SPE Library
The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Conference Proceedings
Characterization of Amorphous and Crystalline Orientation in Polyethylene Films
Rajen Patel, Theresa Hermel-Davidock, Rajesh Paradkar, Brian Landes, Lizhi Liu, Mehmet Demirors, Ken Anderson, May 2006
Molecular orientation in amorphous and crystalline phases affects tear and dart properties of polyethylene films. This paper will describe FTIR, X-ray, shrinkage and shrink tension methods for measuring orientation. Orientation and properties of the films will be correlated to molecular structure.
Understanding Why Adhesion in Extrusion Coating Decreases with Diminishing Coating Thickness, Part II: Non-Porous Substrates
Barry A. Morris, May 2006
It is well known that in the extrusion coating process, adhesion to aluminum foil and other non-porous substrates decreases with decreasing coating thickness. Several hypotheses are proposed for the source of this decrease, including a reduction in time in the air gap, faster cooling in the air gap, more rapid quenching in the nip and stress imposed during drawing. Modeling and experimental results show that cooling in the nip and stress have the greatest impact.
Using Solid Freeform Fabrication (SFF) Techniques for Mold Cores and Cavities
Walter Michaeli, Michael Schoenfeld, Carlos Ahrens, May 2006
Opportunities and limitations using SFF-techniques to design mold inserts are presented in this paper. With the aid of SFF it is possible to generate almost any cooling channel layout in mold cores. Therefore, a better targeted, faster heat removal and simultaneously better temperature homogeneity are feasible. Especially in localized Hot-Spot areas SFF techniques are able to improve the heat exchange. However, specific characteristics (pressure drop, thermal homogeneity, mechanical behavior) have to be considered.
The Long Term Behavior of Organotins in PVC Pipe
Richard W. Johnson, Michael B. Clark, May 2006
Organotin stabilizers have been used in PVC pipe for many years. These pipes are tested when made to insure that the level of organotin leaching from the pipe does not exceed a specific maximum value. This paper examines the fate of the organotins after prolonged use in PVC pipe.
Lubrication Mechanism in Poly(Vinyl Chloride) Compounds: Understanding Three Distinct Roles of Lubricants
James W. Summers, May 2006
Poly(vinyl chloride) (PVC) compounds require metal lubrication and polymer to polymer lubrication for good processing performance. This paper helps understand the lubrication mechanisms and roles. The lubricants’ roles are defined in terms of 1) metal release, 2) PVC primary particle to PVC primary particle flow unit lubrication, and 3) synergistic slip in a layer working with the first two functions of the lubricants. The optimization of these lubricant functions requires a combination of lubricants (surfactants) of various structures.
A Solution for Rupture of Polymeric Sheet in Plug-Assist Thermoforming
Hosseini Hossein, Berdyshev Boris Vasilivich, May 2006
Rupture of polymeric sheets is one of the practical problems during plug-assist thermoforming. This defect may occur both in the stage of mechanical stretching with plug, and in vacuum or pressure thermoforming. The results shown in our work not only leads to the understanding of the cause of this problem, but also enables us to formulate calculation of parameters that affect rupture of polymeric sheets during plug-assist thermoforming for production of axisymmetric polymeric articles.
Effect of Injection Molding Process Parameters on the Morphology and Quality of Microcellular Foams
Jingyi Xu, May 2006
The effects of injection process parameters for microcellular foams are investigated by two stages: plasticizing to make single-phase solution, and molding to make microcellular foam. The quality of the foam is evaluated by the morphology. It is obvious that the parameters from these two stages have different effects on the quality of the foam. The quantity analyses of molding and plasticizing parameters result in some new injection processing guidelines for the quality of microcellular foams.
Effects of Gas Content and Pressure Drop Rate on Foaming
Siu N. Leung, Chul B. Park, May 2006
Computer simulations of polystyrene (PS) /carbon dioxide (CO2) batch foaming processes were conducted to elucidate the effects of gas content and pressure drop rate on cell-nucleating and growth phenomena. The simulation results were carefully compared with in-situ visualization data obtained experimentally. The results indicate that increases in both dissolved gas content and pressure drop rate will augment the final cell density, reduce the average cell sizes, and improve the bubble size uniformity.
Accelerated Quality Assurance Tests for PE Pipe Grades
Gerald Pinter, Markus Haager, Reinhold W. Lang, May 2006
Three different lots of two PE 100 materials were investigated with fracture mechanics procedures under cyclic and impact loads. Lot-to-lot variations in the materials crack resistance were found and a correlation to crystallization kinetics (stepwise isothermal segregation), melt flow rate and density measurements could be established. The used characterization techniques are quick and inexpensive tests and have the potential to be included in quality assurance procedures.
Organoclay Networking in Polypropylene-Clay Nanocomposites
Mark A. Treece, James P. Oberhauser, May 2006
This report discusses the networking of organoclays and its influence on the rheology of polymer-clay nanocomposites. Small amplitude (SAOS) and steady state rheological experiments are systematically performed to study the effect of flow and thermal history on solid-like formation dynamics in a 3wt% polypropylene-clay sample. Results indicate that the kinetics of network formation increase with temperature, while the application of a sufficiently large deformation will irreversibly weaken the clay network.
