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
The Effect of Aqueous Media on Creep of Recycled Plastics
Jeffrey Exley, Brad Williams, May 2002
There continues to be a need for additional uses of recycled plastics. A significant portion of recycling applications require outdoor exposure including use in aqueous applications. This paper covers the effects of water on the properties of recycled plastics under tensile loads. The paper also covers long term creep effects.
Effect of Cavitation on Product Cost
Justin E. Boyle, Andrew W. Jaglowski, May 2002
In today's industry, there is a constant debate over the methods used to meet production requirements. Using a single, high cavitation tool is often compared against using multiple low cavitation tools. There are numerous factors that must be considered when deciding on which tooling option to specify and its ultimate effect on part cost. The scope of this paper is to serve as an aid in the tool selection process by providing a step-by-step process that allows a company to make a well-informed decision on tooling layouts while considering the impact of each factor on part cost.
Effect of Groove Geometry on the Performance of Grooved Feed Extruders
Christine Ronaghan, John P. Christiano, May 2002
The effect of varying groove geometry on the solids conveying performance of a grooved feed extruder was evaluated. Three groove styles and two resins were evaluated on a single barrier screw design. The results indicate that groove geometry has a strong effect on extruder performance for HDPE but a negligible effect for LLDPE.
Effect of LCP Addition on the Properties of Hybrid Composites
Sreekumar Pisharath, Shing-Chung Wong, May 2002
A hybrid composite consisting of rubber toughened nylon 6,6, glass fiber and LCP was investigated by varying LCP content. The hybrid system exhibited better processability than the glass fiber reinforced composite. A decrease in the total torque was observed with the LCP content indicating the reduction in the energy consumed during the processing of the hybrid composites. Thermal stability of the glass fiber reinforced composites improved with LCP addition. SEM observation of the tensile fracture surface revealed LCP fibrillation in the toughened matrix.
The Effect of Moisture on the Rheological Behavior of Calenderable Copolyesters
Eric J. Moskala, Kab Sik Seo, May 2002
The effect of absorbed moisture on the rheological behavior of a series of calenderable copolyester resins is studied. Moisture has a profound effect on the viscosity of the resins at calendering temperatures and on the glass transition temperature of the resins. However, moisture does not lead to hydrolysis of the copolyesters at the relatively low temperatures used in calendering.
Effect of Runner Design and Gating on Concetricity of High Precision Cylindrical Molded Parts
Richard Wheeler, Kathy Garnavish, May 2002
This paper presents a study on how shear induced melt variations, developed in runners, continue into a cavity and affect the shape of high precision cylindrically molded parts. Melt variations from the runner create asymmetrical conditions within the part forming cavities. These asymmetrical conditions can create side-to-side variations which effect concentricity in high precisions parts such as gears. Effects of process, gating locations and runner designs are presented.
Effect of Strain Rate on PVC Impact Performance
Amiel Sabbagh, May 2002
The impact behavior of poly(vinyl chloride) (PVC) siding formulations containing chlorinated polyethylene (CPE) and acrylic core-shell impact modifiers was evaluated using an instrumented impact tester. The samples were tested at room temperature over a range of testing speeds. Differences in strain rate sensitivity were observed for the various formulations. The differences appear to be a result of both the impact modifiers and the overall formulation.
Effect of Structural Relaxation on Dynamic Mechanical Properties of Poly(Methyl Methacrylate)
B.R. Davis, N. Mekhilef, May 2002
Mechanical spectra of atactic poly(methyl methacrylate) were measured via dynamic mechanical analysis. Measurements were taken on specimens annealed in the temperature range of 23 to 100°C for varying lengths of time. It was found that the effects of thermal treatment are more varied than previously reported, with significant differences found in the breadth and location of the ? and ? relaxation peaks.
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.
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