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1

Digitale Medien

Solid state extrusion of ultra high molecular weight polyethylene. Processing and properties (1980)

Zachariades, Anagnostis E. ; Watts, Michael P. C. ; Porter, Roger S.

Stamford, Conn. [u.a.] : Wiley-Blackwell

Polymer Engineering and Science 20 (1980), S. 555-561

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ISSN: 0032-3888

Schlagwort(e): Chemistry ; Chemical Engineering

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: The techniques of solid state coextrusion and powder extrusion have been employed for the deformation of ultra high molecular weight polyethylene. Chain folded and chain extended morphologies obtained under different crystallization conditions were coextruded within a nylon 11 casing acting as a processing aid at an extrusion draw ratio (EDR) of 5 at ≤ 120°C and 0.20 GPa. The powder was compacted and extruded at ≤ 128°C and 0.23 GPa up to an EDR of 24. The physical and mechanical properties of the extrudates were evaluated and found to be dependent on intial morphology. An extrudate from the chain-folded morphology gave a low modulus of 0.71 GPa, the chain-extended morphology a modulus of 6.7 GPa, and the compacted powder a modulus of 15 GPa.

Zusätzliches Material: 7 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pen.760200808

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2

Digitale Medien

Microhardness of extruded high density polyethylene fibers (1980)

Baltá-Calleja, F. J. ; Mead, William T. ; Porter, Roger S.

Stamford, Conn. [u.a.] : Wiley-Blackwell

Polymer Engineering and Science 20 (1980), S. 393-395

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ISSN: 0032-3888

Schlagwort(e): Chemistry ; Chemical Engineering

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: High-density polyethylene of high tensile modulus has been produced by solid state extrusion using an Instron capillary rheometer. Microhardness measurements on these ultraoriented fibers have been made to assess their perfection from values of the tensile elastic modulus and shear strength. The microhardness tests were measured using a Vickers square diamond. The microhardness increased with the common temperature for crystallization and extrusion, likely due to improvement in the lateral packing of microfibrils. The variation of microhardness with draw ratio is also illustrated.

Zusätzliches Material: 5 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pen.760200603

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3

Digitale Medien

A study of the structural integrity of graphite composite structure subjected to low velocity impactPresented at the 35th Annual Technical Conference, 1980 Reinforced Plastics/Composites Institute, the Society of the Plastics Industry, Inc. (1981)

Dobyns, A. L. ; Porter, T. R.

Stamford, Conn. [u.a.] : Wiley-Blackwell

Polymer Engineering and Science 21 (1981), S. 493-498

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ISSN: 0032-3888

Schlagwort(e): Chemistry ; Chemical Engineering

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: An analysis for the transient deflections, bending strains, and interlaminar shear stresses in a simply supported laminated composite plate subject to low velocity impact has been obtained using a series solution of the plate governing equations. Results are presented showing the effect of plate geometry and impact location on damage mode. Computed stresses and strain are compared with impact test data to verify, the analysis.

Zusätzliches Material: 11 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pen.760210809

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4

Digitale Medien

Shear degradation of poly(vinyl acetate) in toluene solutions by high-speed stirring (1980)

Agarwal, S. H. ; Porter, Roger S.

New York, NY [u.a.] : Wiley-Blackwell

Journal of Applied Polymer Science 25 (1980), S. 173-185

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ISSN: 0021-8995

Schlagwort(e): Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: A poly(vinyl acetate) (PVAc) of M̄w 750,000 and M̄w/M̄n 5.10 in toluene solution was sheared in a Virtis-60 homogenizer. The polymer concentration was 3.0 to 12.0 g/100ml, and test temperature was 10 ± 0.5°C. The extent of degradation was measured by gel permeation chromatography (GPC). It was concluded that on shearing (i) the molecular weight decreases rapidly at the beginning of shearing and thereafter decreases ever more slowly toward a limiting value, (ii) the molecular weight distribution is narrowed, (iii) no degradation occurs up to 5000 rpm and thereafter increases with stirring speed, (iv) degradation is more at lower concentrations but concentration is not a sensitive variable, and (v) the chain scission occurs randomly. The Mark-Houwing relationship for PVAc in THF at 25°C was derived as [η] = 2.47 × 10-4 × M̄v0.644.

