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1st All-American conference on rheology
Polymer Science U.S.S.R. Vol. 32, No. 5, pp. 1047-1049, 1990 Printed in Great Britain.
0032-3950/90 $10.00 + .00 © 1991 Pergamon Press plc
CHRONICLE 1st ALL-AMERICAN CONFERENCE ON RHEOLOGY*
THE 1st All-American Rheological Conference, organized by the Societies for Rheology, Mechanics, and Biorheology of North and South American countries, took place from 21 to 26 October 1989 in Montreal. The conference attracted some 500 participants--physicists, mathematicians, biologists, chemists, etc., specialized in polymer science and engineering, applied mathematics, biology, materials science, and processing of liquids, who contributed more than 250 lectures. The conference programme included multiphase systems and biopolymers, theoretical rheology and rheology of solids, and experimental rheology. The proceedings were divided into the following sections: rheological methods and instruments; experimental rheology at elevated temperature and pressure; mathematical methods and modelling of flow; rheology of biopolymers; biorheology; deformation of solids; rheology of multiphase systems; rheology of homogeneous liquids; rheology of reacting and other systems with timedependent properties; liquid crystalline polymers; adhesives, dyes, protective coatings. Two round table sessions were organized: one concerned with rheological consequences of entanglements and interactions; the other with some topical problems of applied rheology. An exhibition of new equipment and instruments for studying physico-mechanical properties of viscoelastic systems, marketed in the U.S.A. and Canada by North American and European firms, was organized during the conference. Microrheology is a branch which studies relationships between the structure of fluid systems, usually in the form of suspensions, dispersions, etc., and the macroscopic properties of the medium on the basis of a detailed description of the behaviour of structural elements involved. Diverse media fall within the scope of microrheology, including biological structured fluids (such as blood), suspensions in Newtonian and non-Newtonian liquids of particles of different size and shape (spheres, discs, cylinders, fibres, etc.), suspensions exhibiting electrical or magnetic properties, etc. The mechanism of structuring proceeding in various suspensions, induced by force fields (mechanical, electrical, electromechanical, magnetic), thixotropic destruction and reformation of structure during deformation, anisotropy of physico-mechanical properties, and mechanical degradation were analysed in lectures presented by Van de Ven (McGill University, Canada) and D. Andersen (Carnegie-Mellon University, U.S.A.), C. W. Macosko (Minnesota University, U.S.A.), K. Smith (Stanford University, U.S.A.), D. Klingenberg (Illinois University, U.S.A.), Ch. Jordan (Connecticut University, U.S.A.), and others. Chemorheology deals with physico-mechanical properties of systems containing chemically or physically entangled macromolecules. Typical problems include (i) the development of models and equations that describe the relationship between the kinetic parameters of chemical and physical processes involved in the formation of entanglements and the physico-mechanical parameters, (ii) analysis of various factors responsible for gelation, (iii) thickening of liquids by polymeric additives, (iv) investigation of viscoelastic properties of thermally reversible gels and of hydrophilic gels in the * Vysokomol. soyed. A32: No. 5, 1115-1117, 1990.
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presence of various metal ions, (v) prediction of structure, domain size, density of the network of entanglements in various gels, and of thixotropic effects in deformed systems. Considerable attention was devoted to kinetorheology, i.e. theological description and mathematical modelling of polymerization and copolymerization processes by methods of statistical physics, mathematics, and theoretical mechanics. Experimental verification of these approaches involves a complex of physico-mechanical and phy8ico-chemical methods---viscometry, the Kerr effect, magnetic rheometry (rheometry with a suspended sphere), thermogravimetry, and relaxation mechanical spectroscopy. These problems were treated in lectures by D. Brick (Princeton University, U.S.A.), E. F. Matthyss (California University, U.S.A.), L. Choplin (Lavalle University, Canada), D. G. Baird (Virginia Polytechnic University, U.S.A.), and others. Biorheology deals with physico-mechanical behaviour of biological objects in connection with various problems important for medicine. Typical tasks include the measurement of changes in structural and mechanical characteristics of biological fluids which accompany various diseases. From the point of view of theology these problems are quite new. The measurement of viscoelastic and relaxational characteristics of biological fluids opens new ways to diagnostics and prediction of the course of a number of human diseases. Several clear-cut and convincing studies can be presented as examples: the relationship between the viscosity and structure of blood and a predisposition to cardiovascular diseases, or the importance of blood fluidity for aneurism of cerebral arteries. Diagnostics of malaria based on testing the deformability of red blood cells, deformability of cells as an indicator of cytoskeletal viscosity, or modelling the energetics of skeletal muscles also belong to problems of this type. Many different specialists are attracted to this field--rheologists, physicians, biologists, physicists. Rheology of multiphase systems includes studies dealing with the physico-mechanical behaviour of complex composite materials. Several independent directions of research can be recognized: study of properties of liquid systems such as blends and filled composites, or of elastic solids. Fundamental lectures dealt with theoretical foundations of manufacture of composites, including ultra-high modulus materials; constitutive equations which relate the viscoelastic, deformational and ultimate properties, phenomenological models of non-linear deformation and the existence of the limit of fluidity. Several lectures dealt with flow of composite melts under specific conditions encountered during processing (axially symmetric extrusion, coextrusion, high-pressure moulding, etc.). A new feature was the development of more complex universal mathematical