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
Evolution of the Anisotropic Structure of Poly(phenylene vinylene) Films with Stretching
Runqing Ou, Robert Samuels, Xingwu Wang, Richard Gregory, May 2000
The evolution of the anisotropic structure of PPV films with stretching was studied by three characterization techniques: three dimensional refractive indices using waveguide, infrared dichroism and flatplate x-ray photography. The results show that the cast PPV film without stretching has a highly planar structure. One way stretching converts the film to a uniaxial structure.
Extrusion Blow Molding Process-Development and Optimization
Karel Kouba, Petr Novotny, Peter Gust, May 2000
This paper presents the application of CAE tools for a Blow Molding process. A description of the underlying theory is provided. The predicted thickness distribution for an example part is shown to have a good correlation with experimental measurements. The approach to parison thickness optimization is also demonstrated.
Simulation of the Micro Injection Molding Process
Oliver Kemmann, Lutz Weber, Cécile Jeggy, Olivier Magotte, François Dupret, May 2000
To predict the filling process of micro injection moldings, a dedicated 3 dimensional software is under development. The algorithm is based on automatic re-meshing of the varying flow domain. Currently, viscous flow calculations are performed, while visco-elastic effects will be addressed at a later stage. To verify the results, micro injection molding trials with different polymers were carried out. Therefore, new test structures, realized by means of the LIGA technique, were designed. Visco-elastic effects like unique shapes of the frozen flow fronts have been observed, which leads to a new interpretation of micro mold filling.
Vacuum Stamping of a Refrigerator: Identifying Problems through Numerical Simulation, Solving Them and Validating the Solution on the Production Line
Nikos G. Pantelelis, Thierry M. Marchal, Prodromos Megisidis, Laurent Fondin, Andreas E. Kanarachos, May 2000
Thermoforming is gaining more and more applications because of its comparatively easy and fast process. With thermoforming either small (yoghurt pots) or large (refrigerator panels) flat parts can be moulded and a complete description of the process can be found. On the other hand, to simulate the thermoforming process is a real challenge, as various factors have to be investigated and taken under consideration if we want to achieve a realistic simulation. At the present paper, a very complicated thermoforming process is simulated using finite element and other numerical tools and the results are compared to the real process. Moreover, problems occurred in the real process are solved using the simulation tool.
Extrusion of Polystyrene Microcellular Foam with Supercritical CO2
Xiangmin Han, Kurt W. Koelling, David Tomasko, L. James Lee, May 2000
The continuous production of polystyrene foam with supercritical CO2 is achieved by injection of CO2 into the extruder barrel at a certain pressure and rapid pressure release in the die. The effects of temperature, pressure, and die shape, are analyzed in detail. Fundamental work related to the foaming process is accomplished by modeling the phase equilibrium with the Sanchez-Lacombe equation of state and combining the equations of motion, the energy balance and the Carreau viscosity model to characterize the flow behavior. The experimental parameters were selected according to the Tg and phase equilibrium. The position of nucleation in the die was studied according to the simulation results via a computational fluid dynamics code (FLUENT).
Processing Glass-Filled Polyethylene on a Twin-Screw Injection Molding Extruder
David Bigio, Rajath Mudalamane, Yue Huang, Saeid Zerafati, May 2000
The mechanical properties of glass-fiber reinforced thermoplastics depends largely on the post-processing fiber length distribution. The traditional method of compounding in an extruder followed by injection molding causes considerable fiber attrition. In this study, the benefits of using a novel type of machine -the Twin-screw Injection Molding Machine (T.I.M.E.) - is investigated. The effects of operating conditions such as screw speed, glass-fiber content and extent of screw fill, on the final fiber lengths and distribution are studied. Optical microscopy and image analysis methods were used to analyze the processed parts.
Vibration Assisted Resin Transfer Moulding (VIARTM): A New Alternative Technique to Improve RTM Performance and Part Quality
Nikos G. Pantelelis, Athanasios Bikas, Andreas E. Kanarachos, May 2000
At the present paper a new system with the aim to improve the RTM process has been developed and presented. The system is based on the assistance of the resin flow with mould-inducing mechanical vibrations. Potential advantages of the proposed method are the improvement of the quality of the composite part (reduction of voids and reach areas), decrease of the filling time and/ or the maximum applied flow pressure. A test apparatus has been set up at NTUA to study the various mechanisms that relate the resin flow through the preform mat, the curing and the external vibrations. The project is progressing well and initial results are very promising and will be presented at the conference.
