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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The Infinitely Variable Dynamic Shear Mixer, IDMX
Mixing is one of the most important processes in the plastics industry. Two mechanisms occur in mixing: dispersive and distributive. Different types of mixers have been developed to fulfill both mechanisms.A special mixing unit was studied. Polycarbonate, ABS and regrind were investigated. The output of the mixer was investigated as a function of the screw speeds of the satellite extruders. Qualitative measurements were carried out to characterize the efficiency of mixing at different concentration levels of the components. Conclusions were made on the effect of the parameters of mixing.
Kinematics Model of Solids Conveying of LDPE with a Grooved Barrel
The kinematics model and solids conveying angle approach are used to analyze and calculate the solids conveying flow of LDPE with a grooved barrel. The result is an excellent prediction of solids conveying flow versus pressure for a grooved barrel extruder that does not require knowledge of friction factors.
Scratch Behavior of Polymer Coatings
A recent standardized scratch test methodology was applied to investigate the performance of a set of experimental acrylic coatings. Coating ductility and coating thickness were varied to study how the affect coating cohesive strength, adhesive strength and chipping resistance. The usefulness of the new ASTM scratch test for polymer coatings is discussed.
Characterization of Amorphous and Crystalline Orientation in Polyethylene Films
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
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
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
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
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
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
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
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
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
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
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
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.
Influence of Nanofiller Structure on Gas Permeability and Mechanical Properties of Epoxy/?-Zirconium Phosphate Nanocomposites
The morphology, gas permeability and physical/ mechanical properties of synthetic ?-zirconium phosphate based epoxy nanocomposites with variations in degree of exfoliation are investigated. The state of exfoliation and dispersion is directly confirmed by transmission electron microscopy (TEM) at different locations of the samples. The fundamental structure-property relationship of ?-ZrP reinforced epoxy nanocomposites as a function of degree of exfoliation of ?-ZrP layer structure is discussed.
How to Handle Being Restructured
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
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
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
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.
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