Zusätzliches Material: 11 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/app.1980.070250205

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5

Digitale Medien

Ultradrawing and crystallization of isotactic polystyrene and blends with atactic polystyrene (1981)

Wang, Li-Hui ; Porter, Roger S.

New York, NY [u.a.] : Wiley-Blackwell

Journal of Applied Polymer Science 26 (1981), S. 2373-2379

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ISSN: 0021-8995

Schlagwort(e): Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: Pure isotactic polystyrene (iPS, Mw = 8.89 × 104, Mw/Mn = 4.89) and its blends with an atactic polystyrene (aPS, Mw = 3.9 × 105, Mw/Mn 〈 1.13) were subjected to draw by solid state coextrusion at 127°C within polyethylene. The content of amorphous iPS in these blends was varied from 100 to 24.4 wt %. The extent of draw-induced crystallization was found to depend on the draw ratio and on iPS concentration. The blend with 24.4% iPS was coextruded in two stages. The highest effective draw ratio (EDR) was 7.6 and 13.7 for one- and two-stage draw, respectively. The highest crystallinity of 33.2% was obtained for pure iPS at the maximum EDR of 7.6. Considerable crystallinity was induced in blends, requiring successively higher draw ratio to reach similar crystallinity with increased aPS content. The tensile modulus increased from 1.5 to 3.2 GPa, independent of iPS concentration. Thermal shrinkage results indicate that the elastic recovery of draw in the blends is near quantitative for an EDR 〈 8. For pure iPS, extrudate elastic recovery was dramatically altered by the draw-induced crystallinity.

Zusätzliches Material: 7 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/app.1981.070260723

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6

Digitale Medien

Push-pull extrusion: A new approach for the solid-state deformation illustrated with high density polyethylene (1981)

Shimada, Toshio ; Zachariades, Anagnostis E. ; Watts, Michael P. C. ; [weitere]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Applied Polymer Science 26 (1981), S. 1309-1326

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ISSN: 0021-8995

Schlagwort(e): Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: The crystalline state deformation of high density polyethylene has been examined at an extrusion draw ratio of 30 over a range of temperatures and pressures. The experiments involve combined pushing (extrusion) and pulling through a conical die. The pressure dependence of the extrusion rate through conical dies is given by a logarithmic relation and the temperature dependence by an activation energy of ∼95 kcal/mole. An equation established for the total applied force linearly relates the pulling and extrusion pressure components and represents a force balance at the die entrance and exit. Steady-state extrusion, with or without pulling, was feasible in a pressure range beyond which fractures occurred owing to strain rate and shear or tensile failure. Under some circumstances the extrusion rate was increased by ten times. The mechanical properties and mode of deformation were not affected by pull load and fibers with a tensile modulus of 55 GPa were produced at T 〈 110°C.

Zusätzliches Material: 14 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/app.1981.070260423

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7

Digitale Medien

Ultradrawing of polystyrene by solid-state coextrusion: Shear-induced crystallization in isotactic polystyrene (1981)

Appelt, Bernd ; Porter, Roger S.

New York, NY [u.a.] : Wiley-Blackwell

Journal of Applied Polymer Science 26 (1981), S. 2841-2851

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ISSN: 0021-8995

Schlagwort(e): Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: Polystyrene with a 60% isotactic dyad content (iPS) was subjected to two-stage solid-state coextrusion at 124 and 160°C. It was shown that only shear-induced crystallization occurred with the amount of crystallinity strongly dependent on draw ratio. The steep increase in crystallinity from 0 to 29% is accompanied by a marked increase in the absolute total birefringence from 0 to 30 × 10-3 and the tensile properties, from 2.5 GPa to 4.5 GPa, giving strong evidence for the necessity of a crystalline phase to achieve higher tensile moduli. Wide-angle X-ray scattering showed a higher crystal orientation for the extrudate produced at 124°C than for the one produced at 160°C. Thermal shrinkage experiments support a partial dissipation of orientation after extrusion at 160°C and on reextrusion in general. Electron microscopy revealed a fibrous nature for the solid-state coextrudates produced at both temperatures.

