Spinning apparatus

Poly[5-(alkylamino)borazines] 7-10 exhibited suitable viscoelastic and thermal stabilities to be extruded in the molten state through the monohole spinneret of a lab-scale melt-spinning apparatus. Thus, an extruded filament (diameter, 200 gm) was drawn with a windup unit, that is, a graphite spool. This provided green fibers with a wide range of diameters (16 =s (f> =s 50 gm Table 2), depending on polymer architecture. 

The first spinning experiments were performed with dissolved raw silk of the silkworm Bombyx mori [31] and the golden orb-weaver Nephila clavipes [32]. For this purpose a minimized wet-spinning apparatus was constructed [31]. The apparatus was capable of spinning fibers from solutions containing 10 mg of soluble protein. 

Figure 2. Schematic of the component parts of the spinning apparatus (side view) and their relationship to each other (see text) (131...

Figure 4. Plot of spinning rates (kHz) vs. applied gas pressures (in pressure per square inch) for a 10 mm version of the spinning apparatus. Curve A sample with nitrogen gas with the apparatus in an open environment in air. Curve B spun with helium gas with the apparatus in an open environment in the air. Curve C spun with helium in a closed glass tube (11 mm l.D.) as in the probe arrangement. The sample was spun in an atmosphere of helium in this case. The three arrangements gave stable spinning over the range of pressures indicated in the figure and were followed for both solid and hollow rotors and for samples spun at different...

Fibers emerging from the spinneret are cooled under controlled conditions, passing over guides and rollers to a take-up spool or bobbin. Often a finish is applied before windup to control static electricity and friction (Stevens 1993). Large-scale production machinery produces fiber at a rate of thousands of feet a minute. A schematic diagram of a melt-spinning apparatus is drawn in Figure 8-10. 

Fiber Formation. Solutions were extruded from a wet spinning apparatus (Bradford Univ. Research Ltd., equipped with a six hole spinneret, hole diameter 0.23 mm) by wet or air-gap spinning. Methanol was the coagulant. Alternatively, fibers were extruded from a syringe into methanol through a 2.5 cm air-gap. 

Coagulation bath Fig. 6. Schematic diagrams of the wet spinning apparatus. 

An important hardware addition in the development of fiber-spinning protocols is the availability of customized wet-spinning apparatus from Nakamura Services Co. in Japan (Figure 7.9). 

FIGURE 7.9 The customized wet-spinning apparatus at the Intelligent Polymer Research Institute, University of Wollongong. 

C. A. Fyfe, H. Mossbruger, and C. S. Yannoni, "A simple magic-angle spinning apparatus for routine use in NMR spectroscopy of solids," J. Magn. Resonance 36, 61-68 (1979). 

Chemagnetics, Inc., 208 Commerce Dr., Ft. Collins, CO 80524. (including magic angle spinning apparatus)... 

A vertical spinning apparatus was developed by Tomonari et al. in 1951 [110]. The density of the spinning solution was lower than that of the coagulating bath. Figure 4.16 shows that both the solutions flow inside a spinning tube smoothly and parallel to one another. 

FIGURE 4.16 Schematic of vertical wet-spinning apparatus for PVA with sodium sulfate coagulation bath. 

A technique commonly used to prepare amorphous alloys is melt spinning, developed originally by Bedell (1975). This method produces thin amorphous ribbons with a thickness of 10-40 jam. A melt-spinning apparatus is shown schematically in fig. la. The melt is contained in a quartz or alumina vessel (A) which... 

The melt-water vapor equilibrium is shifted because the spinning apparatus is very dry. The polycondensation equilibrium is thus displaced toward higher degrees of polymerization. 

Liivak, O., Blye, A., Shah, N., Jehnski, L.W., 1998. A microfabricated wet-spinning apparatus to spin fibers of silk proteins. Structure—property correlations. Macromolecules 31 (9), 2947-2951. 

Plasma desorption mass spectrometer Biolon 20 and aluminized polyester targets are from Biolon. The spin apparatus was homemade (description available from the author). Gilson adjustable automat pipettes (2, 10, 20, 100, and 2(X) 1) are from Gilson Medical Electronics. The Heto Vac VRl vacuum centrifuge equipped with a Heto CTllO cold trap is from Heto Lab). 

A conventional spinning apparatus is shown in Figure 3 (63). Polymer chips are melted in a larger extmder, which, in turn, feeds a manifold spinning line. 

Fig. 3. Conventional melt spinning apparatus. Reproduced with permission from Ref 66. Copyright 1966 Noyes Publications.

Figure 10.4. Scheme of basic electrostatic spinning apparatus 64]... 

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