The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform
J. A. Walberer - One of the best experts on this subject based on the ideXlab platform.
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Rheology and structuring in organo-ceramic composites
Composites Part A-applied Science and Manufacturing, 2001Co-Authors: A J Mchugh, J. A. WalbererAbstract:Abstract The processing–structure–property relationships for calcium aluminate based organo-ceramic composites are reviewed. Processing behavior was measured with a torque-outfitted Banbury Mixer, structuring behavior was analyzed with electron microscopy, and mechanical properties were determined using flexural strength measurements. These results are discussed for composites composed of either a polyvinyl alcohol or phenol formaldehyde resin organic phase. The two materials have different processing behaviors, driven by different paste formation mechanisms, but are observed to have similar microstructure and mechanical properties. The rheology of model, non-calcium aluminate based composites was studied using a lubricated squeezing flow rheometer. The relaxation modulus following a step strain was measured for reactive systems that stiffened due to a crosslinking polymer phase or a polymerizing polymer phase and compared to that measured for non-reactive polydimethyl siloxane (PDMS) systems with filler fractions from 0 to 65% by volume and 65% filled PDMS of differing molecular weights. Comparison of the normalized relaxation moduli of the model reactive and non-reactive materials suggests similarities between the effect of filler amount and crosslinking amount and between the combined effects of molecular weight and filler amount and the degree of polymerization.
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Rheology and structuring in organo-ceramic composites
Composites - Part A: Applied Science and Manufacturing, 2001Co-Authors: A J Mchugh, J. A. WalbererAbstract:The processing-structure-property relationships for calcium aluminate based organo-ceramic composites are reviewed. Processing behavior was measured with a torque-outfitted Banbury Mixer, structuring behavior was analyzed with electron microscopy, and mechanical properties were determined using flexural strength measurements. These results are discussed for composites composed of either a polyvinyl alcohol or phenol formaldehyde resin organic phase. The two materials have different processing behaviors, driven by different paste formation mechanisms, but are observed to have similar microstructure and mechanical properties. The rheology of model, non-calcium aluminate based composites was studied using a lubricated squeezing flow rheometer. The relaxation modulus following a step strain was measured for reactive systems that stiffened due to a crosslinking polymer phase or a polymerizing polymer phase and compared to that measured for non-reactive polydimethyl siloxane (PDMS) systems with filler fractions from 0 to 65% by volume and 65% filled PDMS of differing molecular weights. Comparison of the normalized relaxation moduli of the model reactive and non-reactive materials suggests similarities between the effect of filler amount and crosslinking amount and between the combined effects of molecular weight and filler amount and the degree of polymerization. © 2001 Elsevier Science Ltd.
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A comparison of the rheology of reactive filled systems using lubricated squeezing flow
Journal of Rheology, 2000Co-Authors: J. A. Walberer, A J MchughAbstract:Lubricated squeezing flow rheometry has been used to study the rheological behavior of highly filled polymer composites that stiffen as they are processed. Reactive systems consisting of a crosslinking polymer phase or a polymerizing polymer phase filled with glass beads up to 65% by volume were prepared in a Banbury Mixer and compared with nonreactive systems of up to 65% filled polydimethylsiloxanes (PDMS) of differing molecular weights. The torque time profile from Banbury mixing shows a linear rise in torque with time for the crosslinking system, while the polymerizing system shows a linear followed by power law rise in torque with time. The relaxation modulus following a step strain was measured for the reactive systems at various mixing times. Comparisons of the normalized relaxation moduli of the reactive and nonreactive materials suggest similarities between the effect of filler amount and crosslinking amount and between the combined effects of molecular weight and filler amount and the degree of ...
A J Mchugh - One of the best experts on this subject based on the ideXlab platform.
