L. A. Utracki

Commercial polymer blends

Preamble. Abbreviations in Appendices. Part One: Polymer Science and Technology. 1. Introduction. 2. Polymer Industry. 3. Development of Polymer Processing. 4. Development of Polymer Science. 5. Nomenclature of Polymeric Systems. Part Two: Technical and Economic Rationality for Polymer Blending. 6. Reasons for, benefits and problems of blending. 7. Morphology. 8. Rheology. 9. Development of Polymer Blends. Part Three: Commodity Resin Blends. 10. Styrenics: Polystyrene and Styrene Copolymers. 11. Polyvinylchloride. 12. Polyvinylidene Halide Blends. 13. Poly(methy)methacrylate, PMA and PMMA, Blends. 14. Polyethylene Blends. 15. Polypropylene. Part Four: Engineering Resin Blends. 16. Polyamide Blends. 17. Polyester Blends. 18. Polycarbonate Blends.19. Polyoxymethylene (Acetal Resins). 20. Polyphenleneether. 21. Specialty Resin Blends. 22. Recycling and Biodegradable Blends. References. Appendices: I. List of international abbreviations for polymers. II. List of the commercial blends. III. The major types of polymer blends. IV. Polymer blends discoveries and developments. Index.

Interfacial tension coefficient from the retraction of ellipsoidal drops

Keywords: interfacial tension ; polymer blends ; ellipsoid retraction Reference LTC-ARTICLE-1997-011 URL: http://www3.interscience.wiley.com/cgi-bin/jhome/36698 Record created on 2006-06-26, modified on 2016-08-08

Influence of shear and elongation on drop deformation in convergent–divergent flows

Abstract The effects of shear and elongation on drop deformation are examined through numerical simulation and experiment. A two-dimensional formulation within the scope of the boundary element method (BEM) is proposed for a drop moving under the influence of an ambient flow inside a channel of a general shape, with emphasis on a convergent–divergent channel. Both the drop and the suspending fluid can be either Newtonian or viscoelastic of the Maxwell type. The predicted planar deformation is found to provide accurate description of the physical reality. For example, small drops, flowing on the axis, elongate in the convergent part of the channel, then regain their circular form in the divergent part, confirming the experimental observations. Drops placed off-axis are found to rotate during the flow. These drops thus have longer residence time as well as larger and irreversible deformation than those moving on the axis. Both theory and experiment show a difference in deformability for Newtonian and viscoelastic drops in a slit flow. Initially, a Newtonian drop is reluctant to deform, but then deformation is rapid. A viscoelastic drop initially deforms readily, but then the deformation slows down. The slit flow does not flatten drops whose diameter is at least 10 times smaller than the slit gap. The effects of shear and elongation stress, the viscosity ratio, the drop diameter-to-channel-gap ratio, the initial drop position, the interfacial tension, and elasticity of the dispersed and ambient phases were examined using the BEM.

Free volume and viscosity of polymer‐compressed gas mixtures during extrusion foaming

Extrusion foaming of molten polystyrene (PS) with three physical foaming agents (PFAs), carbon dioxide (CO 2 ), 1,1,1,2-tetrafluoroethane, and 1-chloro-1,1-difluoroethane, is considered. The concentration of injected PFA was W = 0-5 wt % for CO 2 and W = 0-15 wt % for the other agents. The aim of this work is to connect flow and equation of state (EOS) properties under the temperature and pressure conditions encountered during extrusion foaming. The constant-stress viscosity η at σ 12 ≅ 40 kPa was measured online at temperatures T ≅ 110-210 °C and pressures P ≅ 5-13 MPa. The EOSs of PS and PFA are analyzed in terms of the Simha-Somcynsky lattice-hole theory. The hole fraction, h = h(T,P), is extracted from the analysis of the experimental pressure-volume-temperature data, and a conventional free-volume fraction is also obtained and related to h. Next, these functions are related to the constant-stress viscosity of PS/PFA mixtures in terms of alternative mixture rules. The T, P and composition dependencies of the system viscosity can be satisfactorily expressed in terms of volume-average hole fractions of the two constituents. An analysis of Newtonian viscosities of PS/PFA systems measured by Kwag et al. [Kwag, C., Manke, C. W., and Gulari, E., J Polym Sci Part B: Polym Phys, 1999, 37, 2771] under steady-state conditions results in a satisfactory agreement with the developed procedure.

