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
Thermoplastic Paint (a.k.a. Film Finish, Paint Film, Dry Paint): A Complementary Technology for Exterior Automotive Plastic
Thomas M. Ellison, Stephen P. McCarthy, Arthur K. Delusky, May 2000
Thermoplastic film technology and a new plastic molding process, under development in a joint effort by ValTek and U Mass Lowell, combine to offer reductions in system cost, total emissions and weight for automotive Class A" exterior panels in the new millennium. The recyclable structural panels are fabricated using Class "A" film finishes in one step and targeted for vertical and horizontal automotive panels."
High Velocity 3 Point Bending Test Using an Impact Tower
Francois Barthelat, Hubert Lobo, May 2000
The idea of using an impact tower for 3-point bending for polymer testing has been developed before [1]. In this work the experimental method is refined. The vibrations are reduced by removing the ends of the specimen and by using a smaller span. Results are presented for a polypropylene. The modulus and the yield stress increase with strain rate, as predicted by viscoelastic consideration and by the Eyring theory for the yielding of polymers.
Biaxial Test Method for Characterization of Fabric-Film Laminates Used in Scientific Balloons
Magdi A. Said, May 2000
Space Structures that require light-weight materials with sufficiently high strength and environmental endurance have been in increasing demand since the early 1980's. However, the biaxial behavior of these structural materials under pressurized loading, is rarely found in the literature. An experimental investigation was conducted to develop a test method and hardware to characterize the biaxial behavior of a fabric-film laminate intended for use as a structural envelope for large balloons. The material tested is a composite laminate of three layers. The three layers are: polyester-based woven fabric, 6 microns film of polyester (Mylar type A) and 6 microns film of linear low density polyethylene (LLDPE). The laminate structure provides high strength to weight ratio. In this study, a test technique has been developed to measure the biaxial response of the material to known stress ratios. The information gained from the test can be manipulated to estimate Poisson's ratio and the development of a material structural model.
A Geometry-Based Model for Determining the Filling Time in Resin Transfer Molding Process
Faezeh Soltani, Souran Manoochehri, May 2000
A geometry-based model is developed for determining the fill time in resin transfer molding process. In this model, the preforms are assumed to be thin flat with isotropic and orthotropic permeabilities. The in-plane shape of the preform is arbitrary. The location of the vents, the maximum flow length, and the time required to fill the mold are calculated applying analytical solutions. The variety of preforms and processing conditions are used to verify the model. The mold filling time calculated by the model was in good agreement with those obtained using the C-MOLD filling simulation. Saving in the computational time was the key advantage of this model.
A Rapid Method for Prediction of the Vent Locations in Resin Transfer Molding Process
Faezeh Soltani, Souran Manoochehri, May 2000
A model is developed for predicting the location of the vents in isotropic RTM molds of various geometries. The preforms may contain holes and/or impermeable inserts. The location of the vents required to avoid trapping air bubbles are determined using neural network and geometric-based solutions. The neural network was trained with data obtained from simulation and actual molding experimentation. For a number of test cases, the performance of the method is compared to the prediction of vent locations obtained using a commercial mold filling simulation. It was found that the proposed method can predict vent locations with a good accuracy as compared to the filling simulation results. Applying the neural networks reduced the amount of computational time in comparison to the simulation methods.
Structure-Property Relationships for Propylene/?-Olefin Copolymers: Effect of Short Branch Length
Catherine Jung Hyun Cho, João B.P. Soares, Costas Tzoganakis, May 2000
A single active-site-type catalyst was supported onto silica and used to produce propylene/ a-olefin copolymers with high isotacticity and high molecular weight. The effects of different reaction conditions such as temperature, pressure and hydrogen content on structural properties were investigated. Several comonomers with varying length and bulkiness such as hexene, decene, octene, dodecene, hexadecene, eicosene, and styrene were copolymerized with propylene. With the knowledge of the reactivity ratios and the effect of different reaction parameters on polymer microstructure, copolymers with the same level of comonomer content and similar molecular weight were made with different comonomer types. The produced copolymers were analyzed for their structural and rheological properties using GPC, DSC, CRYSTAF, NMR and RMS. Thus, the isolated effects of comonomer type (length and bulkiness) on structural and rheological properties were studied and correlated.
