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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M. Zatloukal, P. Štach, P. Liu, J. Vl?ek, P. Sáha, May 2002
Cogswell [1] and Wagner [2] methodology was employed to determine the rheological and tensile strength properties of two LDPEs and two metallocene LLDPEs resins through capillary and Haul-off (Rheotens-like) measurements. It has been shown that the tensile strength properties obtained by both methods yield almost the same values. Moreover, these values can be correlated to the drawability in tubular film blowing for corresponding materials.
Because of the good light-weight potential, the good resistance against corrosion and a good permeability for electro-magnetic waves more often SMC parts will be used in european automotive applications. As a result of varying qualities of the SMC prepreg or paste there exist still problems during the compression molding process.The paper discusses the used measuring methods for quality control and the influence of aging effect, which occurs during the storage of Sheet Molding Compound (SMC), on the viscosity and the curing behavior of a LP-SMC paste.
This paper discusses the fundamentals of root cause analysis in identifying a failure, investigating its causes, and suggesting the corrective actions. Examples of hinge failure analysis are discussed. A descriptive statement of each failure is formulated followed by the suggestion of its probable causes and their investigation. Finally, the most probable causes are identified and recommendations are made. The cases at hand discuss the importance of material choice and part design to hinges failure.
Doing business in a different culture represents a formidable challenge. This paper is a case study covering marketing chemical products from post-Communist region of the former Czechoslovakia in the USA and Western Europe. Both positive and negative factors as well as lessons learned will be discussed.
Scratch behaviors of model polypropylene (PP) based blends are investigated. The model PP blends are PP, PP/ethylene-propylene rubber/talc, and PP/styrene-butadiene-styrene/clay. The effects of filler and rubber additions on the scratch behavior are correlated with material property and morphology of the PP blends. The PP/SBS/clay system, which contains sub-micrometer size clay inside the rubber particles, exhibits the best scratch resistance. Material parameters and surface characteristics that contribute to improvements in scratch resistance in PP blends are discussed.
Maintenance of a single screws dimensions during its service life is discussed due to the magnitude of the dimensional deterioration on overall process performance. Proper choice of materials of construction for screws can greatly increase service life. A simplified analysis for determining when to replace a screw is presented to assist in proper maintenance.
The dynamics involved during mold fill is complex and temperature dependent. Presently, the controllers for achieving a desired injection velocity setpoint profile are independent of processing conditions in plastic injection molding. A generic, online control procedure to re-define the controller parameters was developed from dynamic models to achieve good tracking of injection velocity setpoint profiles during simulations of mold filling. This generic control procedure provided an effective and systematic approach for any plastic material and different processing conditions.
Shear has been found an important nucleation parameter in the foam extrusion process. In this paper, further shear effects on foam properties are presented. At increased shear, foam expansion decreases, which suggests die swell promote competing mechanisms. Extension rate was found to correlate with expansion and compression strength. Also investigated was residence time at low shear to restore the shear thinning in the counter-rotating twin screw extruder. Shear and extension rate effects are addressed for foaming and foamed products.
In low temperature molding processes, shrinkage control and residual styrene are important concerns. The presence of low profile additives (LPA) can reduce the shrinkage of unsaturated polyester (UP)/styrene (St) resins cured at low temperatures under proper processing conditions. A systematic study was carried out to investigate the effect of reaction temperature, initiator systems, and modification of the resin system on structure evolution, final resin conversion, and shrinkage control of UP resins with LPA.
R. Zheng, P. Kennedy, J. Xu, L. Kishbaugh, May 2002
We present a simulation model for the MuCell® injection molding process in which supercritical fluid such as carbon dioxide or nitrogen is mixed with molten polymer and injected into the mold. The model accounts for the development of cells in the melt, their effect on viscosity and compressibility and the subsequent expansion of the melt to fill the cavity. Simulation results and their comparison with experiments will be discussed.
Two thermotropic liquid crystalline polymers were evaluated for use in rotational molding: Vectra A 950 and Vectra B 950. Material is typically prepared by grinding. When ground, even under cryogenic conditions, TLCPs tend to yield particles of high aspect ratio translating to low bulk density, poor granular flow, and incomplete densification. A process was developed to generate spherical particles of controlled size and distribution. Particle coalescence and densification characteristics were determined and compared against model predictions.
Soft contact lenses contribute up to 85% of the market for contact lenses in the U. S. The concept and the introduction of contact lenses, the history of the development of soft contact lenses and the materials currently used for contact lenses are discussed in this paper. The manufacturing method and the surface treatment are also briefly reviewed.
Uniformity in polymer melting in the screw-barrel system has very important influences on the quality of injection molded products. An experimental study on injection plastication is conducted with HDPE in a visual barrel system. Solid-bed break-up phenomenon is observed and analysed under different processing conditions.
A large number of improvements in plastics joining technology have been stimulated by the end user. The influence of the car industry's suppliers and the car industry itself, along with the telecommunications and construction industries and medical technology were reflected in recent developments that have been presented at the K-fare in Düsseldorf/Germany at the end of October 2001.
In two-stage extrusion, the pumping section must be sized to produce the needed delivery pressure of the extruder. A method of calculating the channel depth so that the desired pressure is achieved and that the stability of the flow is optimized has been developed. Data for an example are given.
Melt spinning of cyclo-polyolefins is presented. The birefringences of the melt-spun filaments were determined and contrasted with spinline stress. These were found to be much lower than polycarbonate and polystyrene filaments melt spun under the same conditions. The birefringence was represented in terms of polymer chain orientation.
Changchun Zeng, Xiangmin Han, L. James Lee, Kurt W. Koelling, David L. Tomasko, May 2002
Exfoliated and intercalated polymer/clay nanocomposites were synthesized and used to prepare nanocomposite foams, using CO2 as the foaming agent. The foam structure was observed by scanning electron microscopy (SEM), while transmission electron microscopy (TEM) was used to observe the detailed clay distribution. The effect of clay dispersion and clay concentration on the cell structure was investigated.
Luis C. Mendes, Ana C.M. Costa, Ailton de S. Gomes, May 2002
In order to use linear low density polyethylene (LLDPE) as external duct lining of oil pipes, we have evaluated the aging of this polymer. The experiment has been carried out under accelerated UV fluorescent lamps exposure, during 336 hours.We focused our investigation on changes on mechanical properties occurring over the aging process.The LLDPE studied was mixed with peroxide in order to modify its properties.
Radu Bacaloglu, Michael H. Fisch, Ulrich Stewen, Ilze Bacaloglu, Edward Krainer, May 2002
Capillary rheometry allows monitoring PVC thermal and shear stress degradations separately. Based on testing of PVC compounds with a capillary rheometer, stabilizers can be efficiently optimized to reduce both degradation processes. Capillary rheometry is an important tool to improve productivity of PVC processing further at high shear rates.
This study will compare the use of several different transfer modes during the filling phase of the injection molding process. These modes include screw position, hydraulic pressure, and melt pressures within the cavity and nozzle. The modes will be investigated by using cavity pressure consistency when regrind and check ring wear are introduced. There are 4 transducers located in different areas within the cavity that will measure the peak pressures.
Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
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