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
EXPERIMENTAL STUDY OF FIBER-MATRIX SEPARATION AND FIBER DENSITY DISTRIBUTIONS IN FIBER SUSPENSIONS
Christoph Burgstaller, Wolfgang Stadlbauer, May 2010
Defects such as fiber density distributions and matrix separation are commonly encountered when molding polymer composites. Only in the last two decades this problem has been acknowledged by researchers. Such defects are an expensive source of inefficiency that has proved difficult to control and predict. This paper presents results obtained from an experimental setup using pressed samples of silicon oil containing carbon fibers. It is shown that increasing the closing velocity of the mold and the viscosity of the matrix leads to a lower chance of fiber-matrix separation, whereas a growing fiber weight content of the mixture causes a higher chance of separation. It is also shown that there is not only fiber-matrix separation in the flow front but also within the molded charge.
THE INFLUENCE OF MOISTURE CONTENT ON THE MECHANICAL PROPERTIES OF WOOD AND NATURAL FIBER REINFORCED COMPOSITES
Christoph Burgstaller , Wolfgang Stadlbauer, May 2010
The aim of this work was to investigate the influence of absorbed water on the mechanical properties of wood plastic as well as natural fiber reinforced composites. Different composites, with variations in wood content, wood type (and also with flax fibers) and polymer type were produced via twin screw extrusion and injection molding. Mechanical testing (tensile and impact properties) was carried out on samples in the initial state and after certain intervals of water storage. The results are discussed in terms of wood and fiber content and type as well as polymer type, to show the correlation between water uptake and formulation of the composites.
SIMPLE OPTIMIZATION OF PLASTIC PRODUCTS THE DESIGN STAGE
Jan Spoormaker, May 2010
Most designers of plastic products have little education in plastics and have not been trained in calculating plastic parts. The Strength of Materials textbooks derive equations for externally load beams, but many plastic parts, like snap-fit fingers, have prescribed deflections determined by the geometry of mating parts. In snap-fit design tapered beams are beneficial because less material is used and the occurring strain can be reduced up to 30 %. In most textbooks no useful formulas for tapered beam are presented. The threshold for engineering designers to use calculations is rather high and trial and error methods are widely used. Sometimes specialists are consulted to carry out FEM calculations. The problem with these methods is that the designer does not gain insight when others use these methods.
SOLID-STATE SHEAR PULVERIZATION: AN ALTERNATIVE TO NUCLEATING AGENTS FOR SOME SEMI-CRYSTALLINE POLYMERS
Cynthia Pierre , Amanda M. Walker , Katsuyuki Wakabayashi , John M. Torkelson, May 2010
The crystallization kinetics and physical properties of four semi-crystalline polymers polyethylene polypropylene (PP) -polycaprolactone (PCL) and poly(ethylene terephthalate) (PET) were enhanced using solid-state shear pulverization (SSSP) processing without the addition of nucleating agents. Solid-state shear pulverization processing resulted in enhanced isothermal crystallization rates of at least 27% for PP to as much as 85% for low density polyethylene (LDPE). The Youngƒ??s modulus of PCL increased by 65% after pulverization and moderate changes were observed for the other polymers.After SSSP the oxygen permeability of LDPE decreased by 17% PCL by 30% and PET by 55%. Changes in the shape and size of the spherulites during crystallization are attributed as the basis for the enhancements of the physical properties of the polymers.
SOLID-STATE SHEAR PULVERIZATION: AN ALTERNATIVE TO NUCLEATING AGENTS FOR SOME SEMI-CRYSTALLINE POLYMERS
Cynthia Pierre , Amanda M. Walker , Katsuyuki Wakabayashi , John M. Torkelson, May 2010
The crystallization kinetics and physical properties of four semi-crystalline polymers, polyethylene, polypropylene (PP), -polycaprolactone (PCL), and poly(ethylene terephthalate) (PET), were enhanced using solid-state shear pulverization (SSSP) processing without the addition of nucleating agents. Solid-state shear pulverization processing resulted in enhanced isothermal crystallization rates of at least 27% for PP to as much as 85% for low density polyethylene (LDPE). The Young’s modulus of PCL increased by 65% after pulverization, and moderate changes were observed for the other polymers. After SSSP, the oxygen permeability of LDPE decreased by 17%, PCL by 30% and PET by 55%. Changes in the shape and size of the spherulites during crystallization are attributed as the basis for the enhancements of the physical properties of the polymers.
