Polyacrylonitrile nanofibrous tubular structures were produced through typical and opposite charge electrospinning methods and the effect of the method as well as the two key electrospinning parameters, namely concentration of the electrospinning polymer solution and rotational speed of mandrel collector on properties of such tubular structures were studied. The smples were characterized by...

This paper discusses about preparation of biodegradable polymer /clay nanocomposites based on organically modified montmorillonite clay; i.e. cloisite 10A and biodegradable polymer chitosan by solution mixing technique and their characterization. The nanocomposites were successfully prepared and their structures were characterized by powder x-ray diffraction (XRD), particle size analyzer (Beckm...

A new microencapsulation technique that utilizes interfacial mass transfer between two mutually soluble liquids has been developed. The technique is based on formation of a solid polymer film at the interface of a solution of a water-insoluble polymer and an aqueous solution, resulting from the mutual mass transfer of solvents (i.e., solvent exchange). Reservoir-type microcapsules were prepared...

Due to the importance of nanoparticles stability in industrial applications, in this research, stability of laponite nanoparticles dispersions containing different concentrations of sodium sulfonated polyacrylamide (SPA) was investigated in electrolyte media for oil reservoirs applications. In this regard, effect of parameters such as polymer concentration, temperature, and ionic strength were ...

purification of drinking and industrial water required usage of high molecular weight polymer to cause flocculation process of dispersed suspension of contaminants. polyelectrolytes, including ionic polyacrylamide are especially appropriate for these purposes, because in this case the suspension stability can be controlled by both steric and electrostatic forces. thus the influence of solution ...

If we could realize an autonomous polymer system driven under biological conditions by a tailor-made molecular design, human beings could create unprecedented biomimetic functions and materials such as heartbeats, autonomous peristaltic pumps, etc. In order to achieve this objective, we have investigated the molecular design of such a polymer system. As a result, we were the first to demonstrat...

in recent years, great efforts have been devoted to the design of drug delivery systems. many polymeric excipients have been studied in order to make drug release fit the desired profiles. the aim of this work was to design a theophylline oral suspension, as sustained release pharmaceutical preparation in order to decrease the plasma level fluctuations and adverse effects of theophylline. micro...

Coating and encapsulation of fine particles with polymer using a supercritical antisolvent (SAS) coating process was investigated in this research. Synthesized submicron silica particles were used as host particles and poly(lactide-co-glycolide) (PLGA), a biodegradable polymer used for controlled release of drugs, was chosen as the coating material. In the SAS coating process a suspension of si...

The theoretical and practical aspects of polymer-polymer miscibility in the solid amorphous state are reviewed. The polymers include homopolymers and both random and block copolymers. Although present theoretical treatments of polymer-polymer miscibility all contain the random mixing hypothesis and are thus not applicable to mixtures that involve specific interactions between the components, mo...