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
Advanced Simulation Methods for Prediction of Multi-Layer Non-Matching Fiber-Mat Applications In Resin Transfer Molding Process
Fred Yang, May 2020
The objective of this study is to use a simulation tool of resin transfer molding (RTM) process to get a comprehensive understanding of the permeabiliy measuring process. In order to varify the simulation tool’s capibility to simulate oil flow in non-matching fabric we build the mesh model of the measuring instrument cavity with the non-matching meshes in this study. This varifaciton case focuses on two properties of the RTM process, the arriving time and local pressure increasing trend in filling process. By using the simulation tools, we can observe the resin flow within the mold. The comparison between simulation and experiment result shows the reliability of simulation result. We expect that this study will help to clarify relevant issues and then reduce the trial-and-error time and materials.
Advanced Thermpolastic Material Solutions To Improve Fuel Economy and Emissions Performance
Rodrigo Orozco, May 2020
Fuel economy and emission regulations are challenging automotive manufacturers to meet global targets, which are becoming more stringent over time, in particular, for internal combustion engine powered vehicles. Internal combustion engines will likely remain dominant for a long time and will require system innovations or in many cases electrification solutions to meet the regulations. This document describes the thermoplastic material solutions to meet the application functional requirements of engine solutions, such as turbocharging, exhaust gas recirculation and gasoline direct injection that are the current trend for system innovations of light-duty vehicles.
Ageing Effects On Two-Component Injection Molded Thermoplastic Elastomers On Polyamide-12
Anna-Maria Persson, May 2020
The effect of ageing on the adhesion between thermoplastic elastomer materials and glass fiber reinforced polyamide-12 materials was evaluated. Test specimens were made by two-component injection molding, and the melt temperatures and the glass fiber fraction were varied. Adhesion before and after ageing was assessed via peel tests. Ageing (11 weeks at 70 °C with 62% relative humidity) severely reduced the adhesion strength. This could be explained by broken covalent bonds and/or disentanglement in the interphase. The individual materials were not severely affected by the ageing.
An Investigation of the Crystallinity in Vibration Assisted Injection Molded Poly-Lactic Acid
Peng Gao, May 2020
Vibration assisted injection molding (VAIM) is a process in which a controlled oscillatory movement is introduced to the injection screw during injection molding. This research was focused on the effect of processing parameters on crystallinity and the crystal structures of poly-lactic acid (PLA) during VAIM. It was observed that vibration assisted injection molded PLA products have higher crystallinity than conventionally molded PLA products under similar conditions. Additionally, the cycle time for fabricating PLA parts can be reduced utilizing VAIM without significant loss of crystallinity. The growth of α´ phase of PLA during VAIM and conventional injection molding process was investigated utilizing an X-Ray diffraction technique. A slight phase change from α´ to α phase can be observed in VAIM samples fabricated under certain conditions. The mean size of crystal structures decreased as VAIM frequency increased to 30Hz.
Analysis of Contributive Forces In Intra-Laminar Shear of Continuous Fiber Reinforced Thermoplastics
Tobias Mattner, May 2020
Continuous fiber reinforced plastics offer excellent weight-specific properties, but their broad introduction to lightweight construction applications is still limited, among other things, due to insufficient accuracy of their processing simulations. A major reason for this is the limited availability of reliable material data and models. In this study, picture frame tests coupled with microscopic analysis are employed to separate the contributions of static weave deformation, lubricated rotational roving friction and roving compression and associated matrix relocation to the total intra-laminar shear forces. This approach allows for additional material insight and helps in developing suitable material models in an efficient way.
Analysis of the Advantageous Process and Mixing Behaviour of Wave-Dispersion Screws in SSE
Marius Dörner, May 2020
In the plastics processing industry, the improvement of the economic efficiency of extrusion lines is important. This is achieved, especially in single-screw extrusion, by an increased throughput at a constant machine size. In order to guarantee high melt quality, new screw concepts are being developed in addition to conventional screws. These include wave-dispersion screws, which are designed to break up the solid bed at an early stage so that the melting and homogeneity behavior is optimized. This paper deals with the experimental comparison of two wave-dispersion screws with a common barrier and 3-section screw. The maximum achievable throughput and in particular the melt quality with regard to thermal and material homogeneity are investigated in order to detect possible advantages of the screw concepts. Here it has been shown that both better thermal and material homogeneity with simultaneously higher possible throughputs can be achieved by wave-dispersion screws.
Analytical Characterization of Commercial Foams for Consumer Bedding Applications
Praveen Boopalachandran, May 2020
The objective of this study was to characterize popular commercial bed-in-a-box mattress and visco topper foams, which are the benchmark bedding products in the market. These products were advertised as gel infused foams that offer superior thermal conductivity and support. Multiple techniques were utilized to identify the composition of the foams. In summary, the commercial “green” and “gray” bedding polyurethane (PU) foams were similar in composition, and they were made of glycerin-initiated PO/EO based polyols. It also showed the incorporation of styrene-acrylonitrile (SAN) in the polymer backbone. The isocyanate part was consistent with an aromatic isocyanate identified as methylene diphenyl diisocyanate (MDI). In addition, the blue gel polymers that were infused to these foams were polyurethane based material. Furthermore, the black particle in the “gray” foam that was advertised as heating wicking material was graphite-based additive.
