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  • 1
    Electronic Resource
    Electronic Resource
    The concept of solid solvent as a processing aid (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 2739-2751 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The concept of solid solvent entails the use of low-molecular weight crystalline materials (LMC) as a processing aid. A LMC as an ideal solid solvent mixed into a polymer is expected to become a solvent for the polymer at high processing temperatures, reducing the melt viscosity and thus enhancing the processability, but to become a nonsolvent for the polymer at low use temperatures precipitating out of the polymer without adversely affecting the properties of the polymer. The feasibility of such a concept was examined using acetanilide as a potential solid solvent for polystyrene (PS) and two ABA-type block copolymers containing PS end blocks. Acetanilide demonstrated the essential features required of a solid solvent supporting the concept of solid solvent. It had a high solubility in PS at high temperatures very effectively reducing the melt viscosity of PS and the block copolymers, and it precipitated out of PS at low temperatures although it had an undesirably high residual solubility. The concept of solid solvent appears to be a viable one.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070310828
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  • 2
    Electronic Resource
    Electronic Resource
    Screw horsepower dependence on screw speed and size - theory and experiment (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 28-37 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Within a normal operating range of extruders, it has been well established that the output increases nearly proportionally to the screw speed but the screw horsepower increases more than proportionally to the screw speed, making the screw HP difficult to predict. It has been also known in scale-up of extruders that the output may be predicted with reasonable accuracy but the screw HP is difficult to predict. No sound theoretical or empirical method predicting screw HP in a scale-up calculation has been offered heretofore. Since a screw performs solid conveying, melting and pumping (or metering) functions simultaneously, any theoretical analysis of screw HP has to consider all three extrusion theories; solid conveying theory, melting theory and pumping theory. In this paper, semi-theoretical equations for predicting screw HP as a function of screw speed and size are developed. Experiments are conducted to test the utility of these equations and the implications of the experimental results on extrusion theories are discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140106
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  • 3
    Electronic Resource
    Electronic Resource
    Melting behavior of solid polymers on a metal surface at processing conditions (1978)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 18 (1978), S. 711-720 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The melting or plasticating behavior of seven commercial polymers (high density polyethylene, low density polyethylene, polypropylene, polyoxymethylene copolymer, polystyrene, poly(methyl methacrylate), and polycarbonate (PC) was investigated using an experimental apparatus specifically designed to measure the melting rate and the viscous shear stress of a solid polymer on a steel surface under precisely controlled conditions of temperature, velocity, pressure and sample width comparable to actual processing. The melting rate (per unit polymer solid/metal contact area) was found to increase with increasing temperature for all polymers except PC, to decrease with increasing sample width and to increase less than proportionally to velocity. Pressure increased the melting rate somewhat for most of the polymers. The viscous shear stress decreased with increasing temperature for all polymers except PC, decreased with increasing sample width and increased with increasing velocity. Pressure generally increased the viscous shear stress. PC showed an unusual behavior with a maximum in the melting rate near 4200°F(215.5°C) and also a maximum in the viscous shear stress near 445°F (229.4°C). The present melting model could be examined unequivocally for the first time using our experimental results. Comparison of our experimental results with the predictions of the present melting model clearly indicates the inadequacy of the present melting model, Our experimental results will provide a basis for rational development of a reliable melting model.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760180906
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of lubricants on the second fusion behavior of rigid polyvinyl chloride (1979)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 19 (1979), S. 1110-1116 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Rigid polyvinyl chloride (RPVC) is thermally unstable and difficult to process. The processibility of RPVC compounds markedly depends on the type and level of lubricants present. Lubricants are compounded into RPVC powder and the resulting dry blend is either directly converted into the final product requiring the resin to fuse only once, or pelletized first followed by conversion into the final product in a subsequent operation requiring the resin to fuse twice. The effects of lubricants on the first fusion have been well studied but little is known about the second fusion. We studied the effects of eleven common lubricants on the second fusion of a RPVC master, batch at three levels of concentration at several temperatures., The lubricants were compunded with the RPVC powder, the dry blends molded into one-inch cube samples, and the molded samples fused under shearing conditions comparable to the actual processing. We found that the effects of the lubricants on the second fusion were generally the same as those on the first fusion. Apparently, the properties of the lubricants and their interactions with the RPVC resin are not altered by the first fusion history.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760191508
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  • 5
    Electronic Resource
    Electronic Resource
