Methods of fabricating a hydrogel tube, and related systems, employ extrusion of a cross-linkable hydrogel solution from an annular outer nozzle of a nozzle assembly to form a cross-linkable hydrogel tube. The cross-linkable hydrogel tube is cured to form a cross-linked hydrogel tube. A second hydrogel solution can be coextruded via the axial inner nozzle to form an inner hydrogel filament coaxially positioned within the cross-linkable hydrogel tube. The cross-linked hydrogel tube can be functionalized with collagen to enable cell adhesion, and cells can be cultured on the luminal surfaces of these tubes to yield tubular endothelial layers. A 3D printed coaxial nozzle can be used to fabricate biofunctional tubular conduits that can be utilized for engineering in vitro models of tubular biological structures.

The instant invention provides a polyethylene blend-composition suitable for blown films, and films made therefrom. The polyethylene blend-composition suitable for blown films according to the present invention comprises the melt blending product of: (a) from 0.5 to 4 percent by weight of a low density polyethylene having a density in the range of from 0.915 to 0.935 g/cm.sup.3, and a melt index (I.sub.2) in the range of from greater than 0.8 to less than or equal to 5 g/10 minutes, and a molecular weight distribution (M.sub.w/M.sub.n) in the range of from 6 to 10; (b) 90 percent or greater by weight of a linear low density polyethylene composition has a density in the range of 0.900 to 0.935 g/cm.sup.3, a molecular weight distribution (M.sub.w/M.sub.n) in the range of 1.5 to 4.5, a melt index (I.sub.2) in the range of 0.1 to 5 g/10 minutes, a molecular weight distribution (M.sub.z/M.sub.w) in the range of less than 3, vinyl unsaturation of less than 0.1 vinyls per one thousand carbon atoms present in the backbone of said composition, and a zero shear viscosity ratio (ZSVR) in the range from 1 to less than 2; (c) optionally a hydrotalcite based neutralizing agent; (d) optionally one or more nucleating agents; (e) and optionally one or more antioxidants.

A method of making and using a stretchable film includes an extruding operation where molten plastics materials are extruded into a tube and a blowing operation in which the tube is blown to expand a diameter of the tube and form a blown-film tube. The blown-film tube is slit to form a film sheet that may be deformed elastically in a machine direction.

A single or multiple lumen catheter is disclosed which includes an expandable lumen. The expandable lumen is movable from a collapsed or sealed configuration to an open or expanded configuration. In the open configuration, the expandable lumen is dimensioned to receive a guidewire or stylet or facilitate the introduction of fluids into a patient.

The invention describes a method for monitoring a film bubble (6) in an outlet region after it emerges from an outlet die and before it leaves a calibration apparatus of a blow film line, the method comprising the following steps: detecting the wavelength of the radiation emitted from at least two different locations of the outer surface of the blown film at different points in time following one another by means of at least one optical sensor determining locations of the same wavelength determining the variation over time of the locations of the same wavelength.

An air ring comprises a circular plenum in fluid communication with a source of pressurized air. An upper and lower annular lips are in fluid communication with the plenum through upper and lower channels and are arranged to supply air to the blown film bubble. A plurality of vanes are disposed in the upper channel and extend radially inwardly from the plenum to the upper annular lip. The vanes divide the upper channel into a plurality of radially extending channel segments. Each vane has a selected length and a distal end proximal the upper annular lip, the distal end being spaced from the upper annular lip no greater than about 20% of the length of the vanes. A powered plunger extends between the vanes of each of the channel segments to vary the cross-sectional area of the channel segments.

The invention relates to an apparatus for producing tubular films stretched in-line by blow molding with an extruder, a film blowing line, a lay-flat unit, an oscillating haul-off unit, and a stretching line for monoaxially stretching the film laid flat in machine direction. According to the invention, the stretching line is arranged above the extruder between the lay-flat unit and the oscillating haul-off unit.

The invention relates to a method and arrangement of crosslinking or vulcanizing an elongate element, the method including an extrusion step in which a conductor element is coated by a layer of crosslinkable synthetic material and a crosslinking step in which crosslinking reaction is carried out after the extrusion step. The crosslinking reaction is carried out at first in a first heating zone by heating by heating the coated conductor element in a temperature of 550 degrees Celsius or higher. The first heating zone is located downstream of the extrusion step. After the first heating zone the crosslinking reaction is carried further by heating the coated conductor in a temperature of 200-300 degrees Celsius in a second heating zone.

Barrier films are prepared from a blend of two high density polyethylene blend components and a high performance organic nucleating agent. The two high density polyethylene blend components have substantially different melt indices. Large reductions in the moisture vapor transmission rate of the film are observed in the presence of the nucleating agent when the melt indices of the two blend components have a ratio of greater than 10/1. The resulting barrier films are suitable for the preparation of packaging for dry foods such as crackers and breakfast cereals.

The disclosure relates to forming shaped thermoplastic articles having smooth peripheries. Many thermoplastic articles have sharp edges formed upon molding or cutting the article from a feedstock sheet. Such sharp edges can damage thin plastic films or flesh which they contact, and smoothing the edges is desirable. Described herein are methods of forming a smooth periphery for such sharp-edged articles by rolling over the sharp edge. The smoothing operation is performed by forming a deflectable flange including a bend region separated from the potentially sharp peripheral edge by a spacer, deflecting a portion of the deflectable flange, and softening at least one bent portion of the deflectable flange to yield a smooth periphery upon cooling.