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

Effect of the Mesh Number Elements in the Simulation Results of Normalized Test Specimens Injection Molded

S. Villarroel, R.A. Morales, A. Sánchez, May 2002

The study was made by modifying the simulation mesh model characteristics to mold normalized test specimens. The simulation results were obtained through a filling/cooling simulation program for the injection molding process. The simulated filling time, optimum cycle time and injection pressure, seemed to be influence by the number of elements model. A best agreement between experimental and simulation results were obtained by increasing the number of elements of the mesh model.

Effect of Wall Slip of Polymer Melts on their Relaxation Modulus Behavior

Dilhan M. Kalyon, Halil Gevgilili, May 2002

The determination of the relaxation modulus using the step imposition of a strain is an important step in the fitting of the parameters of viscoelastic constitutive equation. In the nonlinear region the true shear strain imposed on a polyethylene melt is found to deviate considerably from the targeted strain due to the presence of wall slip which is documented here. The presence of the wall slip reduces the range of strains for which the strain-dependent relaxation modulus can be determined for the linear polyethylene melt investigated.

The Effects of Dynamic Vulcanization on the Morphology and Mechanical Property of Rubber/Plastic Blends

Oansuk Chung, Aubert Y. Coran, May 2002

The effects of dynamic vulcanization on the morphology and mechanical properties of rubber/plastic blends are investigated. This study includes the discussion of why the mechanical properties differ before and after dynamic vulcanization. Enhanced interfacial adhesion by dynamic vulcanization was found to be a major contributor of superior tensile strength of TPV. Rubber elasticity of TPV is a result of the combined effects of crosslinked rubber, morphology, and amorphous PP phase plasticization.

The Effects of Extreme Stress during the Injection Process on Polypropylene

Stephanie L. Bullard, Matthew M. Jackson, May 2002

The strength and viscosity of polypropylene is influenced by extreme stress during the injection process. By varying backpressure of the material in extreme conditions the strength of the part will decrease. Reduced strength of the part will be proven through tensile and impact testing. Numerous material generations of polypropylene will be compared to virgin polypropylene to prove the decrease in strength.

Effects of Lubricants on Processing of Polymer-Wood Composites

Joe B. Williams, Kenn S. Geick, May 2002

A number of lubricants have been evaluated in polymer-wood composites. These lubricants have been evaluated in both HDPE-oak and HDPE-pine composites. Properties measured included extruder torque levels, outputs, extruder shear heating, and visual assessment of extruded part appearance.

The Effects of Machine Nozzle and Sprue Design in Mold Filling Imbalances

Ryan T. Paszkowski, Kathryn E. Garnavish, May 2002

The imbalance between the cavities in a geometrically balanced, multi-cavity mold used for injection molding has previously been explained in theory as shear induced imbalances". (1) The cause of these imbalances can be from uneven shear effects on the melt as it travels to each cavity through the runner. This paper presents a study which finds that the machine nozzle and sprue can have a significant contribution to shear induced mold filling imbalance. The effect of geometry material and process are evaluated."

Effects of Nanocomposites on the Oxygen Barrier Properties of Polyethylene

Shawn D. McConaughy, May 2002

The Permeability of polyethylene limits it's use in applications where oxygen barrier properties are required. Polyethylene, an extremely non-polar molecule, exhibits low permeation levels with polar substances such as water. Conversely, non-polar gasses such as oxygen exhibit high levels of permeation. A silicate nanocomposite was added to reduce the permeation of non-polar gasses while maintaining the low permeation of polar substances. The polyethylene nanocomposite provided better oxygen permeation properties than traditional grades of polyethylene.

Enhanced Impact Modifier for Rigid PVC Formulations

Lawrence J. Effler, Mark T. Berard, May 2002

A new chlorinated polyethylene has been developed for the impact modification of rigid PVC. In addition to imparting excellent impact, the modifier promotes faster PVC fusion, and enhances the formulation's melt strength. Faster fusion allows for economic savings by reducing fusion promoting ingredients and via higher output. The enhanced melt strength results in better part quality, especially for complex profiles.

Enhanced Weatherability of Exterior PVC Building Products - Part II

Charles Crabb, Peggy Schipper, May 2002

Low levels of acrylics are widely used as impact modifiers and processing aids for rigid PVC. At higher levels, acrylics can also significantly improve the long- term weatherability of PVC. Here we report on the ongoing results of a long-term outdoor weathering study of PVC/acrylic blends. Acrylic level, stabilizer type, and weathering location all affected the property retention of the weathered specimens. With proper formulation, the acrylic blends resulted in a significant improvement in the weatherability of the samples versus the PVC controls.

Epoxy Resins from Vegetable Oils

Zoran S. Petrovi?, Wei Zhang, Randy Miller, Ivan Javni, May 2002

Epoxidized soybean oil was cured with citric acid, phthalic anhydride and Lewis acids. Lewis acid initiators and citric acid gave rubbery materials of relatively low strength and low glass transition. Aromatic anhydrides give glassy polymers when equivalent ratio of anhydride to epoxy group is used. Mechanical strength of rubbers is relatively low but that of the glassy materials is typical for plastic materials.

