Viscose, hollow

Hollow viscose fibers contain gas pockets produced by adding blowing agents, such as sodium carbonate, to the viscose. When carbon dioxide is released during regeneration, the fibers inflate, leading to the formation of hollow filaments. The added free volume and decrease in molecular order, increase the ability of the fibers to pick up water. 

Interest in the manufacture of different forms of rayon has resulted in the production of regular rayon, hollow viscose, spun-dyed filaments and staple rayon, crimped rayon and surface modified fibers, high tenacity rayon and high wet modulus (polynosic) rayon fibers. In chemical composition, viscose rayon and cotton are alike they are both cellulose. 

Artificial kidney Hollow viscose, hollow Remove waste products from... 

Artificial liver Hollow viscose Separate and dispose of patient s plasma and supply fresh plasma... 

The hollow viscose fibre Viloft (Lenzing, formerly Courtaulds) is marketed as The Thermal Viscose and its claimed properties are associated with its flat... 

NPB5 Single component Hollow viscose 3.3 40 100% Needlepunched (both sides)... 

Hollow viscose A rayon produced such diat there is a hoUow space inside. 

The viscosity of the 20 mg/mL PGA solution was too high to be filtered by the 2000 daltons cut-off membrane. In direct filtration or filtration experiments at the earliest stages of the enzymatic degradation, a gel appeared between the hollow fibers of the cartridge, which meant that we had to keep the reaction without filtration for 6 hours (until the viscosity of the system was adequate). 

Although the trend in the viscosity of the system tended to decrease, which facilitated filtration, a gel occasionally appeared during the filtration and a polarisation layer was always formed. The first line (1-5 h) of Figure 4 is based on an assay in which the filtration started after a reaction time of 1.5 hours, when there were still polymers and the viscosity of the system was high. A sharp decrease in the permeate flux was obtained because a gel appeared among the hollow fibers, as did a polarisation layer. The second line (4-11 h) of Figure 4 is from an assay in which the filtration started after a reaction time of 4.5 hours, when there were no polymers and the viscosity of the system was low. In this experiment no sharp decrease in the permeate flux was obtained and no gel appeared between the hollow fibers. Only the appearance of the polarisation layer was responsible for the decrease of the flux from 250 mL/h (initial flux) to almost 200 mL/h. 

For modestly viscous oils—those having viscosities of approximately 20-100 centipoise (cP)-water-soluble polymers such as polyacrylamides or xanthan gum have been used to increase the viscosity of toe water injected to displace oil from toe formation. For example, polyacrylamide was added to water used to waterflood a 24 cP oil in toe Sleepy Hollow Field in Nebraska. Polyacrylamide was also used to viscosify water used to flood a 40 cP oil in the Chateaurenard Field, France. With this process, toe polymer is dissolved in toe water, increasing its viscosity. 

The homogeneous glass, in which a few percent of alumina is added for better processing, is prepared from a melt at 1300-1500°C (Schnabel 1976) or 1000-1200°C/1450 C (McMillan 1980). It is important for the properties that the melt is as homogeneous as possible. Schnabel (1976,1978) produced glass capillaries or hollow fibers directly from the glass melt at a viscosity of 10 P. The phase separation was carried out by heat treatment between 500-800°C. 

Flow through tubes is sometimes laminar, when fluid viscosity is very high or the conduit diameter is very small, as in the case of hollow fibers. The values of h for laminar flow through tubes can be predicted by the following dimensionless equation [1, 3] ... 

Rotational Molding. Hollow articles and laige, complex shapes are made by rotational molding, usually from polyethylene powder of relatively low viscosity (57—59). The resin is in the form of a fine powder. A measured quantity is placed inside an aluminum mold and the mold is heated in an oven and rotated at low speed. The resin sinters and fuses, coating the inside of the mold. The mold is then cooled by water spray and the part solidifies, duplicating the inside of the mold. 

Thus the initial oligomer droplets should contain bubbles if hollow microspheres are to be obtained (although this is not a sufficient condition). The proportion of droplets with bubbles is increased by choosing the correct spraying conditions and resin viscosity and by introducing active centres to the original mix to promote bubble formation. 

Uekama, K., et al. 1995. Modification of rectal absorption of morphine from hollow-type suppositories with a combination of a-cyclodextrin and viscosity-enhancing polysaccharide. 

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