Optical fibers, acrylates

Fiber(s), 77 163-188. See also Acrylic fibers Carbon fibers Filled fibers High performance fibers New fibers Olefin fibers Optical fiber(s) Polyamide fibers Regenerated cellulose fibers Vegetable fibers antimicrobial acrylic, 77 215-219... 

The entire spectrum of inorganic fibers can be divided into two classes, based on differences in the crystallinity of the solids (Ray, 1978). Synthetic fibers have been known as man-made mineral fibers (MMMF) and manmade vitreous fibers (MMVF). But fibrous materials can be approached or divided in other ways. For example, in the Concise Encyclopedia of Chemical Technology (1985) the entry for chemical fibers includes both manmade and natural polymers, with the discussion centering on carbon-based compounds such as acetates, acrylics, and cellulose. Fibers of other inorganic compounds were not mentioned in the encyclopedia under this entry, but silica glass fibers were described under the heading Optical Fibers. ... 

Improved heat-resistant UV compositions for optical fiber applications These compositions are nonurethane UV cure compositions that have neither carbamate moieties nor long-chain poly(alkylene oxide) soft segments and exhibit inherently better thermal stability measured by thermogravimetric analysis (TGA) than typical coatings for optical fibers based on urethane acrylate oligomers. 

Of a large number of possible fluorinated acrylates, the homopolymers and copolymers of fluoroalkyl acrylates and methacrylates are the most suitable for practical applications. They are used in the manufacture of plastic lightguides (optical fibers) resists water-, oil-, and dirt-repellent coatings and other advanced applications [14]. Several rather complex methods to prepare the a-fluoroalkyl monomers (e.g., a-phenyl fluoroacrylates, a-(trifluoromethyl) acrylic and its esters, esters of perfluoromethacrylic acid) exist and are discussed in some detail in [14]. Generally, a-fluoroacrylates polymerize more readily than corresponding nonfluorinated acrylates and methacrylates, mostly by free radical mechanism [15], Copolymerization of fluoroacrylates has been carried out in bulk, solution, or emulsion initiated with peroxides, azobisisobutyronitrile, or y-irradiation [16]. Fluoroalkyl methacrylates and acrylates also polymerize by anionic mechanism, but the polymerization rates are considerably slower than those of radical polymerization [17]. 

Some optical fibers or glasses have been coated with films containing acrylate-terminated polybutadiene 176,177>. 

Solution Studies. The solubility of additives within an optical fiber coating material is of prime importance since particulates can damage the surface of the glass (14) in addition to causing pinholes or tears in the coating. Solubility data for a number of commercial stabilizers are summarized in Table I. The most soluble stabilizers in the acrylate diluent are monomeric materials, particularly those with long alkyl chains. 

Figure 12. Transmission losses of four optical fibers coated with different materials as a function of winding tension on a 25-cm diameter acrylic drum. The fibers are llO-um cladding diameter, 8-um core diameter single mode fibers. These fibers have a very small core-cladding refractive index difference and transmit only the fundamental, most axially directed light ray (mode). Coating thickness is 50 um. (Reproduced with permission from Ref. 28. Copyright 1981 Gordon and Breach Science Publishers.)...

Acrylated urethanes are an Important class of commercial radiation-curable oligomers. Industrial applications of these materials cover a wide range. Including binders for magnetic media, vehicles for inks, and coatings for vinyl floor tiles, optical fibers, and paper. The compositions, and therefore, the properties of the acrylated urethanes are varied in order to meet the performance criteria of the different end uses. Properties of various acrylated urethanes will be discussed as they relate to structure. 

Chem. Descrip. Aliphatic urethane acrylate in HDDA diluent (30%) Uses Binder, resin producing tough, nonyellowing films with exc. adhesion to wide variety of substrates, very fast cure response by UV or EB, for use in screen inks, PVC floor varnishes, optical fiber coatings, adhesives... 

Chem. Descrip. Benzophenone (50%), 4-methylbenzophenone (50%) Uses Photoinitiator for systems based on acrylic oligomers and monomers, overprint varnishes, clear lacquers for wood, plastic, paper, metal, and optical fiber substrates, flooring coatings, printing inl , adhesives Features High sol. and compat. with various curable systems Properties Colorless to It. yel. clear vise, liq. faint char, odor sol. in most common org. soivs., monomers, prepolymers insol. in water Use Level 0.2-8%... 

Chem. Descrip. Trifunctional aliphatic urethane acrylate Uses Film-fomier for flexible plastic, paper, metal substrates primary oligomerfor sec. coatings in optical fibers, fiber-optic sensors, light pipes base resin for screen printing inks... 

The analysis of the diffusion-eontrolled features might be simplified by identifying the two types of free radieals the active and the trapped ones. Electron spin resonance speetroseopy shows that active (mobile) radicals give a 13-line spectrum and trapped (statie) radicals give a nine-line spectrum. Also, photopolymerization of a number of neat acrylate monomers used in polymer coatings for optical fiber was studied with photo DSC and with a cure monitor using a fluorescent probe. The acrylates had a functionality of one to six. It was found that conversion of monomers ranges from 40% to 100%. This, however, is depended upon functionality and structure of particular monomers. It can also be a function of the type and amount of the photoinitiator used. 

Wang and Cheng reported preparation of ultraviolet light-curable resin for coating optical fibers. It consists of polydimethylsiloxane epoxy acrylate and polyethylene glycol urethane acrylate. To this were added in different proportions trimethylolpropane triacrylate to modify the properties of blends. After addition of a photoinitiator the choice formulation photo cured in 5 seconds. 

Trimethylolpropane triacrylate (TMPTA) is a multifunctional acrylic monomer. It reacts with propylenei-mine to form polyfunctional aziridine. Sensitization was observed in a textile fabric printer. Patch tests were positive with the polyfunctional aziridine hardener, but were negative to TMPTA. TMPTA caused contact dermatitis in an optic-fiber manufacturing worker and was reported as a sensitizer in a floor top coat or in photopolymerizable inks. 

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