THE EFFECT OF SLNGLE AND MIXED MICELLES OF SURFACTANTS ON POLYMERIZATION OF ACRYLAMIDE

Acrylamide is conveniendy polymerized in aqueous solution lo a water soluble polymer. The measurements of kinetic parameters of polymerization of acrylamide, in aqueous and micellar solution, have been earned out by conduction calorimeter. The polymerization is initiated by sodium sulfite and sulfite-persulfate redox system. The effect of initiator and monomer concentration as well as temperature and surfactants on polymerization rale constant has been investigated. The analog thermogram method has been employed to calculate the rate constants. The activation energy is calculated from Arrhenius relationship and molecular weights are determined by viscometry. Rate equations have been derived and reaction mechanism hove been suggested. The rate of reaction is found to increase with temperature and monomer concentration.     

MHD non-Newtonian micropolar fluid flow and heat transfer in channel with stretching walls

A study is presented for magnetohydrodynamics （MHD） flow and heat transfer characteristics of a viscous incompressible electrically conducting micropolar fluid in a channel with stretching walls. The micropolar model introduced by Eringen is used to describe the working fluid. The transformed self similar ordinary differential equations together with the associated boundary conditions are solved numerically by an algorithm based on quasi-linearization and multilevel discretization. The effects of some physical parameters on the flow and heat transfer are discussed and presented through tables and graphs. The present investigations may be beneficial in the flow and thermal control of polymeric processing.     

Influence of Micellar Propinquity on Dynamics of Ce(IV)‐Catalyzed BZ Oscillatory Reaction under Stirred Conditions

Oscillating reactions often employed to mimic and understand complex dynamics in biological systems are known to be affected in aggregated host environments. The dynamic evolution of the oscillatory Belousov–Zhabotinsky (BZ) reaction upon addition of increasing amounts of anionic (sodium dodecylbenzenesulfonate; SDBS), cationic (hexadecyltrimethylammonium bromide; CTAB), nonionic (polyoxyethylene(20) cetyl ether; Brij58), and binary mixtures (CTAB + Brij58 and SDBS + Brij58) of surfactants was monitored using potentiometry at 25 and 35°C under stirred batch conditions. The experimental results reveal that the oscillatory parameters of the Ce(IV)‐catalyzed BZ reaction are significantly altered depending on the concentration and nature of restricted micellar host environments. In the presence of ionic surfactants, it is proposed that the evolution of the oscillatory BZ system may be due to atypical proficiency (related to hydrophobic and electrostatic interactions) of such organized self‐assemblies to affect the reactivity by selectively confiscating some key reacting species. However, the response of the BZ system to nonionic Brij58 was attributed to the reaction among the alcoholic functional groups of the surfactant with some vital species of the BZ reaction. Moreover, the nonionic + ionic binary surfactant systems exhibited behaviors representative of both the constitutive single surfactant systems.