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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
Solid Conveying Model for Determining the Throughput for Ultra-Short Single Screw Extruders with Spiral-Groove Cylinder
H. Potente, F. Reckert, May 2001
Dimensioning conventional single screw extruders, axially grooved cylinders are utilised to achieve increased throughput and an operating performance being independent of the counter pressure by increasing the friction of the material on the cylinder wall. In contrast to this, the geometry of the grooves in an ultra-short single screw extruder [3] with combined conveying and plasticising areas serves to increase material friction and to realise a mass flow. For this reason, the models of the material throughput for conventional single screw extruders are not unconditionally applicable for this extruder type. It is not possible to consider only one volume element in the screw channel for formulating the model. Instead, a combined system of various volume elements that move at different speeds and in different directions must be taken into consideration.
Dynamic Mechanical Analysis of Aromatic Polyamide/Ethylene-Propylene-Diene Terpolymer Laminates
Geralda Severe, Donovan Harris, Christopher Macosko, May 2001
The dynamic mechanical analysis of aromatic polyamide, ethylene- propylene-diene terpolymer (EPDM) and 256-microlayer laminates of aromatic polyamide and ethylene-propylene-diene terpolymer have been investigated at different temperatures. Furthermore, microscopy was used to correlate the thermomechanical observations with the morphology. The aromatic polyamide studied is a random copolymer of isophthalic acid, 12-aminododecanoic acid and bis(4-amino-3- methylcyclohexyl)methane. The 256-microlayer laminates were prepared by using microlayer co-extrusion technology. Increasing compatibility between the aromatic polyamide and EPDM showed minor improvement on the dynamic response for the laminates.
On-Line Viscosity Control for the Injection Molding Process
G. Sherbelis, R.G. Speight, May 2001
Variation in material viscosity during production is a well-documented phenomenon. The variation can be caused by regrind usage, humidity level, factory temperature variation, and raw material batch to batch variation. Today's quality control systems react to viscosity changes by maintaining certain parameters of the process constant. These control systems operate without directly effecting the material viscosity, for example trying to maintain a reference peak cavity pressure profile. Direct control of material viscosity by means of melt temperature is one concept being explored. Compensation is required for the effect of temperature changes on density and material solidification times. The paper examines the ability to control part weight and dimensions in a production environment, as part of an on going research programme in the Moldflow laboratories.
Automated Injection Molding Machine Optimization
R.G. Speight, L. Reisinger, C. Lee, M. Spence, May 2001
Injection molding manufacturers are increasing their requirement for consistent and optimised approaches for machine set-up. The ultimate aim of process monitoring and optimization within the manufacturing environment is (i) to develop molds with large processing windows, so there is a high confidence of producing good parts consistently with a higher overall set-up efficiency, or (ii) to achieve 100% automatic inspection and quality control of all molded products, in a straight forward and non-complicated manner. It is a requirement that no unacceptable moldings are passed on to the customer. An automated process monitoring and optimization strategy offers a key opportunity to the polymer processing industry to gain an understanding of its processes, and by this provide greater clarity for the machine operators. This paper presents a case study verifying the automated machine set-up strategy of a new mold in a high-end molding facility, using a computer aided engineering control system.
Extracting Chemical Information from Atomic-Scale Imaging and Spectroscopy
G.S. McCarty, P.S. Weiss, May 2001
Scanning probe microscopes allow unprecedented views of surfaces. Here, we discuss our efforts to identify and to characterize atoms and molecules on surfaces and how the scanning tunneling microscope images these adsorbates. We are currently attempting to extend the spectroscopic capabilities of scanning probe microscopes in several ways. For example, recent advances in tunable microwave frequency AC scanning tunneling microscopy allow differentiation of some surface features and interrogation of single and bundled molecules. We are also able to map with nanometer resolution the emission of photons induced from nanoparticles induced by tunneling electrons. We are developing these and other local spectroscopic tools to determine the chemical, physical, and electronic properties of surface features and adsorbates while simultaneously measuring their chemical environment.