Zusätzliches Material: 10 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/app.1981.070260903

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8

Digitale Medien

The modern mass spectrometer - a complete chemical laboratory (1981)

Porter, C. J. ; Beynon, J. H. ; Ast, T.

Chichester : Wiley-Blackwell

Biological Mass Spectrometry 16 (1981), S. 101-114

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ISSN: 0030-493X

Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: Using nitrobenzene as an example, various ways in which a contemporary mass spectrometer can be utilized to yield a wealth of information about the compound studied are reviewed. Applying a variety of different techniques and procedures, in addition to the conventional low resolution mass spectrum, the following nitrobenzene spectra have been obtained: collision induced dissociation mass spectrum, mass analysed ion kinetic energy spectra, collision induced dissociation mass analysed ion kinetic energy spectra, spectra obtained at constant B/E, spectra obtained at constant B2/E, high voltage scans of metastable ion fragmentation processes, consecutive fragmentations in different field free regions, charge exchange mass spectra, charge stripping mass spectra, doubly charged ion mass spectra, chemical ionization mass spectra, negative ion mass spectra, negative ion mass analysed ion kinetic energy spectra, negative ion mass analysed ion kinetic energy collision induced dissociation spectra, charge inversion spectra, etc. The complementary types of information available from the above studies are discussed to show the unique versatility of mass spectrometry as a technique for the examination of organic compounds.

Zusätzliches Material: 32 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/oms.1210160302

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9

Digitale Medien

Studies of consecutive reactions of quinones in a reversed geometry mass spectrometer (1981)

Proctor, C. J. ; Kralj, B. ; Larka, E. A. ; [weitere]

Chichester : Wiley-Blackwell

Biological Mass Spectrometry 16 (1981), S. 312-322

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ISSN: 0030-493X

Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: Consecutive reactions involving the ejection of molecules of carbon monoxide from quinone systems have been studied. Using a reversed geometry double focusing mass spectrometer, the individual steps of a consecutive reaction may be separated into different field free regions. The structure of ions formed in the ion source may be compared with those formed from the fragmentation of metastable ions in a field free region by studying differences in the pattern of translational energies released when they break. In the case of anthraquinone it is found that two structures exist for the [M—CO]+· ion. Critical energy measurements strengthen this argument. Furthermore, 18O labelling has been used to distinguish between the loss of carbon monoxide from different positions on the molecular ion of 1-hydroxyanthraquinone.

Zusätzliches Material: 3 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/oms.1210160710

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10

Digitale Medien

A novel mass marker for metastable ion scans in a double focusing mass spectrometer (1980)

Porter, C. J. ; Brenton, A. G. ; Beynon, J. H. ; [weitere]

Chichester : Wiley-Blackwell

Biological Mass Spectrometry 15 (1980), S. 564-567

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ISSN: 0030-493X

Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: Characterization and assignment of the products of metastable decompositions which are transmitted by a double focusing mass spectrometer, is often complicated by the inability to measure precisely the parent/daughter ion mass values directly from the spectra which appear on chart paper. This is often because there are considerably fewer peaks in these types of spectra compared with a normal mass spectrum obtained from high energy reactions in the ion source. Electronic circuits are described which permit accurate parent/daughter ion mass values to be obtained when the products of metastable decompositions are transmitted through the ZAB-2F double focusing mass spectrometer. Digital logic circuitry is also described which is used to mark mass values during a scan by driving either a solenoid pen drive unit for a chart recorder or a galvanometer on a multi-range ultraviolet oscillograph recorder.

Zusätzliches Material: 6 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/oms.1210151104

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