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.
The feasibility of In-Mold-Graining (IMG) has been proven through initial applications. Despite this, there is still a lack of detailed knowledge about the correlations that ensure the uniform reproduction of structured mould surfaces in thermoforming. The processing of multilayer laminates for soft-touch applications constitutes an additional challenge. In this paper, a heating concept for trilaminate materials (grainable layer/foam layer/compact layer) is presented to ensure an optimum forming result through a selective temperature distribution over the thickness of the material. The local pressure conditions between the trilaminate and the mold surface are investigated as a dominating influencing factor with respect to product quality.
In the production of microcellular panels by the solid-state constrained foaming process, the time needed for saturating ABS sheets with CO2 gas has been recognized as a bottleneck to developing a viable industrial process. Significant improvements in the productivity of this process are achieved by a) using partial (non-equilibrium) gas saturation and b) conducting the gas saturation in the retrograde region [1, 2]. Using a combination of these two approaches, the time required to reach the needed CO2 gas concentration in 4.75 mm thick ABS was reduced by 60%.Results on the panel density and the skin thicknesses achieved are reported and micrographs showing gradient microstructures are presented.
During the flow through an extrusion die the melt is deformed. Due to the viscoelastic behavior the melt stores portions of introduced shear and elongational deformation as stresses. At the die exit the stresses lead to die swell. The prediction of die swell is still a big challenge in plastics processing today. In an orifice die the flow conditions, stresses and die swell behind the outlet are calculated using the finite element analysis. Two different materials are modeled using different viscoelastic models. The calculated die swell is compared to experimentally measured die swell and the two different models are evaluated.
Walter Michaeli, Dirk Binkowski, Andreas Hegenbart, May 2007
Even though PET-bottles gain more and more market shares one crucial point is their insufficient permeation barrier. To overcome this disadvantage and to extend the shelf-life plasma assisted coating is a well known technique, which is industrially used. The coating is either deposited on the interior or exterior of the bottle. Typically barrier improvement factors (BIF) around 4 can be achieved for the gas carbon dioxide (CO2). A combination of both techniques leads to a significant increase of the BIF. Hence the technology enables applications for even more sensitive goods.
Purging of hot runners consumes an inordinate amount of time, materials and money. A study to get an efficient color or resin change makes use of the viscosity reduction by varying process parameters, and using purge additives that influence viscosity and self cleaning characteristics. This paper reports a part of a study on how that shear rate and the temperature in the hot runner manifold and barrel affect purging. The results show that very high and low melt temperatures in both of them affect purging. The best temperature setting is a low temperature in the hot runner manifold and a low temperature in the barrel.
For many electro-technical and automotive applications plastics components have to fulfill enhanced demands on their electrical and thermal conductivity. A novel material combination of metal fiber reinforced thermoplastics and low melting metal alloys allows a significant increase in the maximum filler content and therefore in the electrical conductivity in comparison to just solidly filled polymers, because the low-viscous alloy is already molten during manufacturing. The material can be processed economically to complex shaped parts by conventional injection molding. The material composition, the processing behavior and the resulting part characteristics will be discussed in this paper.
M. Zatloukal, R. Pivokonsky, M.T. Martyn, P. Filip, May 2007
The fitting/predictive capabilities of three models (eXtended Pom-Pom, PTT-XPP and modified Leonov model) are tested for both, steady as well as transient shear and uniaxial extensional flows of mLLDPE and HDPE. The applicability of these constitutive equations has been investigated from the coextrusion flow modeling point of view. Finally, the FEM and modified Leonov model has been employed for the stress analysis in the coextrusion flow domain and predicted stress fields have been compared with the stress measurements from the flow coextrusion visualization cell.
Patrick C. Lee, Wanrudee Kaewmesri, Jing Wang, Chul B. Park, Jantrawan Pumchusak, Rick Folland, Andreas Praller, May 2007
A systematic study is conducted to investigate the effect of die geometry (i.e., pressure and pressure-drop rate) on the cell-nucleation and growth behaviors of noncrosslinked high melt strength (HMS) polypropylene (PP) foams blown with supercritical CO2. The experimental results show that the cellular morphologies of PP foams are sensitive to the die geometry. The initial expansion behavior of the foam extrudate at the die exit is recorded using a high-speed CCD camera, which allows the study of die geometry effect on both initial expansion behavior and final cellular morphology. The effect of die temperature on the cell morphology is also studied.
Elise L. Kamieneski, S. Mandelbaum, P. Vemuri, R.A. Weiss, May 2007
Shape memory elastomers were prepared from mixtures of a sulfonated EPDM ionomer and fatty acid salts, FAS, (ZnOleate),. Physical crosslinks in the ionomer that arise from inter-chain ionic interactions provide a permanent shape, while the crystalline low molecular weight FAS provides the means for a temporary shape. The material can be deformed above the melting point (Tm) of the FAS and the new shape can be fixed by cooling the material under stress to below Tm of the FAS. Polar interactions between the ionomer and the FAS stabilize the dispersion of the FAS in the polymer and provide the continuity between the phases that allows the crystals of the FAS to provide a second network of physical crosslinks.