Nanometer-Scale Structural, Tribological, and Optical Properties of Ultrathin Poly(Diacetylene) Films
A.R. Burns, R.W. Carpick, D.Y. Sasaki, May 2001
The ability to create organized ultrathin films using organic molecules provides systems whose chemical, mechanical, and optical properties can be controlled for specific applications. In particular, polymerization of oriented mono- and multi-layer films containing the diacetylene group has produced a variety of robust, highly oriented, and environmentally responsive films with unique chromatic properties [1]. These two-dimensional poly(diacetylene) (PDA) films, where the conjugation runs parallel to the film surface, have previously been prepared in a variety of forms [2]. Of particular interest is the optical absorption of PDA due to its -conjugated backbone. A wide variety of PDA materials, including bulk crystals, thin films, and solutions, exhibit a chromatic transition involving a significant shift in absorption from low to high energy bands of the visible spectrum, thus the PDA appears to transform from a blue to a red color. In addition, the red form is highly fluorescent, while the blue form is not. This transition can be brought about by temperature [3, 4], binding of specific biological targets [5], and applied stress (mechanochromism) [6, 7]. In this paper, we discuss the Langmuir deposition of ultrathin PDA films and the subsequent measurement of their structural, optical, and mechanical properties at the nanometer scale. By altering the head group functionality, we can choose between mono- and tri-layer PDA film structures [8]. Measurements with the atomic force microscope (AFM) reveal strongly anisotropic friction properties that are correlated with the orientation of the conjugated polymer backbone orientation [9]. Furthermore, we can use the AFM tip or a near field scanning optical microscope (NSOM) tip to locally convert the PDA from the blue form to the red form via applied stress [7]. This represents the first time that mechanochromism has been observed at the nanometer scale. Dramatic structural changes are associated with this mechanochromic tr
Evaluating the Impact Behavior of Different Thermoplastics and Composites
Amjad F. Abu-Ali, Rabeh H. Elleithy, May 2001
The objective of this paper is to study the impact properties of different thermoplastics and composites by using different impact methods. The impact properties of Polyethylene (PE), Polypropylene (PP), Polyvinyl Chloride (PVC), Polymethylmethacrylate (PMMA), Acrylonitrile Butadiene Styrene (ABS), Ionomer, and PVC composite were investigated. The difference between uni-axial, bi-axial and tri-axial impact strength of the studied materials was illustrated. Impact load vs. displacement curves highlighted the difference between crystalline and amorphous thermoplastics and composite. In addition, the effect of short glass fibers on the impact properties was also demonstrated.
Screw Cooling Effects in Single Screw Extruders
Edward Steward, May 2001
Screw cooling has been used on occasional single screw extruder applications for many years. Most screws today are set up for cooling (have holes drilled down the screw shaft for some distance), but these days the cooling is seldom utilized. It would be helpful to have a general study of this parameter to prove where possible gains in performance are expected, or to obtain data to support why we should not be cooling the screw in some instances. This paper will give the results of a study of screw performance on several polymers where screw cooling was tested. The results of the non-cooled screw will be compared to screw cooling along the early portion of the screw as well as a fully cooled screw shaft. The tested screw will be one of today's barrier type screws and will allow conclusions as to the performance altering affects of screw cooling. The need to have this information documented in a concise form will be satisfied by this study.
Business Opportunities in the Czech Republic
J.G. Drobný, D. Pavelková, T. Saha, F. Trnka, M. Chovancová, May 2001
The Czech Republic, a country with a population of 10 million has a formidable chemical industry with a long tradition. The polymer processing industry is its important part and represents a number of unique technologies. One of the prime candidates for the European Union, expected to be admitted in 2005, it is a stable partner ready to be part of the global economy. With a highly skillful and productive workforce it represents a very good opportunity for trade offering a great variety of unique products. Because of this country's location in the center of Europe, it is an attractive partner for investment. This paper will deal with current trends and provides details about the industry.
The Influence of Rotational Shear Pultrusion on Fiber Concentration and Wet out of Long Glass Polypropylene
Larry V. Montsinger, May 2001
New technology was developed to impregnate continuous glass fiber with molten thermoplastic polypropylene for manufacturing long fiber compounds. A composite with a polypropylene matrix and glass fiber reinforcement was made by rotation of a die orifice chamber about an axially directed roving of continuous fiber in the presence of the thermoplastic melt. The rotation reduced the melt viscosity of the polymer by shear thinning, while dragging and directing the polymer into the fiber, thereby wetting and dispersing the fiber. Fiber concentration was strongly influenced by the rotational speed of the die in conjunction with the line speed of the strand. Fiber wet out, measured by the shear strength of the strand, was improved at higher rotational speed and line speed.
