M. A. J. Miah

Synthesis of γ-Alumina Particles and Surface Characterization

Alumina was synthesized via sol-gel technique by the hydrolysis of aluminium ion controlled by urea in aque- ous media. The resulting sol composed of Al(OH)3 particles coalesced and became a transparent gel. The freshly prepared gel was heated at 280°C to obtain alumina particles. The obtained particles were found to be amorphous � - alumina parti- cles with high porosity, characterized by FTIR, XRD and SBET techniques. Electron micrograph shows that the particles are nano-sized having non-spherical shape. Comparatively higher magnitude of adsorption of cationic surfactant indicated that the surface of alumina particles is negatively charged.

Carboxyl functionalized poly(methyl methacrylate-acrylic acid-ethylene glycol dimethacrylate) copolymer particles and their amination with amine-nucleophiles

Abstract Poly(methyl methacrylate-acrylic acid-ethylene glycol dimethacrylate) copolymer particles abbreviated as P(MMA-AA-EGDM) copolymer particles were prepared by soap-free emulsion copolymerization. The concentration of carboxyl group on/near the surface of particles increased with the increase in acrylic acid (AA) content in the recipe. The carboxyl groups were reacted with amine nucleophiles such ethylene diamine and 1,6-diaminohexane through preactivation with dicyclohexyl carbodiimide as a coupling agent. The modified particles were characterized by electron micrographs and FTIR spectral analysis. Adsorption behaviours of some biomolecules were measured to have idea about=-0 the polarity of the particles surface

Solvency effect of the dispersion medium on the radical polymerization of styrene in non-aqueous dispersion media

Abstract Radical dispersion polymerization of styrene in a non-aqueous media in the presence of a solvent for polystyrene was carried out to study the effect of the solvency of the continuous phase on the polymerization kinetics, the particle morphology, the size and the particle size distribution. Either ethylacetate or cyclohexanone was used as solvent in combination with ethanol as non-solvent. The polymerization kinetics is strongly influenced by the solvency of the continuous phase. The rate of polymerization is reduced in the ethanol-cyclohexanone mixture almost by a factor of two relative to the value obtained in the ethanol-ethylacetate system. On the contrary, variations in the initiator and stabilizer concentration have negligible effects on the polymerization kinetics.

Emulsion copolymerization of hydrophobic and hydrophilic monomers: an experimental study with styrene and 2- hydroxyethyl methacrylate

Abstract Ab initio emulsion copolymerization of styrene with 2-hydroxyethyl methacrylate (HEMA) at weight ratios of the hydrophilic monomer of 1 and greater was investigated at various temperatures in dependence on the concentration of sodium dodecylsulfate (SDS) and potassium peroxodisulfate as emulsifier and initiator, respectively. Both the course of the polymerization and the latex properties are strongly influenced by the hydrophilic monomer. For instance, transparent or highly translucent latexes are obtained resembling the appearance of microemulsion latexes with polymer contents as high as 10 weight-% but at much lower surfactant concentration. Moreover, polymerization rate, average particle size, and particle morphology depend on the surfactant and initiator concentration, monomer feed composition, and polymerization temperature.