Effect of Artificial Defects on the Fatigue Behavior of RTM Laminates
Gerald Pinter, Elisabeth Ladstätter, Reinhold W. Lang, May 2006
The effect of artificial defects (delaminations, notches) on the tensile fatigue behavior of RTM laminates was evaluated based on the comparison of cycles to failure at different stress levels, the stiffness decrease during the tests and isocyclic stress-strain curves. A reduction of cycles to failure could be found. Moreover the deformation contributions caused by visco-elastic effects and by cumulated damage during the fatigue tests could be assessed and compared.
Multiphase PP Blends for Automotive Interior: Composition Effects on Surface Structure and Scratch Resistance
Doris Machl, Christelle Grein, Klaus Bernreitner, May 2006
This paper will outline surface properties like scratch and gloss performance in PP/EPR blends consisting of a PP matrix and a dispersed EPR phase with crystalline PE core particles. A brief overview of the influence of intrinsic polymer parameters and processing conditions will be given.
How to Handle Being Restructured
Roger F. Jones, May 2006
Many professionals at some point in their careers find themselves at a dead end or restructured out of a job. This is the time in life to think about new directions, maybe to become a musician or painter, but more likely to go in business for yourself. Whether such a move would involve building your own manufacturing company or offering professional services as a consultant will depend on an individual’s personality traits, professional training, experience, and accomplishments. This paper describes ways to make a successful transition from professional employee to professional entrepreneur.
Molecular Diamonds®/Polymer Nanocomposites
Arun Ghosh, David A. Schiraldi, May 2006
Diamondoid nanofillers, found in natural gas/petroleum streams, have face-fused diamond crystal lattice cage. These diamond-like structures of these materials lead to their stability, strength, and rigidity. The diamondoids were used as additives in polypropylene, cyclic olefin copolymer and polycarbonate. The diamondoids examined in this study consisted of pure diamantane, triamantane, the tetramantane isomer, and a methylated tetramantane mixture. Effects of diamondoids on stress-strain, thermal, optical and morphological properties of polymers were studied.
Effect of Nano Particles on Foaming Behaviors of PP
Wenge Zheng, Y.H. Lee, Chul B. Park, May 2006
This research investigates the foaming behaviors of polypropylene (PP) and PP/clay nanocomposites blown with supercritical CO2. The cell nucleation and expansion behaviors of the PP-based nanocomposite foams are studied at various clay contents and die temperatures. The effects of the nano-particles on the cell morphology, the cell density and the expansion ratio of the PP/clay nanocomposite foams are identified.
Material Optimization of PA12 Laser Sintering Powder to Improve Surface Quality
Ernst Schmachtenberg, Michael Schoenfeld, Thomas Seul, May 2006
Laser Sintering can be an alternative for small lot production. However, the surface roughness does not always meet the specifications without finishing. An encapsulation of Laser Sintering particles with surfactants can significantly improve the quality of Laser Sintering parts by improving the separation between melt and powder during the process.
Effect of the Model Properties Over the Injected Part Dimensions
M.V. Candal, R. Morales, May 2006
The influence of the elements number of a finite element mesh in the simulation results (weight and linear shrinkage along the length and width of a specimen) was studied. Besides, simulation results were compared with a mesh obtained from solids modelator software (CAD) and from simulator software (CAE). The convergence simulation results showed similar tendencies with the experimental ones. The modelator mesh gives a faster convergence than the simulator one.
Thermoforming Process Optimization by using the Experiment Design Technique
R. Morales, M.V. Candal, May 2006
The influence of process parameters in the final properties of a thermoformed part was studied. An Experiment Design (DOE) of fractional factorial 24-1 type was employed. Process variables studied were: sheet temperature, vacuum pressure, and cycle and delay time. The experimental results showed the delay time as the most important parameter to obtain good quality parts.
Employing Microwave Energy to Mold Thermoplastic Material
Yogesh Vakharia, Shrujal Vakharia, May 2006
The objective of these experiments is to test the effect of microwave energy on different kinds of tools like metal and composite, and explore the use of the tool that can be heated up in the microwave oven. Following the test result, we shall select the correct combination of tool, microwave power level and time period to mold the plastic. This process of molding thermoplastic material can be economical, quicker, neater, cleaner and more efficient as compared to conventional methods of heating like oven or gas fired heating.
Applicability of Polymer Process Models for the Simulation of Starch Processes
H. Potente, A. Thümen, N. Böhm, May 2006
In the plastics industry it is common to use simulation software tools for designing processes. In contrast there are even no software tools which are 100% suitable for performing these tasks in case of starch processes. In case of simulating starch processes these one-dimensional process models mainly meet one problem: the different material behaviour of starch. In the study at hand the applicability of the available process models was investigated.
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