Polymeric fibers

Propene is used as a starting material for numerous other compounds. Chief among these are isopropyl alcohol, acrylonitrile, and propylene oxide. Isopropyl alcohol results from the hydration of propylene during cracking and is the primary chemical derived from propylene. Isopropyl alcohol is used as a solvent, antifreeze, and as rubbing alcohol, but its major use is for the production of acetone. Acrylonitrile is used primarily as a monomer in the production of acrylic fibers. Polymerized acrylonitrile fibers are produced under the trade names such as Orion (DuPont) and Acrilan (Monsanto). Acrylonitrile is also a reactant in the synthesis of dyes, pharmaceuticals, synthetic rubber, and resins. Acrylonitrile production occurs primarily through ammoxidation of propylene CH3- CH = CH2 + NH3 + 1.5 02—> CH2 = CH - C = N + 3 H20. 

III (10-DAB) was carried out from which baccatin III was produced in an enzyme reactor. The enzyme reactor comprised a hollow-fiber polymeric ultrafiltration membrane, with immobilized acetyl transferase from Taxus species. The process enabled the production of baccatin III without requiring complicated purification steps of the acetyl transferase. The purification of the baccatin III is also made distinctly easier [20]. 

Figure 8.7. Shell-and-tube membrane module containing either hollow-fiber polymeric membranes or tubular inorganic membranes.

Dardenne, D.S. Woodtruder (Patents Pending) system for extrusion of wood fiber polymeric composites. In Wood-Plastic Conference, Conference Proceedings, Baltimore, MD, December 5-6, 2000 187-188. 

The most common polymer supports used for chiral catalyst immobilization are polystyrene-based crosslinked polymers, although poly(ethylene glycol) (PEG) represents an alternative choice of support. In fact, soluble PEG-supported catalysts show relatively high reactivities (in certain asymmetric reactions) [le] which can on occasion be used in aqueous media [le]. Methacrylates, polyethylene fibers, polymeric monoliths and polynorbornenes have been also utilized as efficient polymer supports for the heterogenization of a variety of homogeneous asymmetric catalysts. 

Table 3.2 Hollow-fiber polymeric membranes typically used as supports for SLM...

The critical transmembrane pressure calculated using this equation is valid for cylindrical pores. Usually, the commercial hoUow-fiber polymeric... 

Acrylics and Modacrylics Polybenzimidazole and Carbon Fibers Polymerization Process Technology Fiber Formation... 

In general terms a man-made fiber polymerization scheme can be classified as either a batch or a continuous process. In a pure batch process the polymerization step is carried out separately from fiber formation in reactors that receive discrete charges of monomer(s). In a continuous polymerization (CP), monomer is fed continually into the reactors, and polymer is continually removed downstream. For some polyamides and polyesters, fiber formation may or may not be an integral part of the CP line. Most modern polymerization schemes are continuous processes, and these are slowly replacing much of the older batch technology. 

U.S. Pat, Nos. 6,122,877 [107] and 6,682,814 [108] (both by Andersen Corporation) disclose a cellulosic fiber-polymeric composite comprising 45-70% of thermoplastic polymers such as PVC, polyethylene and its copolymers, polystyrene, polyacrylate, polyester and their mixtures, and 30-65% of wood fiber, such as sawdust. 

U.S. Pat. No. 6,780,359 [109] (by Crane Plastics Company, TimbeiTech) discloses a cellulosic fiber-polymeric composite comprising mixing a cellulosic material, such as wood fiber, with a plastic material, such as HDPE, LDPE, PVC, chlorinated PVC, polypropylene, EVA, ABS, and polystyrene, to form a cellulosic reinforced plastic composite. 

AI3-16415 EINECS 216-341-5 Geropon MLS/A Methallyl sulfonate Methallylsulfonic acid, sodium salt 2-Methyl-2-propene-1-sulfbnic acid, sodium salt NSC 2253 2-Propene-1-sulfonic acid, 2-methyl-, sodium salt Sodium 2-methyl-2-propenesulfonate Sodium 2-methylprop-2-ene-1-sulphonate. Dye improver reactive comonomer for acrylic fibers polymerization reacbve emulsifier or coemulsifier in latex emulsion polymerization. Rhdne-Poulenc. 