    Friction and its effect on the mechanical- to-thermal energy conversion during extrusion of poly(vinylidene chloride) (1993)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 1261-1269 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Solid state friction reduction has been found to be an effective method for extrusion stabilization of a high coefficient of friction (COF) thermally sensitive polymer. A poly(vinylidenechloride) copolymer (PVDC) was studied alone and blended with various polyolefins to change its frictional behavior. COF of the polymer rubbing on a metal surface was measured under conditions typical of an extrusion process. These results correlated well with the measured mechanical energy consumed during extrusion. Of the polyolefins studied, high and low density polyethylene were found to be very effective for lowering friction and improving extrusion performance of the PVDC. Polypropylene was found to be much less effective. Interface temperature where melting occurs due to frictionally generated heat has been experimentally shown to be a function of COF and the bulk metal temperature.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760331906
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  • 6
    Electronic Resource
    Electronic Resource
    On the scale-up of plasticating extruder screws (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 626-632 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In the most commonly used scale-up method of plasticating extruder screws, the screw channel depth is increased by the square root of the diameter ratio while the screw RPM is decreased by the square root of the diameter ratio such that the output rate increases proportionally to the square of the diameter ratio. This scale-up method, largely based on the pumping function of the screw, often leads to a higher melt temperature, a higher screw horsepower consumption per unit output rate and an inferior melt quality from the larger diameter screw. Analysis of the common scale-up method reveals that, although the shear rate in the melt is kept constant, the average residence time and the peripheral screw speed are increased for the larger diameter screw. Our recent study on the melting mechanism also reveals that the melting capacity increases less than the pumping capacity. A detailed examination of the common scale-up method in this paper shows that the pumping capacity and the solid conveying capacity increase more than necessary while the melting capacity increases insufficiently.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240904
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  • 7
    Electronic Resource
    Electronic Resource
    Plasticating single-screw extrusion theoryPresented before the 28th Annual Technical Conference of the Society of Plastics Engineers, New York, N. Y., May, 1970. (1971)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 11 (1971), S. 93-98 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Various solid conveying, melting, and metering theories developed for plasticating screw extrusions are reviewed. Some recommendations for improving the present melting theories are presented. It is pointed out that the overall performance of a screw extruder can be predicted only by combining the solid-conveying, melting and metering theories into a complete mathematical package because the three functions of a screw extruder depend on each other and cannot be separated. A suggestion is made on how to combine these three theories.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760110204
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  • 8
    Electronic Resource
    Electronic Resource
    Maximum pressure developed by solid conveying force in screw extruders (1975)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 15 (1975), S. 29-34 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: There are two distinct solid conveying theories that can be applied to plasticating screw extruders. One is Darnell and Mol's theory based on a solid-to-solid friction model and the other is Chung's theory based on a viscous shearing model. The two theories predict very different solid conveying performances for a same set of conditions. In this paper, the maximum pressures that can be developed inside plasticating screw extruders by the solid conveying force are calculated using each of the two theories. Comparison of the results may shed some light on the applicability of each theory for a particular extrusion operation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760150105
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  • 9
    Electronic Resource
    Electronic Resource
    Compressibility of polyethylene melts at low pressures (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 1277-1281 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Branched polyethylene has quite different rheological and physical properties from its linear homologue. Despite their many different properties, the densities of linear and branched polyethylene melts at atmospheric pressure have been reported to be identical at all temperatures. However, it was not known whether their melt densities at a given temperature would also be identical at all pressures. In this investigation, the compressibilities of one linear and two branched polyethylene melts at 160°C, 190°C, and 220°C were studied, and it was found that they had an identical compressibility over the present experimental pressure range of ca. 0-455 psi (0-31 atm). Both the specific volume and the density at each temperature could be very accurately expressed as linear functions of pressure for this pressure range. Time-dependent compressive property was not observed within the present low pressure range.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150521
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  • 10
    Electronic Resource
    Electronic Resource
    Newtonian behavior of a styrene-butadiene-styrene block copolymer (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 1149-1156 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The melt rheological behavior of an anionically polymerized styrene-butadiene-styrene (SBS) block copolymer sample (S: 7 × 103 and B: 43 × 103) was studied using a Weissenberg rheogoniometer. Highly non-Newtonian behavior, high viscosity and high elasticity, which are characteristics of ABA type block copolymers, were observed at 125°C, 140°C, and 150°C. The data at these temperatures superimposed well onto a master curve giving a constant flow activation energy. However, the data at 175°C indicated a marked change in the flow mechanism between 150°C and 175°C. At 175°C, the sample showed Newtonian behavior, negligible elasticity, and deviation from the master curve. These findings may be considered as an indication that the SBS block copolymer sample undergoes a structural change from a multiphase structure at low temperatures into a homogeneous structure at some temperature between 150°C and 175°C.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140616
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