The Processing and Performance of Nylon 4.6, Polypropylene Oxide/ Polyamide (PPO/PA) and Polyetherimide (PEI) in Automotive Fuel Handling Applications
M.P. McCourt, G.M. McNally, W.R. Murphy, T. McNally, May 2001
This present work investigates the rheological properties and the effect of immersion in standard automotive fluids (an extension of SAE J2027) on the mechanical performance of a range of Nylons, Polypropylene Oxide/Polyamide (PPO/PA), and Polyetherimide (PEI). The rheological characteristics of Nylon 4.6., PPO/PA and PEI were investigated and the results showed significant decrease in shear viscosity at dwell times in excess of three minutes for Nylon 4.6. and PPO/PA. Injection moulded samples of the Nylon 4.6., impact modified Nylon 4.6., Nylon 12, PPO/PA and PEI were immersed in the standard automotive test fluids, Fuel C, zinc chloride solution and aggressive water. Subsequent mechanical analysis of the various specimens showed only slight decrease in the tensile modulus of the Nylon 4.6. after immersion in Fuel C, however significant weight gain and deterioration in tensile modulus were recorded after immersion in aggressive water. Dynamic Mechanical Thermal Analysis on the Nylon 4.6 showed only slight decrease in storage modulus (Log E') and Tg, after immersion in Fuel C. However a significant decrease in Tg by up to 80°C was recorded for samples immersed in aggressive water.
A Rational Way to Reduce Number of Colorants Used
Joseph M. Cameron, S.T. Greer, May 2001
The number of colors or colorants used in your operation takes on a life of its own, ever growing in size and complexity. There are valid reasons for the growth; to better match colors, satisfy a key customer, gain more heat or light stability, improve cost or processing properties, more reliable supply or to provide a specialty product. At the time each one is introduced we are typically under some driving force to satisfy a tactical need, what the heck its just one more item, and we lack the time to take a more strategic view. Next thing you know the number has grown from 80 - 100 items to 300 or more! So, do you really need that many colors? If you had fewer colors, your operations would be much simpler and simplicity implies better, less costly more reliable operating. So why not do the job with 50 colors. Well why stop there, why not 20 or maybe 16, shucks the rainbow only has 7, ROYGBIV. You know, we see all the colors on a TV screen or CRT & they are made from just Red Green & Blue, why not 3 colors? This paper will deal with the issue of what is the right number of colors, how you can go about getting there (and maybe staying there) and finally some of the benefits you might expect.
Chlorine Resistance Testing of Cross-Linked Polyethylene Piping Materials
P. Vibien, J. Couch, K. Oliphant, W. Zhou, B. Zhang, A. Chudnovsky, May 2001
The chlorine present in potable water as a disinfectant has been reported to reduce the lifetime of some plumbing system components. In this study the nature of the failure mechanism of a commercial cross-linked polyethylene (PEX) pipe material exposed in the laboratory to chlorinated potable water is examined. Water quality, or more specifically, chlorine level, is seen to have a significant impact on material performance. Test lifetimes are seen to be noticeably lower for chlorinated potable water, even at chlorine levels as low as 0.1 mg/L (ppm), than for non-chlorinated water. Through accelerated testing at multiple temperature and pressure conditions and the use of the Rate Process Model, a model to estimate the test lifetime of the PEX pipe material at end use conditions is developed. Based on this analysis the PEX pipe material examined in this study appears to have good resistance to chlorinated potable water.
Development of a New TPV for Bonding to Rigid Thermoplastics
Joseph E. Pfeiffer, Gary K. Lawrence, Kimberly S. Torti, May 2001
The development of a new flexible thermoplastic vulcanizate (TPV) that bonds to a number of different rigid polymeric substrates is introduced. Detailed bonding values will be given for this new material to ABS, polycarbonate, PC/ABS alloys, polystyrene, and polyester. Physical properties will be presented and compared to other bonding elastomeric materials. The processing recommendations are given for over molded or insert molded applications for this flexible bonding TPV. Potential applications for this flexible bonding material include bumpers for vacuum cleaners, soft touch grips for tools and utensils, and flexible housings for instruments.
The Use of Scanning Probe Microscopy to Determine the Surface Morphology and Mechanical Properties of Latex and Polymers
Robert F. Antrim, May 2001
An overview of Scanning Probe Microscopy (SPM) and it applications to polymeric materials will be presented. The SPM is a mechanical technique capable of both imaging and making physical measurements. The images provide rapid comparison of surfaces, while image reduction to a surface roughness value (Ra) allows numeric comparisons. Additionally, the interaction of the imaging tip with the surface, using the phase modulated mode, provides details on relative compliance of the surface. Images of compliance can be used to differentiate the spatial location of the different materials that make up the materials surface. The combination of the two techniques, topography and phase modulated, provides a very powerful tool for surface characterization.