MAJOR USES Used in the production of fungicides, pharmaceuticals, cortisone, leather, gelatin, cosmetics and pH electrodes strengthens animal fibers polymerization inhibitor. 

M. Marcolongo, P. Ducheyne, J. Garino, E. Schepers, Bioactive glass fiber/polymeric composites bond to bone tissue, J. Biomed. Mater. Res. 39 (1998) 161-170. 

Funabashi, M. and Kunioka, M. (2005) Biodegradable composites of poly(lactic acid) with cellulose fibers polymerized by aluminum triflate. Macromolecular Symposia, 224,309-321. 

Synonyms 2-Methyl-2-propene-1-sulfonic acid sodium salt Empiricai C4H7NaO S Formuia H2C=C(CH3)CH2S03Na Properties M.w. 158.15 m.p. > 300 C anionic Uses Dye improver reactive comonomer for acrylic fibers polymerization dyeable polyacrylonitrile/polyvinyl acetate comonomer reactive emulsifier or coemulsifier Manuf./Distrib. Aldrich http //www.sigma-aidrich.com, Monomer-Polymer Dajac Labs Trade Name Synonyms Geropon MLS/A [Rhodia HPCII http //www.rhodia-hpcii.com]... 

Lignocellulosic fiber/polymeric matrix 4 (mm) IFSS (MPa) Reference... 

In this paper, the salient features of the fracture process in different types of fibers, polymeric, metallic, and ceramic are described. Points of commonality and difference are highlighted. 

The manufacturing process is similar to that of other synthetic fibers polymerization, extrusion, drawing. The polymer is melted in a liqnid and extmded at a... 

Molecular sieve membranes An ultrafine microporous membrane is formed from a dense, hollow-fiber polymeric membrane by carbonizing or from a glass hollow fiber by chemical leaching. Pores in the range 0.5-2 nm are claimed 45-48... 

The earliest report on CMS membranes obtained from hollow fiber polymeric membranes appears to be from Koresh and Soffer (1983) and Soffer et al. (1987). By comparing CMS membranes derived from different polymeric membranes, Jones and Koros (1994a) found that the ones from aromatic polyimides yielded the best separation and mechanical properties. The polymers tested by Jones and Koros were cellulose acetate, polyaramides, and polyimides. Polyfurfural alcohol was used by Foley and co-workers (Foley, 1995 Shiflett and Foley, 1999 Strano and Foley, 2002). A comparison of the O2 permeances and O2/N2 selectivities showed that the CMS membrane from polyimide was indeed much better than that from polyfurfural alcohol, as will be seen shortly. 

Drawbacks of the CMS membranes from hollow-fiber polymeric membranes have also been reported (Jones and Koros, 1994b Jones and Koros, 1995). These membranes were vulnerable to organic vapors as well as moisture. These molecules seemed to adsorb strongly in the pores and reduced the fluxes of the permanent gas molecules. Membrane deterioration was observed with organic contaminations at concentrations as low as 0.1 ppm. However, a promising regeneration process was reported by the use of propylene significant recovery of the... 

Carbon fiber reinforced carbon Carbon fiber polymeric matrix materials (polysulfone, poly(aryl) ether ketone Carbon fiber reinforced bone cement A-W glass-ceramic... 

Lesser reductions were observed in quasi-isotropic laminates (Rriz and Stinchcomb 1982) and no diminutions occurred in the longitudinal properties of carbon fiber composites. Smaller reductions in transverse strength were also noted in several graphite and glass fiber polymeric composites immersed in sea water (Grant 1991). 

In summary, unreinforced polymers will have a creep modulus in tension that is less than the creep modulus in compression or a creep compliance in tension that is larger than the creep compliance in compression. For continuous fiber polymeric composites, the situation is reversed. 

Upon homopolymerization of the Y MPS, it loses the functional C = C groups that can copolymerize with the matrix. Formation of chemical bonds between the silane and the matrix resin is not possible at normal conditions when homopolymerization of the silane is complete. It has been observed that the major part of the C = C groups of y-MFS on E-glass fibers polymerize in air at room temperature in one month without the matrix resin. Nevertheless, the glass fiber/y-MPS system that has been stored in air for many months produces an FRP similar to freshly treated glass fibers. Small concentrations of the residual C = C bonds of the Y MPS adds further strength to reinforcement by chemical bonds. 

---