Specific Features of Dynamic Vulcanization and Properties of Thermoplastic Elastomers
Eduard V. Prut, Natalia A. Yerina, May 2000
The macrokinetic of dynamic vulcanizetion was studied. Criteria for selection a cross-linked system and condition for conduction one-step dynamic vulcanizetion were suggested. The influence of the ratio of the basic components, the content of plasticizer and mineral filler on mechanical and processing properties of thermoplastic vulcanizates (TPV) was investigated. The ageing of TPV was connected with recrystallization of polypropylene (PP). The mechanism of TPV's deformation is proposed.
Practitioner Training Program for Troubleshooting Injection Molded Part Defects
Amy Schickline, Jennifer Schmidt, May 2000
The objective of this paper is to document our study of injection molded part defects. The study of the defects is necessary in developing a training program for technicians and engineers. With this program one will be able to understand the causes of the defect and the steps required to eliminate it.
Blend of Post Industrial ABS and PMMA Improves Thermal and Impact Properties
Michelle J. Mikulec, Tony Brooks, May 2000
The recycling of post industrial ABS and PMMA was investigated. A material compound consisting of 100% post industrial (PI) recycled ABS and multicolored acrylic (PMMA) scrap from a manufacturing plants was blended and extruded. Test samples were injection molded and the test results were correlated to virgin material. Additionally, the material was used in injection molding of rear lamp housings in black and gray colors. The test results and economics are promising.
A Novel Ionomer for Nylon Modification
Richard T. Chou, May 2000
A new family of Surlyn® ionomers containing reactive functional groups is being developed for polymer modification, e.g., modifying nylon for blow-molding applications. Compared to existing ionomers, the new ionomers exhibit a higher degree of compatibility with nylon. One of the unique features of the new modifier is that the new ionomers can be dispersed in nylon in an extremely fine particle size and narrow size distribution. This has a profound effect on both the melt rheology and the mechanical properties of the modified nylon. Most significantly, the new ionomer imparts a truly shear thinning melt viscosity of the modified nylon 6. The paper discusses the dispersion of the new ionomer in nylon 6 as analyzed by SAXS and TEM and the melt rheology behavior of the modified nylon 6 and briefly highlights the effectiveness of the new ionomer to modify nylon 6 for the demanding blow-molding applications.
The Creep Behavior of Poly(ethylene terephthalate) Bottles
Prakash S. Sonti, Saleh A. Jabarin, Michael R. Cameron, May 2000
Room temperature viscoelastic behavior of PET beverage containers was studied. Internal pressures result in an increase of the container volume. By assuming a cylindrical geometry, stresses can be computed and linear strains can be estimated from the volumetric changes. A time-dependent creep compliance was determined for 2-L freestanding containers under various internal pressure loads. These values match favorably with uniaxial creep measurements. From isochronous plots, the viscoelastic behavior is shown to be linear over a limited range of pressures. The creep curves show all the characteristics of simple linear viscoelastic models such as instantaneous elastic response, retarded elastic response and permanent deformation.
Measurement of Layer Deformation in Coextrusion Using Unique Feedblock Technology
Joseph Dooley, Kevin Hughes, May 2000
Multilayer coextrusion is a process in which two or more polymers are extruded and joined together in a feedblock or die to form a single structure with multiple layers. These layers should be uniform in thickness across the structure for best performance. However, layer thickness non-uniformities have been observed in many coextruded products. Previous work has shown these layer thickness variations can occur due to viscosity differences between the polymers in the layers and/or elastic effects that introduce secondary flows. The objective of this work was to experimentally measure the secondary flow velocities in a square channel using a unique coextrusion feedblock that produces annular rings instead of planar layers.
Enhanced Performance via Ester Lubrication of Rigid PVC Formulations Modified with Chlorinated Polyethylene
L.J. Effler, N.R. MacMurdo, G.R. Marchand, May 2000
In traditional calcium stearate/paraffin wax systems, higher levels of wax leads to lower melt temperatures, higher gloss, and higher impact properties of the extruded sheet or profile. Unfortunately, higher levels of wax also leads to longer PVC fusion times, and an increased tendency to develop die plate out. However, recent work with ester lubricant systems, in PVC formulations using chlorinated polyethylene, have shown that lower extrusion temperatures, pressures and torque can be achieved without sacrificing fusion time or increasing the risk of die plate out. All while maintaining or enhancing gloss and impact properties.
