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
Web Based Engineering Education
In an effort to develop better teaching approaches for engineering courses, academia is taking a look at alternative styles that implement advanced educational tools as an alternative to lecture-based courses. As the World Wide Web matures, multimedia and programming technologies are evolving to enable the development of instructional software containing significant depth and interactivity. This paper discusses the development and integration of web-based tools to support engineering courses.
Stretch Blow Molding Curriculum Development: Understanding PET-E Bottle Making from a Materials Viewpoint
Addition of Stretch Blow-Molding capability to the Plastics and Polymer Engineering Technology Program at Pennsylvania College of Technology is described. Through a grant from the National Science Foundation, process and analysis equipment was purchased to enhance courses in blow molding, process survey, and advanced processing courses. Copies of laboratory experiences are available nationally on a web site or through correspondence with the author.
Future Directions for Plastics Engineering Education: Technical, Business, and Human Concerns
Engineering practice in the plastics industry typically requires knowledge of materials science, mechanical design, and manufacturing processes. However, the traditional academic focus on these technical fundamentals may not be sufficient to satisfy recent trends in industry practice. This paper reflects on the current state of plastics engineering education and proactively suggests changes in the curriculum to address the needs of the global system of the plastics industry through the three domains of technical, business, and human concerns.
Organotin Stabilizers: Global Regulatory Review
There are many ongoing activities taking place in the regulatory arena regarding organotin stabilizers used in PVC. This paper will provide an overview of the activities, including who is involved and what the issues are. It will also describe how the stabilizer industry is dealing with these issues as part of their ongoing efforts to insure that the use of organotin stabilizers is approved and continues to be safe for people and the environment.
Effect of Extrusion Melt Temperature on Properties of Flexible PVC
This paper provides an insight on the relationship between the physical properties of the profiles extruded from flexible PVC compounds and the extrusion melt temperature. The properties include tear resistance, tensile properties, brittleness temperature and compression set. The effect of heat history on surface characteristics of the extrudate, such as surface roughness and gloss, and their relationship with the processing morphology is also discussed.
Characterization of Bimodal Impact Strength Distribution in PVC Using Instrumented Impact Testing
The ductile-to-brittle transition (DBT) is observed for PVC siding samples using an instrumented dart drop impact tester. Large numbers of test specimens from each sample were evaluated for impact strength to establish a clear indication of bimodality. For a particular sample, a DBT temperature determined from this method may be used to determine impact modifier efficiency, or as a robust quality control check for commercial siding producers.
Mechanism of Organotin Stabilization of Poly(Vinyl Chloride). 7. Association of Methyltin Alkyl Thioglycolates with PVC and its Implication in PVC Stabilization
The stabilization and degradation of PVC by methyltin alkyl thioglycolates was investigated by molecular orbital calculations of the most probable reactions responsible for them. Theoretical studies confirmed previously postulated mechanisms based on experimental results.
PVC Process Window as a Function of Lubricant Formulation
Extrusion responses including impact resistance (mean failure energy,MFE) of the extrudate as a function of extrusion conditions and ester lubricant formulation were evaluated. Mathematical models were calculated using experimental design software facilitating prediction of MFE and melt temperature responses for hypothetical extrusion conditions and lubricant packages. Extruder response predictions are then used to define a process window for hypothetical lubricant formulations where two or more extrusion responses must be balanced. Paraffin, ethylene bisstearamide, and ester based systems are compared.
The Stiffness of Ionomers: How It Is Achieved and its Importance to Flexible Packaging Applications
The packaging industry uses ethylene ionomers for their unique balance of properties, such as high stiffness and low heat seal initiation temperature. These properties result from complex interactions between ionic and crystalline phases. We use studies of ionic strength, crystallization kinetics and thermal analysis to show how these phases form. This new understanding explains how stiffness develops in ionomers and its role in optimizing flexible packaging performance.
Barrier Needs: At the Core of an Innovative Package Development Process
WHY A PACKAGE???CONTAINMENT MARKETING PROTECTION
Computer Simulation of the Film Blowing Process Incorporating Crystallization & Viscoelastic Effects
A detailed two-dimensional simulation of the film blowing process is developed based on a mathematical model that incorporates the Phan-Thien Tanner (PTT) and Neo-Hookean constitutive equation with crystallization effects. The PTT constitutive equation is employed in the hot region, while the Neo-Hookean constitutive equation is used in the cold region to describe the rheological behaviour of the film. The model predicts bubble shape dimensions, temperature distribution, crystallinity, and orientation.
