Fiber forming processing

Schmack et al. [126] spun PLA fibers through the reactive extrusion polymerization of L-lactide (92 wt%) and meso-lactide (8 wt%). In many potential textile technological applications (e.g., for nonwoven materials) the fiber forming process is of general importance. An effective polymer synthesis requires also an effective spinning process to reduce the still high cost of the PLA fibers compared with those of established synthetic fibers. 

FIGURE 20.15 Fiber-forming process using either a glass melt or marble feed. 

Not only is a liquid phase a key process element during the formation of nearly all inorganic fibers, but it must have a solution or melt viscosity of log 2.5 (or 316) to log 3.0 (or 1000) poise at the forming temperature. Even the viscosities of YAG or aluminate compositions which are only <1 poise above their melt temperature, must be raised to, and stabilized between, log 2.5 and 3.0 poise, before continuous amorphous glass fibers can be melt spun. This commonalty among almost all fiber forming processes further underscores the importance of the liquid phase among the other phases. 

The behavior of fiber forming inorganic melts is well understood [1-2], They are viscous or inviscid [3-4], i.e., have high or low viscosities, and fiber forming processes are either very fast (>1000 m/min,) when continuous amorphous glass fibers are desired, or slow (<0.1 m/min) when continuous single crystal fibers are desired. 

Simons also conducted experiments to determine the effect of solution viscosity, dielectric constant, conductivity, and solvent volatility on the fiber forming process. Simm et invented a process by which they modified the electrode, using an aimular elec-... 

Technical industries that produce fibers from both natural and synthetic materials make use of several classes of machinery. One class of machinery (for example, pelletizers and masticators) manipulates raw materials into a form that is readily transported and usable in the fiber-forming process. Another class of machinery (for example, injection molders and spinnerets) carries out the fiber-forming process, while still another class of machinery (for example, sizers and mercerizers) uses the raw fiber to provide a finished fiber product ready for consumers. 

A more recent development in the fiber industry is the utilization of recycling wastes as feedstock for fiber-forming processes. Synthetic materials such as nylon, polyethylene, and polyethylene terephalate (PET), which have historically been condemned to landfills, are now accepted for reprocessing through recycling programs and formed into useful fibers for many different purposes. The versatility of the materials themselves lends to the development of new industries based on their use. 

It is a term used to describe a class of fibers forming processes for which electrostatic forces are employed to control the production of the fiber. 

Centrifugal fiber forming processes date back to the 1920s when the Hager process was invented, whereby a stream of molten glass is fed onto a horizontal rotating disk, from which... 

Natural polymers can be made into hbers through dissolution of the polymer in an appropriate solvent and then extmsion of the polymer solution into a coagulation bath. As an example, cellulose can be made into viscose rayon fibers, cuprammonium rayon, cellulose acetate and triacetate fibers, lyocell, and modal fibers depending on the processes used to make the fibers. Other natural polymers such as mbber, chitosan, alginic acid, and protein can also be made into fibers in an appropriate fiber-forming process. 

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