Electrospun Nanofibers of Electronic and Photonic Polymer Systems
C. Drew, X. Wang, K. Senecal, H. Schreuder-Gibson, J. He, S. Tripathy, L. Samuelson, May 2000
Electrospinning employs strong electric fields to create nanometer scale fibers. The fibers are collected as a non-woven fiber membrane with a very large surface area to volume ratio. Sulfonated polystyrene, enzymatically synthesized polyaniline and blends thereof, and dye-sensitized composite polymeric systems were electrospun and studied to optimize fiber formation. It is expected that these types of electrospun materials will find potential use as new lightweight electronic and photonic materials in numerous device applications.
A Study on the Poly(ethylene naphthalate)/Poly(ethylene terephthalate)-Poly(ethylene naphthalate) Copolymer Blends
Whanki Kim, Ho-Jong Kang, May 2000
Poly (ethylene naphthalate)/Poly (ethylene naphthalate)-poly (ethylene terephthalate) copolymer [PEN/(PEN-PET)] blends were investigated. It was found that introducing PEN-PET copolymer to PEN/PET blending system instead of using PET caused the lowering of transesterification reaction in melt mixing as compared to PEN/PET blends. As the duration of mixing gets longer, the transesterification difference between PEN/PET blends and PEN/(PEN-PET) blends becomes more evident. The increase of transesterification in PEN/(PEN-PET) blends with increasing mixing time resulted in the decrease of melting temperature, while glass transition temperature increased. In addition, our time resolved light scattering data shows that slower crystallization could be obtained in PEN/(PEN-PET) blends as compared to PEN/PET blends.
Thermal Analysis during Epoxy Casting Process for Joint Units of High Voltage Cable
Hon Seong Koo, Seong Jin Park, Won Bae Kim, Cheol Min Kim, Young Kil Ha, Young Seong Kim, May 2000
The temperature distribution and the degree of cure in an epoxy system during the casting process, which is used in the connecting unit of high voltage cable, have been simulated using the FE solver of MARC including the programmed routines. The curing kinetics of the epoxy system used in the casting process was determined by DSC test, which was used as material input data of the developed program. To verify the developed simulation program, we have compared the simulated results for the simple model problem with those simulated by C-MOLD. The simulation results of real epoxy system for the connecting unit of the 400 kV cable, which is currently under development, are also presented for various processing conditions.
Development of 0.5 mm Super SO DIMM Connector with Computer Simulation Tools
Shiu-Chun Lin, Jian-Ming Yang, Wen-Li Yang, Rong-Yeu Chang, Li-Shen Chen, Chun-Shin Huang, May 2000
Super Small Outline Dual Inline Memory Module (SO-DIMM) is widely employed in the design of next generation notebook PC and portable electronic devices. The maximum warpage of the injection-molded connectors are required to be a low as 0.1mm in order to be compatible with the SMT (Surface Mount Technology) process. Design of Experiment method and computer simulation were utilized to investigate the complex interaction among final dimensions, mold design, grade of liquid crystalling polymer and injection molding conditions. By using the L9 orthogonal table, the most critical factor affecting the warpage was identified. The effects of other factors were also discussed.
A Fast Approach to Automotic Runner Balance
Kun-Chih Chen, Rong-Yeu Chang, David C. Hsu, Alice S. Lin, Kelly Lu, May 2000
Runner balance is one of the most important issues to be addressed for multi-cavity mold in the mold design phase. Poor runner sizing will lead to Christmas tree filling pattern and hence different residence time of plastic melt on each cavity. This leads to excessive packing pressure on small cavity and part weight variation. This problem becomes more crucial for the so-called family mold. In this work, the concept of flow balance index (FBI) is proposed to address this problem. Real industrial cases are studied by this new approach and are verified by molding trial results.
A Novel Computer Simulation Technology for the Cooling Analysis of Complex Injection Molded Parts
Rong-Yeu Chang, Shin-Hui Huang, Wen-Li Yang, I.Y. Chen, C.C. Lai, May 2000
Cooling analysis has been the biggest obstacle in the simulation of the injection molding process, mostly due to the loss of convergence and enormous computation efforts encountered in the conventional boundary element method (BEM) approach. However, cooling analysis is not only essential in designing cooling channel layout, but also in optimizing the overall accuracy of filling, packing and warpage analyses. Fast Finite Element Method (FFEM) has been proved to provide excellent computation efficiency over the conventional BEM. A case study of complex car panel with FFEM is discussed in this paper.
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