Morphology Control of Ternary Polymer Blends Using Interfacial Tension
Minhee Lee, Costas Tzoganakis, Jeong-Min Kim, May 2000
Morphological studies for various ternary polymer blends were performed. The blends were prepared using a Haake batch mixer and analyzed using SEM and TEM. Interfacial tensions and spreading coefficients were used for predicting the blending morphology, and the predicted morphology was compared to the experimental results. The interfacial tensions were calculated from surface tensions at 20°C, and the temperature dependence of the surface tension and a harmonic mean equation were also used. All blending systems chosen in this experimental work were expected to have a minor component (B or C) encapsulated by the second component (C or B) in the matrix (A). It was found that many ternary blends (PC/PMMA/PE, PMMA/SAN/PBT, PBT/SAN/PC, etc) agree with the predicted morphology. However, some blending systems show an opposite encapsulation behavior (SAN/PC/PMMA) or a complex blending behavior (PP/PC/SAN).
Coloration of Polytrimethylene Terephthalate Fibers with Pigments and Polymer Soluble Dyes
Roger Reinicker, Adriano Pangelinan, Imrich Greschler, May 2000
Polytrimethylene terephthalate (PTT) is a recently commercialized polymer with both demonstrated and potential for increasing use in fibers for carpets and textiles. It is both dyeable in the conventional sense but also readily colored in the melt phase with pigments and polymer soluble dyes. This paper explores the methods used to mass color (solution dye) PTT, the pigments and dyes that can be employed, and the color and fastness results obtained with eleven selected colorants.
Dynamic Light Scattering Method for Determination of Shelf Stability of Liquid Colloidal PVC Stabilizers
Michael H. Fisch, Radu Bacaloglu, May 2000
Many liquid mixed metal stabilizers are colloidal microemulsions of water in oil. Their shelf stability is a function of the diameter of microemulsion droplets. Microdroplets with a diameter less than 50-60 nm and low tendency to aggregate are shelf stable. A fast procedure for estimation of shelf stability of liquid stabilizers for PVC based on determination of microdroplet diameters was developed.
Fatigue Behavior of Discontinuous Glass Fiber Reinforced Polypropylene
Mustafa Sezer, Ahmet Aran, May 2000
The fatigue properties and mechanism of 30% wt. short glass fiber reinforced chemically coupled and uncoupled polypropylenes were determined. Depending on the degree of damage, debondings effect the load transfer to the fibers. Final fracture occurs if the number of non-loaded fibers in one cross-section increases up to the critical value. When the fatigue data was presented as S-N curves, both materials have not showed any endurance limits. The microstructural mechanisms were discussed by help of SEM observations.
Effects of Processing Conditions on the Failure Mode of an Aliphatic Polyketone Terpolymer
Nicole R. Karttunen, Alan J. Lesser, May 2000
The yield and failure response of an aliphatic polyketone terpolymer subjected to multi-axial stress states has been studied, with a focus on the effects of processing conditions on the failure mode. Testing has been performed on anisotropic hollow cylindrical samples of this semi-crystalline thermoplastic material. Samples were processed under 5 different extrusion conditions. It was found that the cooling rate has some effect on the failure mode, while the rate of extrusion is less significant. Possible processing effects that may account for the differences in behavior include residual stress, amorphous orientation, or crystal morphology.
Toughness Enhancement through Conversion of Cyclic Polybutylene Terephthalate to Linear PBT
Sam Miller, James Donovan, William MacKnight, Roger Kambour, May 2000
The fracture toughness of macrocyclic polybutylene terephthalate (simple ring molecules) and linear PBT is correlated with the size of the plastic zone at the crack tip, which is inversely related to the yield stress. Macrocyclic PBT (c-PBT) molecules have a lower melt viscosity than linear molecules of comparable molecular weight, making them easier to process. However, the cyclic molecules are highly crystalline, with a high yield stress, and consequently a lower toughness. A ten-minute heat treatment in the melt opens the rings, and allows molecular entanglement, causing lower crystallinity of the solid polymer, and increased toughness. Therefore, control of the molecular structure of PBT provides a polymer with low viscosity that can be toughened by an easy heat treatment.
Effects of PP-MMA Alloy and Impact Modification on Weathering Performance of Polypropylene
T.A. Glogovsky, M. Finnegan, May 2000
The weathering performance of polypropylene and a novel polypropylene/acrylic alloy with and without impact modifier was investigated. Accelerated weathering testing was completed using Xenon Arc Weather-ometer. Surface cosmetics (gloss and color change), microscopy, and FTIR were used to characterize the surface and bulk properties after exposure to accelerated weathering. Dramatic improvements in weathering performance were observed through the addition of propylene/acrylic alloys and a proprietary impact modifier to the base polypropylene homopolymer. The individual significance of the propylene/acrylic and the impact modifier on weathering performance were similar. The benefit observed with weathering when combining the propylene/acrylic alloy and proprietary impact modifier was additive with respect to weathering performance.
