Film fiber

Slit-Film Fiber. A substantial volume of olefin fiber is produced by slit-film or film-to-fiber technology (29). For producing filaments with high linear density, above 0.7 tex (6.6 den), the production economics ate more favorable than monofilament spinning (29). The fibers are used primarily for carpet backing and rope or cordage appHcations. The processes used to make slit-film fibers are versatile and economical. 

The equipment for the slit-film fiber process is shown in Figure 15 (29). An olefin film is cast, and as in melt spinning, the morphology and composition of the film determine the processing characteristics. Fibers may be produced by cutting or slitting the film, or by chemomechanical fibrillation. 

The film is fibrillated mechanically by mbbing or bmshing. Immiscible polymers, such as polyethylene or polystyrene (PS), may be added to polypropylene to promote fibrillation. Many common fiber-texturing techniques such as stuffer-box, false-twist, or knife-edge treatments improve the textile characteristics of slit-film fibers. 

Polyimides (PI) were among the eadiest candidates in the field of thermally stable polymers. In addition to high temperature property retention, these materials also exhibit chemical resistance and relative ease of synthesis and use. This has led to numerous innovations in the chemistry of synthesis and cure mechanisms, stmcture variations, and ultimately products and appHcations. Polyimides (qv) are available as films, fibers, enamels or varnishes, adhesives, matrix resins for composites, and mol ding powders. They are used in numerous commercial and military aircraft as stmctural composites, eg, over a ton of polyimide film is presently used on the NASA shuttle orbiter. Work continues on these materials, including the more recent electronic apphcations. 

A viscous solution of poly(amic acid) can be processed into films, fibers, and coatings, and the final product undergoes thermal cyclo dehydration. 

Orientation. Most articles made of HDPE, including film, fiber, pipes, and injection-molded articles, exhibit some degree of molecular and crystal orientation (21). In some cases, orientation develops spontaneously for example, during melt flow into a mold and its subsequent crystallisation. When blown HDPE film and fiber are manufactured, orientation can be introduced dehberately by stretching. 

Core technical competencies may be composed of a number of core or key technologies. The competencies in turn can support product families, platforms, or core products, which then support individual products. These products may ultimately be found in a number of forms or shapes. For example, a key technology such as polymer characterization may support a competency in polymer synthesis and architecture, which in turn supports the platform of fluoropolymers and the product family of Teflon (DuPont) fluoropolymer resins that can be found as films, fibers, or in other forms. 

The sol—gel process can be utilized to yield products within a wide range of appHcations. Some of these appHcations include production of nanocomposites, films, fibers, porous and dense monoliths, and biomaterials. 

The rapid development of many processible conducting polymers that can now be obtained as films, fibers, and molded shapes, suggests that they will be quite useful in a number of appHcations. One of the concerns presendy being addressed is the stabiUty of the conductive polymers during these specific uses. 

Polyphenylenetriazoles Thermally stable to 400-500°C (752-932°F) make film, fiber, coatings. 

Cellulose acetate (CA) has been known, and industrially employed for decades as films, fibers, filters, membranes, tubes, and utensils, as well as other consumer products, including eyewear, fashion accessories, pens, brushes, toys, among others [13]. The market for Filter Tow, which is made from crimped, endless CA filaments, has seen a tremendous growth in the cigarette market, reaching more than 600 thousand metric tons in 2003 [14]. Additionally, cellulose mono-acetates have several potential applications, because they can be made into either water absorbent, or water-soluble polymers [15]. 

SOL-GELTECHNOLOGY FOR THIN FILMS, FIBERS, PREFORMS, ELECTRONICS AND SPECIALTY SHAPES edited by Lisa C. Klein... 

For the continuous process, strips of commercial film and split-film fibers were used as described in the experiments reported. 

Various materials can be produced by sol-gel methods monoliths, thin films, fibers, powders can. Controlling of the physical and chemical parameters of production process yields materials with precisely tailored parameters such as mechanical strength, transparency, size and distribution of the pores network7. The sol-gel derived materials may provide excellent matrices for a variety of organic and inorganic compounds. 

When classifying chemical products, Seider et al. [3] identify three categories (1) basic chemicals (commodity and specialty chemicals, bio-materials, and polymeric materials) (2) industrial chemicals (films, fibers, paper,. ..) and (3) configured consumer products (dialysis devices, post-it notes, transparencies, drug delivery patches,. ..). In the manufacture of epitaxial silicon wafers, a thin film of crystalline silicon is often deposited on a polished crystalline silicon... 

The modification of PET with low levels of naphthalate comonomer increases the Tg and enables optimally oriented articles (films, fibers, containers, etc.) to resist higher temperatures without shrinkage. Heat setting under tension may be applied to further extend thermal stability. In addition, when retention of optical transparency is required, such copolymers crystallize less readily than PET, and may readily be quenched from the melt to the transparent, amorphous state. Thus,... 

Ethylene glycol, CH2OHCH2OH, looks like ethane with hydroxyl groups (-OH) on each carbon in place of a hydrogen. EG is used as the essential ingredient in antifreeze and in the production of PET and polyester film, fiber, and plastics. 

Polymers have been valued since antiquity for their solid state properties. By this is meant their ability to undergo chain entanglement or co-linear orientation and microcrystalll-zatlon in the solid state. This underlies their use as structural materials, films, fibers, and elastomers. Such properties still constitute the driving force for most pol)nner-orlented research, especially with respect to the synthesis of heat-stable, radiation-stable, or highly flexible materials. 

IR spectroscopy is not only useful for determining the chemical constitution of polymers. It additionally provides profound information on chain orientation and on the orientation of attached lateral substituents of polymers. In this case, polarized IR radiation is applied which is only absorbed by an IR-active bond if the plane in which the electrical field vector E of the IR beam oscillates is parallel to the transition dipole moment p of the vibration to be excited. If, on the other hand, the transition dipole moment p is perpendicular to the electrical field vector E of the IR beam no absorption is observed. Using this effect, the degree of orientation of a polymer sample (film, fiber) can be estimated by comparing the intensity at maximum /(11) and at minimum I ) absorption, i.e., the dichroic ratio. 

For analytical purposes and an initial characterization, quick tests (duration minutes to few hours) are sufficient. However, the estimation of the usefulness as an industrial material needs long-term testing (months to years) in different environments (air, water, solvents, etc). The numerous other tests employed in engineering practice to determine mechanical (and other) properties, as well as the special methods for testing rubbers, films, fibers, foams, coatings, and adhesives, will not be dealt with here. 

Film, fiber, coatings Dynamic modulus Flexure... 

Radiation-induced grafting in its simplest form involves heferogeneous sysfems, with the substrate being film, fiber, or even powder and fhe monomer fo be graffed onto fhe subsfrafe a neaf liquid, vapor, or solufion. 4i Currently, three main radiation grafting techniques are known ... 

Diffuse-reflectance MIRS has found a number of applications for dealing with hard-to-handle solid samples, such as polymer films, fibers, or solid dosage forms. Reflectance MIR spectra are not identical to the corresponding absorption spectra, but sufficiently close in general appearance to provide the same level of information. Reflectance spectra can be used for both qualitative and quantitative analysis. Basically, reflection of radiation may be of four types specular, diffuse, internal, and attenuated total. 

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