Polymer Melt Fracture

The continually growing plastics market consists of more than 250 million tons of product annually, making the recurring problem of polymer melt fracture an acute issue in the extrusion of these materials. Presenting a pictorial library of the different forms of melt fracture and real industrial extrusion melt fracture phenomena, Polymer Melt Fracture provides pragmatic identification and industrial extrusion defect remediation strategies based on detailed experimental and theoretical findings from the last 50 years. Distinct microscopic photos Each chapter in this comprehensive volume covers a different aspect of the science and technology relating to polymer melt fracture. The book begins with a collection of optical and scanning electron microscopy pictures. These photos show distorted capillary die extrudates for a number of commercially available polymers. The authors present a brief introduction to the basic science and technology of polymers. They explain what polymers are, how they are made, and how they can be characterized. They also discuss polymer rheology, review the principles of continuum mechanics, and define linear viscoelastic material functions. Techniques for observing and measuring fracture Next, the book explains how polymer melt fracture is actually experienced in the polymer processing industry. It explains the various ways polymer melt fracture may appear during polymer melt processing in different extrusion processes. The authors provide comprehensive reviews of the polymer melt fracture literature, with chapters on experimental findings and the techniques used to observe and measure polymer melt fracture, and the influence of polymer architecture and polymer processing conditions on the onset and types of polymer melt fracture. Posing a hypothesis about the phenomenon, the book presents the current understanding of polymer melt fracture. Mathematical equations Recognizing the importance of models for simulations that may indicate potential solutions, the book discusses aspects of non-linear constitutive equations and microscopic theory and develops a macroscopic model, explaining the capabilities and limitations of this approach. The book presents an overview of pragmatic tools and methods that have been used to prevent the appearance of polymer melt fracture and explains how to use them to suppress defects.

Polymer Melt Fracture PicturesOptical MicroscopyScanning Electron Microscopy Polymer Characteristics PolymersPolymer Characterization General ObservationPolymer Rheology Continuum Mechanics Scalars, Vectors, and TensorsStress TensorStrain Tensors Equations of MotionConstitutive Equations General ObservationPolymer ProcessingExtrusion Injection Molding Rotational Molding Calendering General Observation Melt Fracture Experiments Constant-Pressure and Constant-Rate Experiments Flow Visualization Critical Numbers Melt Fracture Observation Change of Slope Wall Slip Compressibility General Observation Melt Fracture Variables Polymer Architecture Polymer-Processing Variables General Observation Understanding Melt Fracture Melt Fracture MechanismsThe Constitutive Approach General Understanding General ObservationAdvanced Polymer Rheology Molar Mass, Zero-Shear Viscosity, and RecoverableComplianceContinuous Models and Frame Invariance Microscopic ModelsMolar Mass Distribution and Linear Viscoelasticity General ObservationModeling Melt Fracture The Relaxation-Oscillation ModelCoupling RO and Constitutive Equations Slip-Boundary Conditions A Rheological Model Including Wall SlipBulk and Interfacial Viscosity Balance for Different PolymersFlow Curve and Melt Fracture RelationGeneral ObservationPreventing Melt Fracture AdditivesExtruder and Processing ConditionsDealing with Melt FractureGeneral ObservationIndex

Rudy Koopmans received his PhD in physical and macromolecular chemistry from the University of Antwerp in Belgium. He is a fellow in the Basic Plastics R&D organization of The Dow Chemical Company located in Horgen, Switzerland. Since joining Dow in 1983, he has held various R&D positions in Europe and the United States. His main R&D focus is on materials development, polymer processing, and developing innovative technology solutions to market needs and identified market trends. In addition, he holds a visiting professorship at Leeds University in the United Kingdom in the Department of Chemical Engineering. He has published more than 50 peer-reviewed papers in international journals and books, and is a holder of multiple patents. Jaap den Doelder received his MSc in applied physics and applied mathematics at Eindhoven University of Technology in the Netherlands. He received his PhD in applied mathematics at the same university in 1999 on the topic of polymer melt fracture. The same year, he joined The Dow Chemical Company in Terneuzen, the Netherlands. He has since worked on a variety of topics related to materials science and modeling of polymers, connecting application requirements to molecular design. He is currently a research scientist in Dow’s polyethylene business. Jaap Molenaar studied mathematics and theoretical physics at Leiden University in the Netherlands and wrote a PhD thesis on the field of solid state physics. For more than a decade he was involved in mathematics consulting. He received the Neways Award for his work on academic knowledge transfer to industry. He specializes in the modeling of dynamical systems in terms of differential equations and has published several books on these topics. His research focuses on fluid mechanics, in particular polymer melt flow. Recently, he became active in systems biology. He is a full professor in applied mathematics and the head of department for Mathematical and Statistical Methods for the Life Sciences of Wageningen University and Research Centre in the Netherlands.