Ming Wei, Jia Shen, Carol Barry, Joey Mead, Sivasubramanian Somu, Xugang Xiong, Ahmed Busnaina, May 2007
In this work, we report the electric field assisted patterning of a conductive polymer, polyaniline (PANi), on an insulated and prepatterned template, followed by transfer of the pattern to a secondary substrate. Conducting PANi was selectively assembled on the negative electrodes of the template. After deposition, it was demonstrated that by compression molding, patterned PANi can be transferred to a polyurethane film. Unlike transfer by solution casting, however, the transfer of patterned PANi by compression molding was not complete. This may be the result of poor mobility of the polymer molecules. This work provides a promising nanomanufacturing approach for cost effective and high performance flexible nanoelectronics and biosensors.
Atakan Alt?nkaynak, Mahesh Gupta, Mark A. Spalding, Sam L. Crabtree, May 2007
Frictional forces (for temperatures less than melting or devitrification temperature) and viscous forces (for higher temperatures) have important roles on solids conveying and melting processes in single-screw, plasticating extruders. These forces are related to the shear stresses at polymer-metal interfaces. This paper presents the shear stresses and melting fluxes at four sliding velocities and at temperatures ranging from ambient temperature to 230°C for LDPE, ABS, HIPS, and LLDPE resins at a fixed pressure of 0.7 MPa.
The use of gas and/or liquid-phase carbon dioxide (CO2) with atmospheric plasma discharge surface pretreatment technology can remove micron and submicron particulates and hydrocarbon-based contaminations on plastics and metals. The cleaning process is based upon the expansion of either liquid or gaseous carbon dioxide through an orifice. The paper provides an understanding of the basic removal mechanism and provides experimental evidence of remarkable adhesion improvements relative to a broad range of applications in electrical, medical, and automotive manufacturing communities.
S.L. Villarroel, R.A. Morales, M.V. Candal, A. Gordillo, May 2007
The objective of this study was the development of a methodology to evaluate the influence of the fiber glass length contained in injection molded, flat PP specimens. The initial fiber length used was 12 mm. Flat specimens with 1mm of thickness were injected varying the injection conditions (injection velocity, melt temperature and cycle time). The mechanical properties were evaluated in longitudinal and cross-sectional sense respect to the flow direction in a universal testing machine, varying the position with respect to the injection point. When the cycle time and melt temperature were increased, variations in the size and fiber length distribution were not observed.
Nafaa Mekhilef, Sara Reynaud, Lotfi Hedhli, Gilberto O. Pasquariello, May 2007
In this work the effect of long chain branching in polyvinylidene fluoride on its rheology and blown film processing is investigated. Branched samples prepared by a conventional polymerization process were compared to commercial resins in terms of their rheological properties in shear and extensional flows. The branched samples showed an enhanced elasticity allowing a higher melt strength as well as strain hardening when subjected to extensional deformation. The enhanced rheological properties in the branched samples resulted in better processing performance in a blown film application where higher blow-up ratios and thinner films were achieved.
Nafaa Mekhilef, Lotfi Hedhli, Sara Reynaud, Gilberto O. Pasquariello, May 2007
This paper discusses the properties of high melt strength polyvinylidene fluoride (HMSPVDF) and their correlation with the thermoforming process. Resins having different molecular weights and extents of chain branching (CB) were prepared and compared to commercial resins considered linear polymers. The presence of chain branching enhances in the melt strength of the branched samples while the melt viscosity remains identical to the reference samples. HMSPVDF also shows a significant improvement in sag resistance over the reference samples and suggests better performance in thermoforming.
Hailing Yang, Wei Zhang, Ronald, D Moffit, Thomas C. Ward, May 2007
The T-peel fractured surfaces of bonded ethylene/1- octene copolymer films were characterized using atomic force microscopy (AFM) and analyzed by fractal analysis. A stitch-welding" autohesion mechanism was proposed on the basis of that fractal analysis results suggesting that amorphous chains interdiffused while unmelted interfacial crystal structures remain essentially unaltered during the autohesion process. The fractal dimensions and the characteristic sizes determined from the fractal analyses are strongly dependent upon 1-octene content bonding temperature and peel rate."