A TECHNIQUE COMPARISON FOR THE QUANTIFICATION OF COLOR CONCENTRATE IN A POLYACETAL COMPONENT
Mary Kosarzycki , Lena Klebanov, May 2010
Color concentrates are an important component in many of todayƒ??s thermoplastic applications. When the level of color concentrate varies a small amount from the nominal the result can be a noticeable change in the appearance of the molded part. In this investigation the level of color concentrate present in molded polyacetal parts will be determined and compared using three methodologies. The methods include x-ray spectroscopy gravimetric analysis and ash content. The three methods are compared in regards to the reproducibility of results and the effectiveness of the technique to quantify color concentrate levels.
A TECHNIQUE COMPARISON FOR THE QUANTIFICATION OF COLOR CONCENTRATE IN A POLYACETAL COMPONENT
Mary Kosarzycki , Lena Klebanov, May 2010
Color concentrates are an important component in many of today’s thermoplastic applications. When the level of color concentrate varies a small amount from the nominal, the result can be a noticeable change in the appearance of the molded part. In this investigation, the level of color concentrate present in molded polyacetal parts will be determined and compared using three methodologies. The methods include x-ray spectroscopy, gravimetric analysis and ash content. The three methods are compared in regards to the reproducibility of results and the effectiveness of the technique to quantify color concentrate levels.
INVESTIGATION OF THE CORRELATION BETWEEN THERMO-MECHANICAL PROPERTIES AND PERCOLATION THRESHOLD IN CARBON FILLED POLYPROPYLENE NANOCOMPOSITES
Chun Chu, Kyriaki Kalaitzidou, May 2010
This study aims to investigate possible correlation between thermo-mechanical properties and percolation threshold in carbon filled polypropylene nanocomposites. The goal is to identify an indirect way to determine the percolation threshold without the need to measure the electrical conductivity of a plethora of specimens which is a cumbersome task. The percolation threshold is the basic required feedback of all the existing theoretical models that describe the electrical conductivity of composites materials and are used as design tools. Polypropylene is used as the polymer and exfoliated graphite nanoplatelets, carbon black and vapor grown carbon fibers are used as fillers. Electrical conductivity and rheological properties of PNCs are characterized as a function of fillerƒ??s concentration. The need of accurately determining the percolation threshold is demonstrated by comparing the electrical conductivity data to the predictions of the modified Mamunya model for all three systems studied.
THERMAL CONDUCTIVITY OF POLYMERS FILLED WITH NON-ISOMETRIC FILLERS: A PROCESS DEPENDENT ANISOTROPIC PROPERTY
Christoph Heinle , Zaneta Brocka , Gerrit Hülder , G.W. Ehrenstein , Tim A. Osswald, May 2010
Non-isometric fillers used to raise thermal conductivity of thermoplastics to up to 15 Wm-1K-1 become oriented during the injection molding process bringing new opportunities for thermal management concepts for complete plastic housings. By changing the flow conditions different filler orientation profiles and hence distributions of conductivity values are obtained. A 3- dimensional analytical approach for predicting the thermal conductivities of polymers filled with non-isometric fillers is presented.
