Polyurethanes product distribution

Kaminsky90,92 has reported the product distribution obtained in the fluidized bed pyrolysis of different condensation polymers (polyesters, polyurethanes, polyamides, etc.). Polyester degradation led to 51% of gases, with a high proportion of CO and C02, and 40% of oil rich in benzene, toluene and naphthalene, the formation of water also being detected. On the other hand, polyurethane and polyamide decomposition led to the formation of about 40% gases and 55% oil. In both cases, the gases obtained contained certain amounts of HCN. 

Process parameters can be varied to change the MDA isomer distribution and oligomeric content of PMDA products. Generally, aniline to formaldehyde molar ratios of 2 to 5 are used. To increase the MDA content, higher ratios of aniline to formaldehyde are employed. Increasing the acid to aniline ratio also increases the 4,4 -MDA content of the diamine fraction. Historically, the polyurethane industry consumes as much of the 4,4 -MDI isomer as possible. Recently, however, there has been an increasing demand for higher 2,4 -MDI and 2,4 -PMDI products to be used as replacements for... 

Fig. 4. Schematic of a hemodialyzer. The design of a dialyzer is close to that of a sheU and tube heat exchanger. Blood enters through an inlet manifold, is distributed to a parallel bundle of fibers, and exits into a coUection manifold. Dialysate flows countercurrent in an external chamber the blood and dialysate are separated from the fibers by a polyurethane potting material. Housings are typically prepared from acrylate or polycarbonate. Production volume is...

Off-line coupling of HPLC with FD-MS has been used by several authors [118-121] for the determination of oligomers, oligomeric antioxidants (such as poly-TMDQ), ozonation and vulcanisation products. Pausch [122] reported on rubbers, cyclic polyurethane oligomers, as well as on the determination of the molecular weight distribution (up to 5300 Da) and oligomer analysis of polystyrene. Also the components of an aniline-acetone resin were deduced from FD-MS molecular weights [122]. 

Velsicol Chemical LLC, formerly Velsicol Chemical Corporation, designs, manufactures, markets and distributes high performance specialty chemicals and industrial intermediates, primarily based on benzoic acid and the organic compound cyclopentadiene. Its products include chlorendic anhydride and hexachlorocyclopentadiene (HEX). Chlorendic anhydride is corrosion resistant, fire resistant and has high UV stability, and is used in the synthesis of flame retardant polymers such as polyurethanes, unsaturated polyester and epoxy resins. HEX, a reactive intermediate used in the manufacture of agricultural pesticides in the production of flame retardants for the wire and cable industry and in the preparation of chlorendic anhydride. The company s products are produced primarily at a plant in Memphis, Tennessee Velsicol also maintains the Memphis Environmental Center (MEC), which focuses on managing legacy environmental liabilities. The firm is owned by Arsenal Capital Partners, a private equity firm. 

Nakajima-Kambe, T., Onuma, F., Akutsu, Y. Nakahara, T. (1995). Determination of the polyester polyurethane breakdown products and distribution of the polyurethane degrading enzyme of Comamonas acidovorans strain TB-35. Journal of Fermentation and Bioengineering, 83, 456-60. 

Urea linkages have been monitored during the extrusion production of a polyurethane-urea, through doping with a fluorescent aromatic diamine chain extender, whereas soluble poly(arylene etherjs, thioethers and sulfones have been synthesized which emit strongly in blue and red regions. Brownian dynamics have been used to determine the distribution of fluorescent resonance... 

These materials were reviewed as a special class of block copolymersThey are linear polyaddition products of diisocyanates containing nonrandom distributions of ionic centers. The preparations are similar to those of polyurethane elastomers that are described in Chapter 6. One example is a material prepared from a high molecular weight polyester that is free from ionic centers and that is terminated by isocyanate groups at each end. The prepolymer is coupled with AT-methyl-amino-2,2 -diethanol to form a segmented polymer ... 

When a miniemulsion polymerization initiated by Co y-rays was carried out to synthesize polystyrene particles [65], the dose rate and total dose were each found to aflect the size of the latex particles. Y-Hke branched surfactants were synthesized and used for y-ray miniemulsion polymerization at room temperature [66] moreover, 2wt% polyurethane used as a hydrophobe for the miniemulsion polymerization of styrene was suflBdent to ensure a shelf-Hfe of one year for the miniemulsion [67]. In both cases [66, 67], the particle size and distribution were preserved throughout the polymerization. The copolymerization of styrene with l-vinyl-2-pyrrolidone as a polar monomer in the presence of dodecane in the oil droplets, also led to the production of nanocapsules [68]. Subsequent H NMR spectroscopic analyses showed that graft copolymers had been obtained via radiation-induced polymerization, rather than random copolymers. Hence,... 

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