No abstract

Speed of sound, u, of dodecyltrimethylammonium bromide (DTAB) aqueous solutions has been determined at 295.15, 302.15 and 309.15 K. The speeds of sound, u, data have been used to estimate isentropic compressibility, K s , apparent molal isentropic compressibility, φ k(s), acoustic impedance, Z, molal sound of speed, R m , and relative association, R A , of DTAB in aqueous solution. These parameters have been interpreted in terms of solute-solute and solute-solvent interactions and micellar behavior of DTAB.

In this investigation micron-sized monodisperse magnetic composite polymer particles with amino and amide functional groups were prepared considering their applications in biotechnology. First, polystyrene/poly (acrylic acid-acrylam- ide-N-N-methylene-bis-acrylamide) [PS/P(AA-AAm-MBAAm)] composite polymer particles were prepared by seeded copolymerization. The carboxyl groups present on or near the particles surface were modified by amine-nucleophile, ethylene diamine (EDA), through pre-activation with dicyclohexyl carbodiimide as coupling agent. The aminated particles were then magnetically modified and named as aminated-Fe3O4 composite particles. Formation of such magnetic composite particles was confirmed by scanning electron micrographs, FTIR-spectra and magnetic susceptibility measurement. The produced composite particles were paramagnetic. To see the relative hydrophilic character of the particles surface the adsorption behavior of trypsin (TR) as biomolecule was studied on PS particles and aminated-Fe3O4 composite particles. The magnitude of adsorbed TR on PS particles was higher than that on aminated-Fe3O4 composite particles

This paper covers the targetable magnetic iron oxide core and biodegradable, cost-effective, eco-friendly polymer shell considering their versatile and extensive use in various fields. In this work, poly (acrylic acid-co-2hydroxyethylmethacrylate) [P (AA-co-HEMA)] magnetic composite polymer particles were synthesized by the method of twostage solution polymerization in aqueous media. At first synthesis, the Fe 3 O 4 particles by a traditional co-precipitation method and in the second stage occurs the formation of the polymer using acrylic acid (AA) as monomer and 2-hydroxyethyl methacrylate (HEMA) as co-monomer. Finally, the synthesized iron oxide particles encapsulated by a polymer to modify the surface of composite particles. The modified composite particles were then characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometry (XRD), Dynamic Light Scattering (DLS), Thermo Gravimetric Analysis (TGA) and Vibrating Sample Magnetometry (VSM). The existence of carboxyl (-COOH) & hydroxyl (-OH) groups in the composite particles was confirmed by FTIR. XRD indicated the crystalline cubic spinel structure of magnetic composite particles. VSM results showed that the synthesized coated composite particles were paramagnetic in nature magnetic saturation is obtained 72.72 emu/g and 97.9 emu/g for bare Fe 3 O 4 and coated magnetic composite particles respectively.