Shia-Chung Chen, Li-Chi Su, Cheng-Yi Chang, Hsin-Wei Hung, Wen-Hsien Yang, May 2007
In micro-injection molding, the preservation of precise micro-feature is one of the most important indications to ensure proper functionality and quality. A new technique, Induction Heating" which is advanced in heating up the mold quickly and accurately is adopted to control mold temperature during filling phase. This paper aims to analyze the technique specifically for a part with micro-feature of a high aspect ratio. Meanwhile it probes into the result of numerical simulation and actual experimental investigation. The result shows that some critical factors have a dominant effect on the molding mechanism and this result will be beneficial to the development of micro-injection molding technology."
Bruce F. Taylor, Timothy W. Womer, Robert Kadykowski, Robert A. Sickles, Jr., Luke A. Miller, May 2007
This paper compares the energy efficiency and control response of band-heaters with a new technology that uses non-contact induction to heat the barrel directly through an interposed layer of thermal insulation. Quantitative results from both laboratory injection molding machine runs and bench-top tests are reviewed. The effect of barrel diameter, surface condition and band-heater type on efficiency and control response are also considered, as are the implications of thermocouple depth.
A lot of plastic parts are made of fiber-reinforced engineering materials for its superior mechanical properties. Since the flow induced fiber orientation is complex 3D behavior, the final properties of the injected parts become very complicated. In this research, a ribbed flat plate geometrical model is conducted to examine the effect of fibers with various design consideration on injected parts both numerically and experimentally. Results show that the flow induced fiber orientation both numerically and experimentally in a good agreement. Also, it shows the fiber orientation will affect the final injected parts significantly.
Zhihua Guo, L. James Lee, David L. Tomasko, May 2007
Permeation properties are important for the design and implementation of polymer nanocomposites and polymer nanocomposite foam products. The literature is quite limited regarding permeation studies on these materials. In this paper, we focus on permeation properties of polystyrene nanocomposites (two types of nanoclay and carbon nanofiber) and their respective foams. Commercial instruments (PERMATRAN-C Model 4/41 and PERMATRAN-W Model 3/33 from Mocon) were used to measure steady state permeability coefficients of CO2 and water vapor at three temperatures: 10°C, 25°C, and 40°C. From these data permeation rates and permeation activation energy are compared based on nanocomposite morphology.
Kim McLoughlin Senior Research Engineer, Global Materials Science Braskem
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Kim drives technology programs at Braskem to develop advanced polyolefins with improved recyclability and sustainability. As Principal Investigator on a REMADE-funded collaboration, Kim leads a diverse industry-academic team that is developing a process to recycle elastomers as secondary feedstock. Kim has a PhD in Chemical Engineering from Cornell. She is an inventor on more than 25 patents and applications for novel polyolefin technologies. Kim is on the Board of Directors of SPE’s Thermoplastic Materials & Foams Division, where she has served as Education Chair and Councilor.
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Gamini has a BS and PhD from Purdue University in Materials Engineering and Sustainability. He joined Penn State as a Post Doctorate Scholar in 2020 prior to his professorship appointment. He works closely with PA plastics manufacturers to implement sustainability programs in their plants.
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Tom Giovannetti holds a Degree in Mechanical Engineering from The University of Tulsa and for the last 26 years has worked for Chevron Phillips Chemical Company. Tom started his plastics career by designing various injection molded products for the chemical industry including explosion proof plugs and receptacles, panel boards and detonation arrestors for 24 inch pipelines. Tom also holds a patent for design of a polyphenylene sulfide sleeve in a nylon coolant cross-over of an air intake manifold and is a Certified Plastic Technologist through the Society of Plastic Engineers. Tom serves on the Oklahoma Section Board as Councilor, is also the past president of the local Oklahoma SPE Section, and as well serves on the SPE Injection Molding Division board.
Joseph Lawrence, Ph.D. Senior Director and Research Professor University of Toledo
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Dr. Joseph Lawrence is a Research Professor and Senior Director of the Polymer Institute and the Center for Materials and Sensor Characterization at the University of Toledo. He is a Chemical Engineer by training and after working in the process industry, he has been engaged in polymers and composites research for 18+ years. In the Polymer Institute he leads research on renewably sourced polymers, plastics recycling, and additive manufacturing. He is also the lead investigator of the Polyesters and Barrier Materials Research Consortium funded by industry. Dr. Lawrence has advised 20 graduate students, mentored 8 staff scientists and several undergraduate students. He is a peer reviewer in several journals, has authored 30+ peer-reviewed publications and serves on the board of the Injection Molding Division of SPE.
Matt Hammernik Northeast Account Manager Hasco America
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Matt Hammernik serves as Hasco America’s Northeast Area Account Manager covering the states Michigan, Ohio, Indiana, and Kentucky. He started with Hasco America at the beginning of March 2022. Matt started in the Injection Mold Industry roughly 10 years ago as an estimator quoting injection mold base steel, components and machining. He advanced into outside sales and has been serving molders, mold builders and mold makers for about 7 years.
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