomer to enhance the rate of polymerization increases as the acid becomes... 

Recently, a novel graft copolymer of hydrophobically modified inulin (INUTEC S PI) has been used in emulsion polymerization of styrene, methyl methacrylate, butyl acrylate and several other monomers. All lattices were prepared by emulsion polymerization using potassium persulfate as initiator. The z-average particle size was determined by photon correlation spectroscopy (PCS) and electron micrographs were also taken. 

Rana et al prepared P(2-EHA)-silicate nanocomposites by batch emulsion polymerization of 2-EHA in the presence of sorbitol, using potassium persulfate as initiator. The nanocomposites so prepared were shown to be intercalated by XRD, TEM and IR spectroscopy. However, according to the authors," the nanocomposite failed to satisfy the desired application in transdermal drug delivery. Consequently, they improved their product by preparing a P(2-EHA-cu-AA)-silieate nanocomposite. AA was chosen for its polarity and known bioadhesive properties and 2-EHA for its hydrophobicity and softness. Copolymers with different molar ratios of the monomers were prepared. Sorbitol was used as emulsifier and benzoyl peroxide as initiator therefore, the synthesis process" may be classified as suspension copolymerization. The drug cloxacillin sodium was added to the reaction mixture after 2 h of polymerization and 1 h before the reaction was terminated. The nanocomposites so prepared were shown to be intercalated by XRD and TEM. NMR and IR spectroscopy confirmed the copolymer formation and the absence of monomer impurities in the product. 

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