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 SPE Library is just one of the great benefits of being an SPE member! Are you taking advantage of all of your SPE Benefits?
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.
Stretch wrapping film has been used for over 30 years to protect and preserve food from moisture, dirt and abrasion. These films allow increased food shelf lives and give the package an appealing smooth and shiny appearance.Styrenic block copolymers can be blended with polypropylene and co-extruded with ethylene vinyl acetate to form multi-layer structures suitable for food wrap applications. These films offer an excellent balance of properties combined with a low density.
Granite-filled HDPE had lower tensile strength, modulus and elongation than unfilled HDPE. The reduction in properties is attributed to large particles that serves as stress concentrators. The mechanical properties of HDPE are improved with the use of adhesion promoters and use of metallic granite. A Taguchi design of experiment determined that the metallic component of the granite fines had higher tensile strength, modulus, hardness, and elongation at yield than the bulk granite fines.
The effects of long and short chain branching on the thermorheological behaviour of polyethylene are described. Long chain branched homo -polyethylene is thermorheologically complex and is most sensitive to temperature at low frequency. A technique for determining the activation energy spectra of thermorheologically complex materials is proposed. Short and long branches in the same system synergistically increase the zero-shear rate activation energy.
LDPE and HDPE clay nanocomposites prepared with melt mixing demonstrate increased stiffness and strength with increasing concentrations of clay nanocomposites and adhesion promoters. Taguchi design of experiment (DOE) methodology determined the optimum material conditions to achieve maximum strength and stiffness. The nanocomposites increased tensile modulus and tensile strength, but reduced elongation of LDPE and HDPE. Maleic anhydride and acrylic acid improved the tangent modulus and ultimate tensile strength of polyethylene/clay nanocomposites.
Chain sequence distribution calculations for terpolymers using probability model and Monte Carlo simulation methods are discussed. The SSS, AAA, SAS, SSA, ASA, AAS trial concentration are obtained. Molecular weight and ceiling temperature effects are studied using the Monte Carlo method.
Sejin Han, Franco Costa, Peter Cook, Shishir Ray, May 2002
In this paper, numerical methods to analyze the flow of thermoset materials during the molding process have been developed. A finite-element method is used for the three-dimensional flow analysis. The numerical analysis results have been verified by comparing with experiments. In the experiment, a semiconductor chip encapsulation process using a thermoset-molding compound has been used to observe the melt-front advancement shapes. The calculated and experimental results show good agreement.
84 countries and 60k+ stakeholders strong, SPE
unites
plastics professionals worldwide – helping them succeed and strengthening their skills
through
networking, events, training, and knowledge sharing.
No matter where you work in the plastics industry
value
chain-whether you're a scientist, engineer, technical personnel or a senior executive-nor
what your
background is, education, gender, culture or age-we are here to serve you.
Our members needs are our passion. We work hard so
that we
can ensure that everyone has the tools necessary to meet her or his personal & professional
goals.
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.
This site uses cookies to recognize members so as to provide the benefits of membership. We may also use cookies to understand in general how people use and visit this site. Please indicate your acceptance to the right. Learn More..