Modeling Drop Size Distribution in Polymer Blend Injection Molding
Frederick R. Phelan Jr., Erik Hobbie, Hyunsik Jeon, Sharon C. Glotzer, Charles C. Han, May 2001
An approach for modeling the drop size distribution in the injection molding of polymer blends is developed. The simulation directly uses experimental data correlated to functional forms in the FIDAP fluid dynamics package. As an example, experimental data for droplet size and shape in a Polyisoprene /Polybutadiene system was measured using an in-situ optical microscopy instrument designed for studying complex fluids under simple shear flow. The data is collected in the flow-vorticity plane as a function of temperature and shear rate. Size and shape distributions were calculated from the digitized micrograph using standard image analysis software. The shear viscosity of the blends, as well as that of the pure components, was measured as a function of shear rate and temperature using a commercially available parallel-plate rheometer. From theoretical considerations, the simulation is expected to provide good estimates of drop size distribution for flows with large aspect ratios of flow length to thickness where entrance effects are expected to be negligible, and there are no regions of recirculation.
Investigation of Structure Development of Polyamide 11 and Polyamide 12 in Single Bubble Tubular Film Blowing
Sangkeun Rhee, James L. White, May 2001
The processibility of single bubble PA11 and PA12 films was investigated. The development of crystalline structure and chain orientation of polyamide 11 and polyamide 12 films in single bubble film blowing was studied by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXS), infrared (IR) spectroscopy and birefringence. DSC measurements of both films exhibited a spontaneous increase in glass transition temperature (Tg) and cold crystallization temperature (Tc) during aging at room condition with crystallinity and melting point remained constant. Single bubble PA11 and PA12 films exhibited triclinic and monoclinic ? crystals, respectively. The level of biaxial orientation was evaluated by calculating White-Spruiell biaxial orientation factors with pole figure data.
Structure Development in Uni- and Bi-Axial Stretching of Extrusion Cast Polyamide 12 Film
Sangkeun Rhee, James L. White, May 2001
Development of crystal structure, orientation and morphology in both uniaxial and biaxial stretching of extrusion cast polyamide 12 (PA12) films was carefully investigated. According to DSC measurements, aging of unstretched extrusion cast PA12 film at room condition raised both glass transition temperature (Tg) and cold crystallization temperature (Tc) without any considerable changes in crystallinity and melting point. The crystals of unstretched and stretched extrusion cast films were mostly monoclinic ? form. Stretching was carried out at various temperatures. By examining birefringences and WAXS flat films and pole figures, we found that the direction and level of molecular orientation was largely dependent on the extension ratios. SAXS showed that an increase in stretching temperature raised long spacings of lamellae. Annealing of PA12 films in formic acid solution raised crystallinity, melting point, level of chain orientation and long spacing of lamellae.
Drop Deformation and Breakup in Viscoelastic Polymer Blends
P. Singh, S.B. Pillapakkam, May 2001
A three-dimensional finite element code is developed for simulating viscoelastic two-phase flows. The viscoelastic fluid is modeled via the Oldroyd-B model. The exact governing partial differential equations are solved using the Marchuk-Yanenko operator-splitting technique. The two-fluid interface is tracked using the level set method. The code is used to study the deformation of drops in simple shear flows and bubbles in gravity driven flow. The effects of Deborah Number (De) and capillary number (Ca) on deformation is analyzed for De values ranging from 0.0004 to 16, and Ca ranging from 0.06 to 1.2. The numerical results show that the viscoelastic stresses near the drop surface increase deformation of a Newtonian drop in a simple shear flow as compared against Newtonian shear flow. For the case of a viscoelastic drop in a Newtonian shear flow the deformation is smaller than that for the corresponding Newtonian drop. The effect of viscoelasticity on deformation is more pronounced when De<~O(1). For a Newtonian bubble rising in a quiescent viscoelastic fluid, the extensional viscoelastic stresses pull out the trailing edge and the bubble develops a cusp like trailing edge in one view and a broad edge in the orthogonal view. The trailing end of a Newtonian bubble rising in a Newtonian liquid, on the other hand, is pulled inwards which leads to the drop taking an umbrella-like shape.
Direct Simulation of Sedimentation of Solid Particles in Viscoelastic Fluids
Mingyu Zhu, Howard H. Hu, May 2001
The sedimentation of rigid spherical particles in viscoelastic fluids is studied by using 3D direct numerical simulations, in the simulation, a Galerkin finite element formulation is used to solve the fully coupled motion of the solid particles and the fluid that is governed by an Oldroyd-B model. The movement of the particles is handled with an arbitrary Lagrangian-Eulerian technique in conjunction with a mesh update strategy. Effects of the parameters controlling the particle motion, which are the flow/particle Reynolds number, the Deborah number, and the solid-liquid density ratio are investigated. This work was supported by NSF through grant CTS-9873236.


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