Evaluation of Design and Processing Parameters for Extrusion Blow Mold Pinch-Off Design

Cody D. Greene, Ian S. Laskowitz, John E. McConnell, May 2002

Pinch-off weld line strength is crucial in ext rusion blow molding. This experiment is intended to determine and quantify the processing parameters and design parameters that will produce the strongest weld line strength. Using a 3 level Design of Experiment (DOE) for making the test specimens, the specimens were tested for tensile strength. This data was then used as a guide for producing quality pinch-off weld lines with less guesswork.

Evaluation of Runner Design for Powdered Metal Injection Molding

Michael Bailey, Andrew Schenck, May 2002

It has been observed that a filling imbalance occurs with powdered metal injection molding in multi cavity molds using geometrically balanced runners. This imbalance is typically opposite to the shear induced imbalance developed n these runners with conventional plastic materials The causes and effects of this reversed condition is studied and alternative runner designs evaluated to reduce the imbalance. The alternative designs include the use of the MeltFlipper technology that has proven to solve the imbalance with conventional plastic materials.

Examination of Finite Element Analysis and Experimental Results of Quasi-Statically Loaded Acetal Copolymer Gears

Paul Wyluda, Dan Wolf, May 2002

An elastic-plastic finite element analysis of the quasi-static loading of two acetal copolymer gears in contact is preformed. Load verses rotation of the gear set is compared to actual experimental results. The gear geometry is modeled by plane strain elements with variable thickness between the rim and web. Gear tooth failure is modeled by both deactivating and separating elements when the tensile strength is exceeded. Failure in the tooth root is best modeled by a nonlinear approach using separating elements.

An Experimental Investigation of Screw Configuration on Temperature Rise in Single Screw-Pump Extruders

Gregory A. Campbell, Hongying Cheng, Chicheng Wang, Matthew Bullwinkel, Mary Ann te-Riele, May 2002

The focus of this investigation was to experimentally determine the effect of barrel rotation and screw rotation viscous dissipation inside the screw pump-extruder. The experimental results can be summarized by noting that barrel rotation generated higher temperature rise than screw rotation. Results are presented for seven screw configurations.

An Experimental Study of the Flows in an Energy Transfer Screw

Susan A. Somers, Mark A. Spalding, Joseph Dooley, Kun Sup Hyun, May 2002

A comparison is made between the melting, pumping, and mixing characteristics of a single-screw extruder with an Energy Transfer mixing section and a conventional screw without a mixing section. Results are given for extrusion trials, extrudate sampling, and extrusion solidification experiments performed at different screw speeds and color concentration letdown ratios.

Film Blowing of a Narrow Molecular Weight Polyethylene

Michael A. McLeod, May 2002

Four homopolymer high density polyethylene (HDPE) resins were evaluated for their blown film properties. Film was blown in both conventional linear low density polyethylene (LLDPE) configuration and high molecular weight - high density polyethylene (HMW-HDPE) configuration. Water vapor transmission rates were reduced by nearly 50% in the HMW-HDPE configuration for the narrow molecular weight resins. Haze increased and gloss decreased for the same polymers. The broad molecular weight polymer showed only small changes in these properties.

Film Properties for Good Performance on Vertical Form/Fill/Seal Packaging Machines

Terry A. Clark, John R. Wagner, Jr., May 2002

Technological improvements of flexible form, fill and seal packaging machines are yielding exceptional line speeds, productivity rates and bag features. This paper discusses the evolution of vertical packaging machine development and how it has impacted plastic film properties (e.g. COF, sealing temperature range, hot tack) required for optimal performance.

Fin Assembly in Energy Management

Kal Renganathan Sharma, May 2002

Heat sinking in electronic components in VLSI can be any method by fin assemblies in different configuration. The periodic heating is studied using hyperbolic heat wave propagative equation complex variables. The flux reversal is studied.

Foaming with Microspheres in Rotational Molding

E. Takács, J. Vlachopoulos, C. Rosenbusch, May 2002

A fundamental study of the microcellular foamed structure in rotational molding was conducted by using polymer microspheres as a blowing agent. The influence of the viscosity, temperature dependence of viscosity and first normal difference of different resins on the cell morphology and the tensile properties of the foamed parts was investigated.

Fundamental Characterization of Polypropylene Extrusion

Eric E. Stangland, Joseph Dooley, Mark A. Spalding, EungKyu Kim, Kun Sup Hyun, May 2002

It is known industry wide that polypropylene (PP) resins plasticate in single-screw extruders at rates that are less than those for linear low density polyethylene (LLDPE) resins. The goal of this research is to show the magnitude of this rate reduction, and the physical properties related to processing that are causing the rate reduction.