We develop new criteria that describe the minimum concentration limits controlling the spinnability of dilute and semi-dilute flexible polymer solutions with high molecular weight and varying polydispersity. By asserting that the finite and bounded extensional viscosity of the solution is the key material property determining the stability of a filament during spinning, we propose a new scaling...

A composite polymer surface coated on a tin oxide offers dramatic improvement in the stability and sensitivity of voltammetric measurement of pyridostigmine bromide as compared to individual tin oxide, polyaniline or polypyrrole coated electrode. A linear current response was achieved with a detection limit of 1x10 M. The stability and morphology of the polymer surfaces were determined by therm...

A new route consisting of simultaneous centrifugal spinning and solution blowing to form polymer nanofibers is reported. The fiber diameter (60-1000 nm) is shown to be a function of polymer concentration, rotational speed, and working pressure of the processing system. The fiber length is dependent on the rotational speed. The process can deliver 6 kg of fiber per hour and therefore offers mass...

We investigate the formation of polymer vesicles, or polymersomes, of polystyrene-block-poly(ethylene oxide) diblock copolymers using double emulsion droplets of controlled architecture as templates. To engineer the structure of the polymersomes, it is important to consider the concentration of diblock copolymer in the middle phase of the double emulsion. We describe how the presence of excess ...

in this article, a complete model for the mixed flow slurry reactor for polymerization of ethylene to high density polyethylene in the presence of ziegler-natta catalyst is presented. in addition to the effects of the multiple active sites, the effect of other important parameters such as the catalyst concentration, co-catalyst, hydrogen, monomer, impurities and pressure on the mass-average and...

suspension polymerization processes are significantly important in polymer bead formation. one of the important factors for bead size control in these processes is variation in surface tension. in this research, the prediction of optimum concentration of a surface active agent was investigated on the basis of the experimental surface tension diagrams. the experimental data show that the desired...

a series of ethylene-propylene-2-ethylidenebicyclo [2.2.1] hept.5-ene terpolymers (epdm) have been prepared using a vocl3/al2et3cl3 catalyst under various al/v ratios and diene concentrations via solution polymerization and characterized by ftir, mooney viscosity (ml1+4,125oc), and thermal gravimetery analyzing. the polymerization yield was seen to increase with augmentation of the al/v ratio a...

purpose of this study was to investigate the effect of the presence of the water soluble polymers viz hpmc, pvp and peg 6000 on aqueous solubility and complexation abilities of felodipine with or without presence of β-cyclodextrin (βcd) and hpβcd by phase solubility studies. the data revealed the initial increase in drug solubility followed by plateau in the presence of relatively low polymer c...

A variable optical attenuator (VOA) based on polymer stabilized twisted nematic (PSTN) liquid crystal (LC) is demonstrated. Comparing with the normal twisted nematic LC-based VOA, PSTN exhibits a much faster response time. Moreover, the polymer networks effectively eliminate the backflow effect which exists in the normal TNLC cell. The attenuation mechanism of the PSTN LC was studied. Both pola...