models which took into account both the internal structure of the material and the specificity of phase and strucxtural transitions during deformation and processing. Some models include terms which describe the non-linear response to deformation and/or thixotropic effects. For the first time in the history of such meetings a separate session was devoted to the relationship between physico-mechanical, deformational, and ultimate properties of solid composites. Accented problems included a description of viscoelasticity at different temperatures and of ultimate behaviour in terms of sample history, deformation-induced crystallization and other structural changes, and prediction of non-linear mechanical behaviour of polymers in the glassy state. These problems are closely connected with the prediction of properties at elevated and low temperatures of composite materials subject to complex load, such as that encountered when composites are used as construction elements, protective coatings etc. The most important results in this area were presented by D. Dealy (McGill University, Canada) and R. K. Proudhomme (Lavalle University, Canada), B. Aral (Institute of Technology, Chemistry and Chemical Engineering, U.S.A.), A. Galambose (Imperial College, U.K.), L. Utracki
Chronicle
1049
(Research Institute of Industrial Materials, Canada), L. Charin (Lewis Research Centre, NASA, U.S.A.). Considerable attention was devoted to rheometry of solutions and melts, including the theoretical and methodological basis of contemporary instruments for measuring rheophysical properties of viscous and viscoelastic materials. A series of problems important for rheometry were considered: variation in and determination of the elastic components of deformation and of the first and second normal stress difference by cone-plane viscometers; estimation of viscoelastic parameters characterizing shear deformation by methods of polarization optics; estimation of physico-mechanical properties under conditions of complex deformation; measurement of mechanical properties of weak gels; application of methods of non-linear acoustics for testing the properties of non-Newtonian liquids; ultrasound methods, etc. Several trends are apparent in the new instrument for rheological studies: full automation including robotics; rapid measurement and evaluation due to microprocessor control and use of online computers; attempts to achieve universality by providing software packages, including programs for solving typical applied tasks on the basis of different physical models; production of a series of instruments which can form a part of a line for ultra-rapid testing of properties during processing. Rheometry of polymer solutions and melts is studied seriously in a number of the largest research centres: McGill University (Department of Chemical Engineering), Brooklyn Polytechnic Institute (Department of Chemical Engineering), University of Wales, National University of Mexico, Technical High School in Zurich, Polytechnic Institute in Karlsruhe, F.R.G., and others. Yu. G. YANOVSKII
Translated by M. KUBfN
0032-3950/90 $10.00 + .00 © 1991 Pergamon Press plc
CHRONICLE 1st ALL-AMERICAN CONFERENCE ON RHEOLOGY*
THE 1st All-American Rheological Conference, organized by the Societies for Rheology, Mechanics, and Biorheology of North and South American countries, took place from 21 to 26 October 1989 in Montreal. The conference attracted some 500 participants--physicists, mathematicians, biologists, chemists, etc., specialized in polymer science and engineering, applied mathematics, biology, materials science, and processing of liquids, who contributed more than 250 lectures. The conference programme included multiphase systems and biopolymers, theoretical rheology and rheology of solids, and experimental rheology. The proceedings were divided into the following sections: rheological methods and instruments; experimental rheology at elevated temperature and pressure; mathematical methods and modelling of flow; rheology of biopolymers; biorheology; deformation of solids; rheology of multiphase systems; rheology of homogeneous liquids; rheology of reacting and other systems with timedependent properties; liquid crystalline polymers; adhesives, dyes, protective coatings. Two round table sessions were organized: one concerned with rheological consequences of entanglements and interactions; the other with some topical problems of applied rheology. An exhibition of new equipment and instruments for studying physico-mechanical properties of viscoelastic systems, marketed in the U.S.A. and Canada by North American and European firms, was organized during the conference. Microrheology is a branch which studies relationships between the structure of fluid systems, usually in the form of suspensions, dispersions, etc., and the macroscopic properties of the medium on the basis of a detailed description of the behaviour of structural elements involved. Diverse media fall within the scope of microrheology, including biological structured fluids (such as blood), suspensions in Newtonian and non-Newtonian liquids of particles of different size and shape (spheres, discs, cylinders, fibres, etc.), suspensions exhibiting electrical or magnetic properties, etc. The mechanism of structuring proceeding in various suspensions, induced by force fields (mechanical, electrical, electromechanical, magnetic), thixotropic destruction and reformation of structure during deformation, anisotropy of physico-mechanical properties, and mechanical degradation were analysed in lectures presented by Van de Ven (McGill University, Canada) and D. Andersen (Carnegie-Mellon University, U.S.A.), C. W. Macosko (Minnesota University, U.S.A.), K. Smith (Stanford University, U.S.A.), D. Klingenberg (Illinois University, U.S.A.), Ch. Jordan (Connecticut University, U.S.A.), and others. Chemorheology deals with physico-mechanical properties of systems containing chemically or physically entangled macromolecules. Typical problems include (i) the development of models and equations that describe the relationship between the kinetic parameters of chemical and physical processes involved in the formation of entanglements and the physico-mechanical parameters, (ii) analysis of various factors responsible for gelation, (iii) thickening of liquids by polymeric additives, (iv) investigation of viscoelastic properties of thermally reversible gels and of hydrophilic gels in the * Vysokomol. soyed. A32: No. 5, 1115-1117, 1990.