Prediction of the Weld Lines in Injection Molding Process Using Neural Networks
Faezeh Soltani, Souran Manoochehri, May 2000
A model is developed for the prediction of the weld lines in injection molding process. The position of the weld lines in a multigate cavity system, with holes and/or inserts in the part, are predicted using a neural network-based back propagation algorithm. The neural network was trained with data obtained from simulation and actual molding experimentation. For a number of test cases, the performance of the method is investigated on comparing predicted weld lines with those obtained using a complete mold filling simulation. It was found that the proposed method can predict the position of the weld lines with a good accuracy as compared to the filling simulation. Applying the neural networks reduced the amount of computational time and eliminated the pre/post processing time as compared to simulation methods.
The Effects of Mold Filling on Living Hinge Performance
Patrick J. Brannon, Bart LiPetri, Carol M.F. Barry, May 2000
Filling characteristics of polypropylene living hinges and their performance were compared in order to create a model that will predict the quality of living hinges. In this study, three filling characteristics correlated to hinge quality: melt front advancement, skin orientation, and hinge fill time percentage. First, the melt front advancement; should be parallel to the axis of hinge rotation and free from discontinuities. Then, the skin orientation must be perpendicular to the hinge's axis of rotation. Finally, the most critical parameter was the hinge fill time as a percentage of the fill time for the part.
Numerical Simulation of Bi-Layer Extrusion Flow within a New Conical Extruder
Alp Sarioglu, Daniel Schläfli, André Luciani, Jan-Anders E. Månson, May 2000
In this study, the coextrusion flow in the die section of a new type of multi-layer extruder is determined. The prototype extruder used is based on a conical rotor-stator assembly. The extrusion of a range of individual layers of PEs was investigated. Numerical simulation, based on an axisymmetrical model of the assembly using an inelastic fluid model, was used to analyze the flow behavior.
Freeze-Thaw Durability of Composites for Civil Infrastructure
J. Haramis, K.N.E. Verghese, J.J. Lesko, May 2000
Freeze-thaw durability is a critical area that needs to be investigated prior to implementing composite material use in civil infrastructure. This work will examine the performance of pultruded vinylester/glass and epoxy/glass cross-ply laminates in different aging environments. Tensile test data encompassing strength, stiffness, and strain-to-failure on as-received" and moisture saturated material will be presented as well as saturation moisture uptake data. Discussion of continuing experimental work related to freeze-thaw cycling will also be addressed."
Laser Surface Modification of Polymers to Enhance Adhesion Part II-PEEK, APC-2, LCP and PA
S.M. Tavakoli, S.T. Riches, May 2000
Excimer lasers have been employed to modify the surfaces of a range of polymers to enhance adhesion. Considerable increases in joint strength were achieved as a result of laser treatment. Many lap shear joints, exposed to hot/wet environments, provided high retention of joint strength and durability. Laser-treated PEEK and APC-2 joints exposed at 50°C and 96%RH for several weeks, showed excellent resistance to ageing.
Stereolithography Inserts - Pros" and "Cons" to Use Tin as a Backfilling Material"
Aureo Campos Ferreira, Carlos Henrique Ahrens, Fernando Humel Lafratta, Ricardo Borges Gomide, May 2000
Stereolithography inserts shells for injection molding tools are filled in the backside, aiming to support high pressures and to improve the cooling efficiency on the mold. A common backfilling material used is an alloy of bismuth. However, there are other alternatives, such as tin, which has a higher thermal conductivity. This article discusses the pros" and "cons" to use tin as a backfill and investigates if it provides a better cooling condition improving mold's life."
Applications of Gas-Assisted Injection Molding and Injection/Compression Molding in Thinwall Molding
T. James Wang, Shia-Chung Chen, H.H. Chiang, May 2000
Gas-assisted injection molding (GAIM) and injection/compression molding (ICM) processes are studied and compared with the injection molding (IM) process for thinwall applications (also called thinwall molding). In this paper, analysts for these three processes arc carried out. A cellular phone part will be used as an example. Analysis results will be reported and comparisons of these three processes will be made. Injection pressure, clamp force and deformation will be used to evaluate these processes. Injection pressure and clamp force reduction in the GAIM and ICM processes and their effectiveness in packing will be emphasized.
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