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Rheology and structuring in organo-ceramic composites
Composites Part A-applied Science and Manufacturing, 2001Co-Authors: A J Mchugh, J. A. WalbererAbstract:Abstract The processing–structure–property relationships for calcium aluminate based organo-ceramic composites are reviewed. Processing behavior was measured with a torque-outfitted Banbury Mixer, structuring behavior was analyzed with electron microscopy, and mechanical properties were determined using flexural strength measurements. These results are discussed for composites composed of either a polyvinyl alcohol or phenol formaldehyde resin organic phase. The two materials have different processing behaviors, driven by different paste formation mechanisms, but are observed to have similar microstructure and mechanical properties. The rheology of model, non-calcium aluminate based composites was studied using a lubricated squeezing flow rheometer. The relaxation modulus following a step strain was measured for reactive systems that stiffened due to a crosslinking polymer phase or a polymerizing polymer phase and compared to that measured for non-reactive polydimethyl siloxane (PDMS) systems with filler fractions from 0 to 65% by volume and 65% filled PDMS of differing molecular weights. Comparison of the normalized relaxation moduli of the model reactive and non-reactive materials suggests similarities between the effect of filler amount and crosslinking amount and between the combined effects of molecular weight and filler amount and the degree of polymerization.
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Rheology and structuring in organo-ceramic composites
Composites - Part A: Applied Science and Manufacturing, 2001Co-Authors: A J Mchugh, J. A. WalbererAbstract:The processing-structure-property relationships for calcium aluminate based organo-ceramic composites are reviewed. Processing behavior was measured with a torque-outfitted Banbury Mixer, structuring behavior was analyzed with electron microscopy, and mechanical properties were determined using flexural strength measurements. These results are discussed for composites composed of either a polyvinyl alcohol or phenol formaldehyde resin organic phase. The two materials have different processing behaviors, driven by different paste formation mechanisms, but are observed to have similar microstructure and mechanical properties. The rheology of model, non-calcium aluminate based composites was studied using a lubricated squeezing flow rheometer. The relaxation modulus following a step strain was measured for reactive systems that stiffened due to a crosslinking polymer phase or a polymerizing polymer phase and compared to that measured for non-reactive polydimethyl siloxane (PDMS) systems with filler fractions from 0 to 65% by volume and 65% filled PDMS of differing molecular weights. Comparison of the normalized relaxation moduli of the model reactive and non-reactive materials suggests similarities between the effect of filler amount and crosslinking amount and between the combined effects of molecular weight and filler amount and the degree of polymerization. © 2001 Elsevier Science Ltd.
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A comparison of the rheology of reactive filled systems using lubricated squeezing flow
Journal of Rheology, 2000Co-Authors: J. A. Walberer, A J MchughAbstract:Lubricated squeezing flow rheometry has been used to study the rheological behavior of highly filled polymer composites that stiffen as they are processed. Reactive systems consisting of a crosslinking polymer phase or a polymerizing polymer phase filled with glass beads up to 65% by volume were prepared in a Banbury Mixer and compared with nonreactive systems of up to 65% filled polydimethylsiloxanes (PDMS) of differing molecular weights. The torque time profile from Banbury mixing shows a linear rise in torque with time for the crosslinking system, while the polymerizing system shows a linear followed by power law rise in torque with time. The relaxation modulus following a step strain was measured for the reactive systems at various mixing times. Comparisons of the normalized relaxation moduli of the reactive and nonreactive materials suggest similarities between the effect of filler amount and crosslinking amount and between the combined effects of molecular weight and filler amount and the degree of ...
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Evolution of mechano-chemistry and microstructure of a calcium aluminate-polymer composite: Part II. Mixing rate effects
Journal of Materials Research, 1996Co-Authors: A J Mchugh, M.a. Gülgün, W.m. KrivenAbstract:Microstructure, microchemistry and mechanical properties of hardened macro-defect-free (MDF) composites processed at various rotor rates in a Banbury Mixer were investigated. A quiescently formed calcium aluminate-polyvinyl alcohol composite served as a substitute for an unmixed system. Results from the Banbury studies in conjunction with microchemical analysis of the unmixed composite showed evidence that the polymer-particle interaction is a mechanically induced crosslinking reaction. The rate of the mechano-chemistry increases with mixing speeds. Scanning electron micrographs (SEM) and transmission electron micrographs (TEM) of hardened composites mixed for 15 min at 30, 50, 100, and 200 rpm indicate that much of the mechanical strength of MDF is due to the crosslinked interphase zones that blanket the cement grains. Stresses in the paste due to mixing can destroy the interphase layer, leading to a weaker hardened composite. Microchemical analysis revealed that the mechano-chemistry of the system did not vary with changes in the mixing conditions studied.