1047
1048
Chronicle
presence of various metal ions, (v) prediction of structure, domain size, density of the network of entanglements in various gels, and of thixotropic effects in deformed systems. Considerable attention was devoted to kinetorheology, i.e. theological description and mathematical modelling of polymerization and copolymerization processes by methods of statistical physics, mathematics, and theoretical mechanics. Experimental verification of these approaches involves a complex of physico-mechanical and phy8ico-chemical methods---viscometry, the Kerr effect, magnetic rheometry (rheometry with a suspended sphere), thermogravimetry, and relaxation mechanical spectroscopy. These problems were treated in lectures by D. Brick (Princeton University, U.S.A.), E. F. Matthyss (California University, U.S.A.), L. Choplin (Lavalle University, Canada), D. G. Baird (Virginia Polytechnic University, U.S.A.), and others. Biorheology deals with physico-mechanical behaviour of biological objects in connection with various problems important for medicine. Typical tasks include the measurement of changes in structural and mechanical characteristics of biological fluids which accompany various diseases. From the point of view of theology these problems are quite new. The measurement of viscoelastic and relaxational characteristics of biological fluids opens new ways to diagnostics and prediction of the course of a number of human diseases. Several clear-cut and convincing studies can be presented as examples: the relationship between the viscosity and structure of blood and a predisposition to cardiovascular diseases, or the importance of blood fluidity for aneurism of cerebral arteries. Diagnostics of malaria based on testing the deformability of red blood cells, deformability of cells as an indicator of cytoskeletal viscosity, or modelling the energetics of skeletal muscles also belong to problems of this type. Many different specialists are attracted to this field--rheologists, physicians, biologists, physicists. Rheology of multiphase systems includes studies dealing with the physico-mechanical behaviour of complex composite materials. Several independent directions of research can be recognized: study of properties of liquid systems such as blends and filled composites, or of elastic solids. Fundamental lectures dealt with theoretical foundations of manufacture of composites, including ultra-high modulus materials; constitutive equations which relate the viscoelastic, deformational and ultimate properties, phenomenological models of non-linear deformation and the existence of the limit of fluidity. Several lectures dealt with flow of composite melts under specific conditions encountered during processing (axially symmetric extrusion, coextrusion, high-pressure moulding, etc.). A new feature was the development of more complex universal mathematical models which took into account both the internal structure of the material and the specificity of phase and strucxtural transitions during deformation and processing. Some models include terms which describe the non-linear response to deformation and/or thixotropic effects. For the first time in the history of such meetings a separate session was devoted to the relationship between physico-mechanical, deformational, and ultimate properties of solid composites. Accented problems included a description of viscoelasticity at different temperatures and of ultimate behaviour in terms of sample history, deformation-induced crystallization and other structural changes, and prediction of non-linear mechanical behaviour of polymers in the glassy state. These problems are closely connected with the prediction of properties at elevated and low temperatures of composite materials subject to complex load, such as that encountered when composites are used as construction elements, protective coatings etc. The most important results in this area were presented by D. Dealy (McGill University, Canada) and R. K. Proudhomme (Lavalle University, Canada), B. Aral (Institute of Technology, Chemistry and Chemical Engineering, U.S.A.), A. Galambose (Imperial College, U.K.), L. Utracki
Chronicle
1049
(Research Institute of Industrial Materials, Canada), L. Charin (Lewis Research Centre, NASA, U.S.A.). Considerable attention was devoted to rheometry of solutions and melts, including the theoretical and methodological basis of contemporary instruments for measuring rheophysical properties of viscous and viscoelastic materials. A series of problems important for rheometry were considered: variation in and determination of the elastic components of deformation and of the first and second normal stress difference by cone-plane viscometers; estimation of viscoelastic parameters characterizing shear deformation by methods of polarization optics; estimation of physico-mechanical properties under conditions of complex deformation; measurement of mechanical properties of weak gels; application of methods of non-linear acoustics for testing the properties of non-Newtonian liquids; ultrasound methods, etc. Several trends are apparent in the new instrument for rheological studies: full automation including robotics; rapid measurement and evaluation due to microprocessor control and use of online computers; attempts to achieve universality by providing software packages, including programs for solving typical applied tasks on the basis of different physical models; production of a series of instruments which can form a part of a line for ultra-rapid testing of properties during processing. Rheometry of polymer solutions and melts is studied seriously in a number of the largest research centres: McGill University (Department of Chemical Engineering), Brooklyn Polytechnic Institute (Department of Chemical Engineering), University of Wales, National University of Mexico, Technical High School in Zurich, Polytechnic Institute in Karlsruhe, F.R.G., and others. Yu. G. YANOVSKII
Translated by M. KUBfN