High-rate production

N.G. Glumac, Y.J. Chen, G. Skandan, B. Kear, Scalable high-rate production of non-agglomerated nanopowders in low pressure flames . Materials Letters, 34, 148-153, (1998). 

The last example of application of smart materials to PPE described in this chapter deals with shock absorbers. With shear thickening fluids, complete flexibility is maintained in static conditions while the material instantaneously hardens upon impact at high rate. Products based on elastomer foam and 2D and 3D impregnated fabrics are already on the market, with a particular target at sports, defense, and law enforcement applications. 

The high heat-up rates allow for rapid cure of parts and a consequential highly flexible manufacturing route through high-rate production principles. This would allow composites manufacturers to move away from a... 

Five to ten years ago, these materials were still in the incubation period of development. Since that time, polymer research and system commercialization have progressed significantly. Desired weight benefits provided the primary impetus for producing cost-effective raw materials and developing qualified processes to ensure eventual production development. That development is now under way on flight-critical composite components in high-rate production. 

A., Zelioli, A., Barborini, E., Ducati, C., and Milan , P. (2012) High-rate production of functional nanostructured films and devices by coupling flame spray pyrolysis with supersonic expansion. 

High-Rate Production of High-Purity, Nonagglomerated Oxide Nanopowders in Flames... 

Although many variations of the cyclohexane oxidation step have been developed or evaluated, technology for conversion of the intermediate ketone—alcohol mixture to adipic acid is fundamentally the same as originally developed by Du Pont in the early 1940s (98,99). This step is accomplished by oxidation with 40—60% nitric acid in the presence of copper and vanadium catalysts. The reaction proceeds at high rate, and is quite exothermic. Yield of adipic acid is 92—96%, the major by-products being the shorter chain dicarboxytic acids, glutaric and succinic acids,and CO2. Nitric acid is reduced to a combination of NO2, NO, N2O, and N2. Since essentially all commercial adipic acid production arises from nitric acid oxidation, the trace impurities patterns ate similar in the products of most manufacturers. 

Eastman Chemical has utilized a unique, high temperature solution process for propylene polymerization. Polymerization temperatures are maintained above 150°C to prevent precipitation of the isotactic polypropylene product in the hydrocarbon solvent. At these temperatures, the high rate of polymerization decreases rapidly, requiring low residence times (127). Stereoregularity is also adversely affected by high temperatures. Consequentiy, the... 

In contrast to triphenylphosphine-modified rhodium catalysis, a high aldehyde product isomer ratio via cobalt-catalyzed hydroformylation requires high CO partial pressures, eg, 9 MPa (1305 psi) and 110°C. Under such conditions alkyl isomerization is almost completely suppressed, and the 4.4 1 isomer ratio reflects the precursor mixture which contains principally the kinetically favored -butyryl to isobutyryl cobalt tetracarbonyl. At lower CO partial pressures, eg, 0.25 MPa (36.25 psi) and 110°C, the rate of isomerization of the -butyryl cobalt intermediate is competitive with butyryl reductive elimination to aldehyde. The product n/iso ratio of 1.6 1 obtained under these conditions reflects the equihbrium isomer ratio of the precursor butyryl cobalt tetracarbonyls (11). 

A further improvement in platinum catalysis is claimed from use of tin(Il) haUde and phosphine ligands which are rigid bidentates, eg, l,2-bis(diphenylphosphinomethyl)cyclobutane (27). High rates for a product containing 99% linear aldehyde have been obtained. However, a pressure of 10 MPa (1450 psi) H2 CO is requited. 

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