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.
Chemical attack of a polymer can occur through
several mechanisms including oxidation molecular
degradation and hydrolysis to name a few. Any one of
these mechanisms can then be accelerated though service
conditions of elevated temperature and mechanical stress
over time (1). One particular failure which occurred for a
glass-filled polypropylene part involved the synergistic
effects of several factors including service conditions of
chemical exposure at elevated temperature while under
mechanical stress. Material issues of part design and resinfiller
interaction were also identified as potential
contributing factors. This paper will summarize the
testing involved in determining the mode and potential
source of the part failure.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Kim McLoughlin Senior Research Engineer, Global Materials Science Braskem
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Kim drives technology programs at Braskem to develop advanced polyolefins with improved recyclability and sustainability. As Principal Investigator on a REMADE-funded collaboration, Kim leads a diverse industry-academic team that is developing a process to recycle elastomers as secondary feedstock. Kim has a PhD in Chemical Engineering from Cornell. She is an inventor on more than 25 patents and applications for novel polyolefin technologies. Kim is on the Board of Directors of SPE’s Thermoplastic Materials & Foams Division, where she has served as Education Chair and Councilor.
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Gamini has a BS and PhD from Purdue University in Materials Engineering and Sustainability. He joined Penn State as a Post Doctorate Scholar in 2020 prior to his professorship appointment. He works closely with PA plastics manufacturers to implement sustainability programs in their plants.
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Tom Giovannetti holds a Degree in Mechanical Engineering from The University of Tulsa and for the last 26 years has worked for Chevron Phillips Chemical Company. Tom started his plastics career by designing various injection molded products for the chemical industry including explosion proof plugs and receptacles, panel boards and detonation arrestors for 24 inch pipelines. Tom also holds a patent for design of a polyphenylene sulfide sleeve in a nylon coolant cross-over of an air intake manifold and is a Certified Plastic Technologist through the Society of Plastic Engineers. Tom serves on the Oklahoma Section Board as Councilor, is also the past president of the local Oklahoma SPE Section, and as well serves on the SPE Injection Molding Division board.
Joseph Lawrence, Ph.D. Senior Director and Research Professor University of Toledo
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Dr. Joseph Lawrence is a Research Professor and Senior Director of the Polymer Institute and the Center for Materials and Sensor Characterization at the University of Toledo. He is a Chemical Engineer by training and after working in the process industry, he has been engaged in polymers and composites research for 18+ years. In the Polymer Institute he leads research on renewably sourced polymers, plastics recycling, and additive manufacturing. He is also the lead investigator of the Polyesters and Barrier Materials Research Consortium funded by industry. Dr. Lawrence has advised 20 graduate students, mentored 8 staff scientists and several undergraduate students. He is a peer reviewer in several journals, has authored 30+ peer-reviewed publications and serves on the board of the Injection Molding Division of SPE.
Matt Hammernik Northeast Account Manager Hasco America
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Matt Hammernik serves as Hasco America’s Northeast Area Account Manager covering the states Michigan, Ohio, Indiana, and Kentucky. He started with Hasco America at the beginning of March 2022. Matt started in the Injection Mold Industry roughly 10 years ago as an estimator quoting injection mold base steel, components and machining. He advanced into outside sales and has been serving molders, mold builders and mold makers for about 7 years.
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How to reference articles from the SPE Library:
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, ISBN: 123-0-1234567-8-9, pp. 000-000.
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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.