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Evolution of mechano-chemistry and microstructure of a calcium aluminate-polymer composite: Part I. Mixing time effects
Journal of Materials Research, 1995Co-Authors: M.a. Gülgün, W.m. Kriven, A J MchughAbstract:Paste development and evolution of microstructure, microchemistry, and mechanical properties of macro-defect-free composites were investigated. Mixing torque plots from a Banbury Mixer showed a “window of processibility” within which an optimum polymer-particle network structure formed. This processing window can be controlled by mixing rate and temperature. Network development during paste formation governed the flexural strength and microstructure of the cured material. Electron microscopy studies of the composites corresponding to various points along the mixing torque curve revealed a matrix formation-destruction process that was linked to the mixing activity and the mechano-chemistry of the system. Microchemical evolution in the composite was studied by EDS. These studies suggested that a combined convection and diffusion mechanism was responsible for the migration of Al3+ and Ca2+ ions into the different regions of the microstructure. Increasing concentrations of these elements in the polymer regions stiffened the matrix, leading to complete degradation on further mixing.
Marcoa De Paoli - One of the best experts on this subject based on the ideXlab platform.
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reactive processing of polyaniline in a Banbury Mixer
Synthetic Metals, 1999Co-Authors: Scandiucci P De Freitas, Marcoa De PaoliAbstract:Polyaniline (PAni) was doped with several concentrations of dodecylbenzenesulfonic acid (DBSA) and processed in a double screw conrotatory Banbury type Mixer coupled to a torque reomether. With the conditions studied, some samples were cured and reached a high torque. Depending on the hardening of PAni(DBSA) it was possible to make films in a roll mill. Polymer was characterized by DSC analysis were Tg transitions can be seen in the curves for thermally processed conductive PAni. Conductivity values were independent of DBSA concentrations.
Saeed M Alzahrani - One of the best experts on this subject based on the ideXlab platform.
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comparative study of internal batch Mixer such as cam Banbury and roller numerical simulation and experimental verification
Chemical Engineering Science, 2011Co-Authors: Shafaat Ahmed Salahudeen, Rabeh Elleithy, Othman Y Alothman, Saeed M AlzahraniAbstract:Abstract The mixing in non-intermeshing counter rotating internal batch Mixers using cam, Banbury and roller rotor were evaluated experimentally using thermo scientific Haake and numerical FEM simulation using the commercial CFD package Polyflow. The Carreau–Yasuda flow model was used with mesh superposition technique to generate velocity profiles and particle trajectories for HDPE. Differences in velocity profile with respect to rotor angles were examined. Distributive mixing was evaluated experimentally, as well as numerically by particle tracking analysis. Flow stretching was evaluated using the length of stretch and mixing efficiency. Since material points stayed on their streamlines near to rotor wall in the cam and Banbury Mixer, roller Mixer was found to be generally more effective and efficient, although there were still areas of poor mixing found in all.
Scandiucci P De Freitas - One of the best experts on this subject based on the ideXlab platform.
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reactive processing of polyaniline in a Banbury Mixer
Synthetic Metals, 1999Co-Authors: Scandiucci P De Freitas, Marcoa De PaoliAbstract:Polyaniline (PAni) was doped with several concentrations of dodecylbenzenesulfonic acid (DBSA) and processed in a double screw conrotatory Banbury type Mixer coupled to a torque reomether. With the conditions studied, some samples were cured and reached a high torque. Depending on the hardening of PAni(DBSA) it was possible to make films in a roll mill. Polymer was characterized by DSC analysis were Tg transitions can be seen in the curves for thermally processed conductive PAni. Conductivity values were independent of DBSA concentrations.