THERMAL CONDUCTIVITY OF POLYMERS FILLED WITH NON-ISOMETRIC FILLERS: A PROCESS DEPENDENT, ANISOTROPIC PROPERTY
Christoph Heinle , Zaneta Brocka , Gerrit Hülder , G.W. Ehrenstein , Tim A. Osswald, May 2010
Non-isometric fillers, used to raise thermal conductivity of thermoplastics to up to 15 Wm-1K-1, become oriented during the injection molding process, bringing new opportunities for thermal management concepts for complete plastic housings. By changing the flow conditions, different filler orientation profiles and hence, distributions of conductivity values, are obtained. A 3- dimensional analytical approach for predicting the thermal conductivities of polymers filled with non-isometric fillers is presented.
The Acoustic Behavior Of Thermoplastic Tribological Pairings
Michael O. Kobes , Robert Feulner , Sebastian Krippner , Gerrit Hulder , Tim A. Osswald, May 2010
The acoustic behavior of frictional pairings with plastics is dependent on several factors. Next to the matrix materials, polymer modifications as well as tribological and mechanical additives, such as PTFE and glass or carbon fibers, play an important role. At the Chair of Polymer Technology, research on the triboacoustic properties of various frictional pairings (POM, PA, etc.against POM, PA, 100Cr6, etc.) has been conducted. In addition to the material pairing, the influence of system properties such as sliding speed, and contact pressure on acoustic intensity and frequency spectrum were analyzed. This report shows a triboacoustic system and explains the findings and results of conducted tests, which help the engineer, when designing 'squeal-free' or 'low-squeal' frictional pairings with plastics.
INTERPHASE CHARACTERIZATION OF POLYMER NANOCOMPOSITES
Md A Bhuiyan, Mehdi Karevan, Kyriaki Kalaitzidou, May 2010
The effect of the reinforcement-polymer interphase on the overall performance of the composites becomes more dominant as the size of the reinforcements decreases. The focus of this study is to characterize the interphase of polypropylene nanocomposites. Carbon nanotubes and graphite nanoplatelets are used at concentrations in the range of 0-1 wt%. Nanoindentation, atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used to assess the interphase. The hardness, modulus and topography are measured and the interphase thickness and adhesion between the matrix and nanoparticles are evaluated. Understanding the role of interphase can lead to new design tools for development of advanced polymer nanocomposites.
INVESTIGATION OF THE HEAT HESITATION IN THE IN-MOLD-DECORATION PROCESSING WITH THE FILM
Shia-Chung Chen , Shih-Hsien Tarng , Cheng-Han Tsai , Yan-Chen Chiou , Wen-Hsien Yang, May 2010
In-mold decoration (IMD) becomes a more and more popular process recently due to its high manufacturing efficiency; therefore, it is important to investigate and realize the complicated process mechanism of IMD. In this study, a PC film is attached to the cavity side for observing the heat hesitation effect. This effect will be compared with that in conventional injection molding (without PC film) both experimentally and numerically.Through the comparison between all experimental and simulation results, we can find both experiments and simulation are in a good agreement.
SIMULATION OF TWIN-SHEET BLOW MOLDING TECHNOLOGY FOR AUTOMOTIVE FUEL TANK INDUSTRY
Shreyas Chakravarti, Hongtao Shi, Jos van Gisbergen, Nina Vaze, May 2010
Extrusion blow molding using cylindrical-shaped parisons has been the process of choice for the production of plastic fuel tanks (PFT) for the automotive industry. A revolutionary process called twin-sheet blow molding is now recognized as an innovative technology for manufacturing PFT. BlowView??, a commercial finite element software developed by the National Research Council Canadaƒ??s Industrial Materials Institute, has now been adapted to simulate this new process type. It supports engineers to sketch and visualize PFT designs resulting from the twin-sheet process, before committing to expensive tooling in manufacturing. Optimization to improve quality, decrease cost, etc., is also under investigation.
POLYCARBONATE-POLYESTER BLENDS FOR HIGH FLOW APPLICATIONS
Shreyas Chakravarti , Hongtao Shi , Jos van Gisbergen , Nina Vaze, May 2010
The following paper describes polycarbonate (PC)- polyester blends that can be used for applications demanding high flow while simultaneously having the ability to process at lower temperatures. The presence of a polyester with a lower glass transition temperature that is miscible with the polycarbonate leads to lower processing temperatures and increasing flow while maintaining transparency. To further increase the flow the molecular weights of the polycarbonate and the polyester are reduced. An expected compromise in impact properties is mitigated by the addition of an impact modifier while maintaining transparency.