Effect of Polymer Processing Conditions on Shrinkability of LDPE and LLDPE Films, and on Optical Properties of LLDPE Films
The influence of the die gap (DG), the blow up ratio (BUR) and the frost line height (FLH) over shrinkability of LDPE and LLDPE films, and on the optical properties of LLDPE was evaluated using a 23 full factorial plan. For LDPE and LLDPE, shrink decreases in the extrusion direction and increases in the transverse direction when BUR increases. The die gap and the frost line height do not affect the shrinkability of LLDPE. Regarding LLDPE films optical properties, the haze decreases and the gloss increases when both, the FLH and the BUR, decrease.
A Novel Refractometric Study on the Bulk Polymerization of Methyl Methacrylate
On line refractive index measurement for the determination of conversion ratio in the course of PMMA bulk polymerization was developed using He-Ne laser beam with CCD camera. The Snell’s law was applied to interpret the refraction pattern in CCD camera to calculate the refractive index. It is shown that refractive indexes of MMA/PMMA mixtures vary linearly with conversion ratio in bulk polymerization. Mathematical correlation was developed to fit the experimental data.
In-Line Color Monitoring during Polyethylene Extrusion: Reflectance Spectra and Images
Two methods of monitoring the color of pigmented polyethylene during extrusion are being investigated. The first method utilizes a fiber-optic assisted charge-coupled-device (CCD) spectrometer to measure the color of the polymer melt. Highly precise L*a*b* values can be calculated from the reflectance spectra. The second method employs a CCD camera and RGB values are obtained for each pixel in the image of the extrudate. These RGB values track color changes but are sensitive to lighting.
A Dielectric Slit Die for In-Line Monitoring of Polymer Compounding
The dielectric slit die is a new in-line instrument that is designed as a multipurpose sensing device to measure dielectric, rheological, and optical properties during extrusion. The instrument is mounted at the exit of an extruder and consists of a slit with dimensions 2 mm high by 28 mm wide by 15 cm length along which are situated dielectric, pressure and optical sensors. A flexible design permits interchanging of sensor locations and the addition of new sensors.
Monitoring Polymer/Clay Nanocomposites Compounding Using a Dielectric Slit Die
A new in-line process monitoring instrument, a dielectric slit die, was used to examine the compounding of polymer/clay nanocomposites. The instrument is a multipurpose sensing device for measuring dielectric, rheological, and optical properties during extrusion compounding. We report results of compounding nylon 12 and polyethylene ethyl vinyl acetate copolymer with organo modified clays.
In-Line Measurement of Melt Density in Polymer Extrusion Using Shear Ultrasound Waves
Ultrasound shear waves propagating at a frequency of 2.25 MHz is used to measure the density of polymer melt in real-time during extrusion process. The acoustic impedance of the polymer melt is calculated using the measured reflection coefficient of the ultrasound waves off the polymer melt interface. The ultrasound measurement is independent of the attenuation in the polymer melt, which makes this technique highly desirable for heavily loaded polymers and large extrusion dies.
Warpage Index Based on Cooling and Orientational Effects
Sensitivity of different plastic materials to warpage is a common problem for mold designers. Developing a scaled index to allow for better design depending on the material selection would be beneficial to the plastics industry. This study focuses on warpage caused by non-uniform cooling and flow induced stresses on a diverse selection of thermoplastic materials. The effects of fillers and thicknesses will give a broadened range of warpage sensitivity. The index will create a simplified method of material selection and mold design for optimal products.
Ultra High Shear Rates and Their Effect on the Physical and Melt Properties of an Injection Molded Parts
The purpose of this experiment is to determine how ultrahigh shear rates affect the physical and melt properties of polystyrene and polypropylene injection molded parts. Three different runner inserts will be utilized to accomplish this. These three inserts vary the duration and overall shear rate undergone by plastic during the injection process. Data will be collected from tensile and melt flow tests to determine the effects of ultra high shear rates and shear times on the injection molded parts.
Design and Material Issues Affecting Jetting during Injection Molding
This paper presents a study that evaluates the effect of gate and runner designs on jetting, which develops during injection molding. Additionally, the study looks at the sensitivity of various materials to jetting and the material characteristics that affect their tendency to jet. This data is compiled in a table where the materials are ranked on a scale of jettability that will allow mold designers and CAE analysts to use as a frame of reference. Jettability will be more predictable, and many processing problems will be avoided through this research.
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