Extrusion Methods

S. S. Mindlin and N. N. Samosatsky, Production of Polyethylene Products by the Extrusion Method, Goschimizdat Publishers (1959). 

Since the new carbon-carbon bond is formed intramolecularly in the sulfide extrusion method, its main potential is to be seen in cases where intermolecular condensations fail.5,6... 

Compare and contrast the bead expansion and foam extrusion methods of creating foamed polystyrene. 

THE FORMATION OF LARGE UNILAMELLAR VESICLES BY EXTRUSION METHODS... 

By analogy, benzocyclopropene (1) is formed in low yield via biradical cycliza-tion upon irradiation of benzocyclobutenone (79), upon its flash vacuum pyrolysis, or upon pyrolysis of indan-2,3-dione (80). Reaction of phthalide 81 in a RF plasma leads also to However, these latter extrusion methods are of no preparative interest. 

Also widely used in boat building, an extruded PP honeycomb, designated Nida-Core, has cost and fabricating advantages over competitive core materials. Nida-Core, developed in France and now available in the USA from Nida-Core Corporation, is produced by an extrusion method and therefore differs from most other honeycombs. Brief details are noted. 

Liu H, Pan L, Lin Q, Xu N, Lu L, Pang S, Fu S (2010) Preparation and characterization of poly (propylene carbonate)/polystyrene composite films by melt-extrusion method, e-polymers 2010 38, http //www.e-polymers.org/joumal/papers/qlin 270310.pdf. Accessed 01 April 2011... 

The sulfur extrusion method 21 has been extensively investigated for the synthesis of threo-3-methyllanthionine 25 however, in this case desulfurization was not used to generate the amino acid (either in free or protected form), but rather to form different sulfide-bridged cyclic peptides as precursors for the total synthesis of nisin (3). Development of synthetic methods in this area was particularly important in respect to the synthesis of nisin, since this lantibiotic contains four // eo-3-methyllanthionine residues. The synthesis proceeded from a protected f/zreo-3-methyl-D-cysteine in the N-terminal position and L-cysteine in the C-terminal position. 

Extrusion method to be used for thermoplastic cellulose derivatives)... 

The first step consists of making a casting powder composed of nitrocellulose, all the solid ingredients and a part of the non-explosive gelatinizer, such as carbamite (centralite), phthalates, etc. Solvent (alcohol-ether) is added to this mixture and threads of ca. 1 mm dia. are made by the usual extrusion method and cut to the length of ca. 1 mm. The solvent is removed by drying. 

Co-extrusion methods are especially desirable. Multilayer laminates formed by co-extrusion are advantageous economically and generally exhibit improvements in cohesion and adhesion relative to the various layers making up the multilayer laminate. 

Cold shaping of steel by compression reaches commercial application) 5)H.J.Pessl 8c H.H.Hautmann, Iron Age, 1953 (August), 69-73 (Factors influencing cold extrusion of steel) 6)T.Bishop, Iron Age 1953 (August), 74 7 (Tools lubricants and steels for cold extrusion) 7)J. G.Henderson 8c J.M.Bates, "Metallurgical Dictionary", Reinhold, NY (1953), 77-8 8)W.C. Tucker, Ordn 38, 458 (1953) (Examples of ammunition articles manufd at present by the cold extrusion process) 9)Battelle Memorial Institute, "Shaping of Steel by Extrusion Method", Frank-ford Arsenal, Philadelphia, Pa, 31. July, 1954... 

Another route to corrin via 4,5-seco intermediates has been established (Scheme 88).250,255 It was shown by X-ray structure analyses of the Ni-4,5-secocorrin, and its cyclization product, that the pyrrolic A and B rings are properly oriented for the reaction.250 A sulfur extrusion method was employed in the B12 synthesis of Woodward and Eschenmoser.253... 

Alternatively, the sulfur extrusion method may be useful if the a-pyrrolyl sulfide unit or its analogue (50) is more easily available than (49).275... 

Commonly accepted practice restricts the term to plastics that serve engineering purposes and can be processed and reprocessed by injection and extrusion methods. This excludes the so-called specialty plastics, eg, fluorocarbon polymers and infusible film products such as Kapton and Upilex polyimide film, and thermosets including phenolics, epoxies, urea—formaldehydes, and silicones, some of which have been termed engineering plastics by other authors (4) (see Elastomers, synthetic-fluorocarbon elastomers Fluorine compounds, organic-tetrafluoroethylene copolymers with ethylene Phenolic resins Epoxy resins Amino resins and plastics). 

Size reduction using the membrane extrusion method... 

Extrusion of sulfur dioxide from a ring-fused dihydiothiophene derivative provides an exceptionally easy method for the preparation of heterocyclic o-dimethylene compounds. These compounds are valuable intermediates in intermolecular Diels-Alder reactions. This extrusion method was used to prepare the o-dimethylene compounds 44-46 <95CC1349> as well as quinolinone derivative 47 <95TL5983>. TTie dihydrothiophene dioxide moiety also played an important role in the formation of the intramolecular Diels-Alder reaction of N-substituted pyrrole 48 <95CC807>. 

It is also possible to determine the viscosity by extrusion methods. This is analogous to the determination of viscosity with fluids, except that the material is extruded under pressure. For a fluid, the slightest pressure P will produce motion, and the volume of flow will be proportional to the pressure applied. Thus for fluids, we have the simple form of Maxwell s equation... 

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