INCORPORATION OF SILICONES INTIO WOOD USING SUPERCRITICAL CO2
Scott A. Eastman , Alan J. Lesser , Thomas J. McCarthy, May 2010
Wood samples have been impregnated with silicones and subsequently crosslinked in-situ by utilizing supercritical CO2 as a solvent and transport medium.These wood-silicone composites have been exposed to controlled thermo-oxidative conditions under load to determine their time to failure. The time to failure of wood samples has been found to be related to temperature through an Arrhenius type relationship. The addition of silicone to wood significantly increases time to failure suggesting that the silicone is acting as a reinforcing scaffold during the thermal degradation of wood.
INCORPORATION OF SILICONES INTIO WOOD USING SUPERCRITICAL CO2
Scott A. Eastman , Alan J. Lesser , Thomas J. McCarthy, May 2010
Wood samples have been impregnated with silicones and subsequently crosslinked in-situ by utilizing supercritical CO2 as a solvent and transport medium. These wood-silicone composites have been exposed to controlled thermo-oxidative conditions under load to determine their time to failure. The time to failure of wood samples has been found to be related to temperature through an Arrhenius type relationship. The addition of silicone to wood significantly increases time to failure suggesting that the silicone is acting as a reinforcing scaffold during the thermal degradation of wood.
COMPLIMENTARY FAILURE ANALYSIS METHODS AND THEIR APPLICATION TO PLASTIC PIPE
Jennifer M. Hoffman , Maureen T.F. Reitman , Suresh Donthu , Paul Ledwith, May 2010
A variety of methods can be employed to characterize failure modes of plastics and identify contributing factors. By combining visual and microscopic examination with chemical analysis, the reasons for ductile, brittle, or progressive failure may be determined. This paper provides a comparative analysis based on fractography and spectroscopic analysis of chlorinated polyvinyl chloride (CPVC) pipe samples that failed due to chemical exposure. Chemical degradation and environmental stress cracking failure modes are explored using optical microscopy, scanning electron microscopy, and FTIR.
EFFECT OF INCORPORATION OF DEVULCANIZED RUBBER ON THE PROPERTIES OF A VIRGIN TIRE COMPOUND
Rama Konduri, Chris van der Weele, May 2010
In this work, devulcanized rubber obtained from a thermo-mechanical devulcanization process with supercritical carbon dioxide was utilized in a virgin tire compound in order to lower the material cost. Different content of devulcanized rubber from 10 phr to 30 phr was used as part of the rubber in an actual virgin tire compound. Curing characteristics, Mooney viscosity, tensile strength, tear strength, elongation at break, and hardness of different samples were measured in order to evaluate the impact of incorporation of devulcanized rubber in a virgin tire compound. The results show that up to 30 phr devulcanized rubber can be used in a virgin tire compound without any significant deteroriation in compound properties.
PROCESSING AND CHARACTERIZATION OF PEEK/MWNT NANOCOMPOSITES PREPARED BY HIGH POWER ULTRASONIC WAVES
Rishi Kumar, Avraam I. Isayev, Todd Lewis, May 2010
A single screw extruder having ultrasonic barrel attachment was used to manufacture polyetheretherketone (PEEK) - multi walled carbon nanotubes (MWNT) nanocomposites with enhanced dispersion of carbon nanotubes (CNTs) in polymer matrix. The effect of ultrasonic amplitude and CNTs loading on die pressure, electrical conductivity, rheological, morphological and mechanical properties of PEEK filled with 1-10 wt% MWNT was studied. The die pressure was observed to decrease with the increase of ultrasonic amplitude and increased with the increase of CNTs loading. The electrical percolation threshold was found to be between 1 and 2 wt% loading of CNTs.
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