Polymer physics : from suspensions to nanocomposites and beyond

Contributors. Preface. Robert Simha: A Life with Polymers (Ivan G. Oterness and Alexander M. Jamieson). PART I Rheology. 1 Newtonian Viscosity of Dilute, Semidilute and Concentrated Polymer Solutions (Alexander M. Jamieson and Robert Simha). 2 Polymer and Surfactant Drag Reduction in Turbulent Flows (Jacques L. Zakin and Wu Ge). 3 Nanorheology of Polymer Nanoalloys and Nanocomposites (Ken Nakajima amd Toshio Nishi). 4 Volume Relaxation and the Lattice-Hole Model (Richard E. Robertson and Robert Simha). 5 Dynamics of Materials at the Nanoscale: Small-Molecule Liquids and Polymer Films (Gregory B. McKenna). PART II Thermodynamics. 6 Equations of State and Free-Volume Content (Pierre Moulinie and Leszek A. Utracki). 7 Spatial Configuration and Thermodynamic Characteristics of Main-Chain Liquid Crystals (Akihiro Abe and Hidemine Furuya). 8 Bulk and Surface Properties of Random Copolymers in View of Simha-Somcynsky Equation of State (Hans-Werner Kammer and Jorg Kressler). 9 Physical Aging (John (Iain) M. G. Cowie and V. Arrighi). PART III: Position Annihilation Lifetime Spectroscopy. 10 Morphology of Free-Volume Holes in Amorphous Polymers by Means of Positron Annihilation Lifetime Spectroscopy (Giovanni Consolati and Fiorenza Quasso). 11 Local Free-Volume Distribution from PALS and Dynamics of Polymers (Gunter Dlubek). 12 Positron Annihilation Lifetime Studies of Free Volume in Heterogeneous Polymer Systems (Alexander M. Jamieson, Brian G. Olson, Sergei Nazarenko). PART IV Physics of the Polymeric Nanocomposites. 13 Structure-Property Relationships of Nanocomposites (Cyril Sender, Jean Fabien Capsal, Antoine Lonjon, Alain Bernes, Philippe Demont, Eric Dantras, Valerie Samouillan, Jany Dandurand, Colette Lacabanne and Lydia Laffont). 14 Free Volume in Molten and Glassy Polymers and Nanocomposites (Leszek A. Utracki). 15 Metal Particles Confined in Polymeric Matrices (Luigi Nicolais and Gianfranco Carotenuto). 16 Rheology of Polymers with Nano-Fillers (Leszek A. Utracki, Maryam M. Sepehr, and Pierre J. Carreau). Appendix A: Nomenclature and Symbols. Appendix B: Robert Simha Publications. Subject Index.

Boundary-element analysis of planar drop deformation in confined flow. Part 1. Newtonian fluids

Abstract A boundary element formulation is presented for the general two-dimensional simulation of confined two-phase incompressible creeping Newtonian flow (visco-elastic elaids will be considered in a second part). The method requires the solution of two simultaneous integral equations on the interface between the two fluids and the confining solid boundary. The method is illustrated through the simulation of the deformation of a drop as it is driven by the ambient flow inside a convergent channel. The accuracy and convergence of the method are assessed by varying the time increment for a given number of boundary elements. The influences of the degree of channel convergence and viscosity ratio are investigated. Circular as well as elliptic initial drops are also considered.

Frontiers in the science and technology of polymer recycling

Preface. 1. Introduction. 2. Fundamental Issues Pertinent to Polymer Recycling. 3. Reprocessing of Single Type Polymers. 4. Reprocessing of Mixture of Polymers. 5. Recovery of Chemicals and Energy. 6. The Way Forward. Index.

Structuring polymer blends with bicontinuous phase morphology. Part II. Tailoring blends with ultralow critical volume fraction

Abstract A hypothesis providing a guideline for the development of immiscible polymer blends with co-continuous phase structure at very low critical volume fraction of one component is postulated and experimentally verified. Based on a number of simplifying assumptions the following relation was derived: φ cr =k(λ γ ) 1−z /(θ b ∗ ) z where λ γ is a Deborah number and θ b ∗ is a dimensionless break-up time. The equation parameters, k and z are constant that depend on the flow field hence on the blending equipment. For the studies an internal mixer with Walzenkneter-type 30 mixing shafts was used. For this equipment the experimental values of the equation parameters, k=1801 and z=2.01, were found.

A boundary element analysis of planar drop deformation in the screw channel of a mixing extruder

The influence of shear and elongation on the planar deformation of a drop is examined as it is driven by the ambient flow in the screw channel of a continuous mixer. Viscoelastic fluids are considered, and a boundary-only formulation is implemented. The effects of viscosity, elasticity and initial position of the drop on the motion of the drop are investigated. It is found that the drop may or may not always deform indefinitely as it is subjected to the shear flow induced by the relative movement of the barrel. Indeed, it is shown that if the drop is placed close to the entrance, it tends to get entrained towards the core region between two flights no matter how close to the barrel is its initial location. If, on the other hand, the drop is initially placed far from the entrance (but always close to the barrel), shear effects tend to be dominant enough for the drop to undergo almost rigid-body rotation.

PROGRESS IN POLYMER PROCESSING

The plastics industry shows undiminishing expansion. On the global scale it is the fastest growing industry. Even when, at the turn of the century, the consumption of commodity resins in the advanced countries levels off, the large capital investments in the developing countries will more than compensate for the local slowdown. Production of commodity polymers during the next five years is expected to grow at an annual rate of: PVC 2.8%, PS 3.2%, LDPE 3.2%, HDPE 4.7% and LLDPE 9%. For the engineering resins the rates are higher: POM 5.1%, PA 6.1%, MPPE 10.1%, PC 10.4% and Polyesters 13.5%. The most rapidly expanding are the multiphase polymeric materials: alloys, blends and composites whose growth rate will be about 14% per annum. In recent years the plastics industry experienced evolutionary rather than revolutionary growth. This is apparent for all factors. There are no new outstanding polymers but a continuous improvement and maturing of both production and utilization of the 5–10 years old resins, such as PEEK or LCP. In commodity resins the advances are achieved in the type of catalysts which allow synthesis of newer and better grades (e.g. flexomers). Similarly the processing equipment undergoes a gradual improvement, increased automatization and loop control as well as growth of size; injection of 100 kg per shot is a reality. The true advances are made in compounding and die design. For example, using the lubricated die one can extrude materials, e.g. UHMWPE, by the process which more resembles metal forming than classical plastics extrusion.