Analyzing the Machine-specific Process Behavior for Automated Adaption of Setting Parameters
Pascal Bibow, May 2020
As injection molding represents a highly automated, but to the same extend complex manufacturing process to produce e.g. plastic parts without the necessity of post-processing, many efforts focus on compensating fluctuations and reproducing part quality. Injection molding simulation therefore offers the opportunity to determine a valid operating point even before start of production. However, the machine-specific process behavior and the individual machine setup limit transferability of simulated process parameters. Standardized interfaces like OPC-UA for continuous communication with the injection molding machine offer plenty of data from the running production process. Machine data about e.g. screw movements thereby reflect the real-time machine behavior. By analyzing the injection phase at varying injection flow, dosing volume and nozzle temperature with respect to the resulting part weight and the melt cushion, a machine-specific transmission behavior has been observed to adjust settings on different machines based on OPC-UA data.
Antioxidant Activity Effect of Isosorbide into Flexible Polyurethane Foams
Gwangseok Song, May 2020
Isosorbide alkylene oxide (ISB-AO) was obtained by reacted with isosorbide and alkylene oxide, a non-toxic bio-based bicyclic diol composed of two fused defurans to increase the reactivity of isosorbide. A flexible polyurethane foam was prepared using isosorbide alkylene oxide based isocyanate prepolymer (IAISO) consisting of a reaction of isosorbide alkylene oxide and isocyanate. FPUFs containing various types of IAISO have been successfully manufactured without significant degradation of the appearance and physical properties of the final foam. IAISO based FPUF also showed better antioxidant activity by preventing discoloration. Thus, IAISO using bio-based diols with improved reactivity can be valuable raw materials (or additives) born from environmentally friendly FPUFs without seriously compromising the physical properties of these FPUFs.
Application of Hybrid Modeling In Polymer Processing
Christian Marschik, May 2020
For many decades, the setup and solution of polymer processing models involved use of analytical or numerical methods. These characteristics have changed with the recent digitization of polymer processes and the collection of enormous amounts of data. It is increasingly common to use data-driven modeling techniques to analyze processes, for which analytical and numerical models may not fully describe the process behavior in operational situations. These techniques have significantly extended the set of tools available to the engineer, providing new possibilities of how to develop more accurate process models. As a result, the setup of an appropriate modeling strategy more than ever requires a thorough understanding of the individual modeling techniques. This article was designed to address the potentials and limits of analytical, numerical, and data-based modeling techniques when modeling polymer processes. Moreover, we show how these methods can be combined into one hybrid approach to solve polymer process models not solvable so far. The findings are further illustrated by means of a particular use case, which models the flow of polymer melts in single-screw extruders.
Bio-renewable Polyester/Graphene Nanocomposites
Muhammad Iqbal, May 2020
Bio-based polyesters are a new class of materials that are expected to replace their fossil-based homologues in the near future. In this study, nanocomposites of bio-renewable poly(ethylene 2,5-furandicarboxylate) (PEF) are reported with thermally reduced graphene (TRG) via melt blending method and compared with fossil-based PET/TRG nanocomposites. TRG was prepared from graphite oxide by simultaneous thermal exfoliation and reduction method and characterized. TRG was dispersed in PEF and PET via melt blending, and the nanocomposites were characterized for their thermal and morphological properties. The TRG exhibited strong interactions with PEF, increasing onset of thermal degradation by ~50°C and thermal degradation temperature by ~17°C. A strong nucleation was observed in both PEF and PET with the inclusion of TRG.
Bottle-to-Bottle Recyclability for Barrier Packaging Enabled by Surface Modified HDPE
Zhenshuo Liu, May 2020
Ellen McArthur Foundation’s bold vision for The New Plastics Economy is one where plastic goods can be recycled and reused in a closed loop, a “Circular Economy”. A key hurdle to enabling closed loop recycling is the deterioration of polymer properties due to raw material contamination in the recycle stream. Mixed polymer systems, i.e. co-extrusion/multilayer packaging, use barrier materials such as EVOH or Nylon, creating significant issues during recycling. In contrast, having monolayer packaging enables the highest recyclability. Fluorinated HDPE enables monolayer barrier packaging solutions. To further understand its impact on recyclability, Inhance Technologies investigated the inclusion of fluorinated HDPE in the regular HDPE stream. Fluorinated HDPE and regular HDPE were blended at different ratios, re-extruded and pelletized. Following pelletization, bottles were molded from the regrind blends and their properties were evaluated. At all blend ratios, thermal-mechanical properties, chemical fingerprint, and sortability match those of virgin HDPE. The results demonstrate that fluorinated HDPE can be recycled as regular HDPE within the existing recycling infrastructure.
Characterization and Processing of Thermally Conducting Thermoplastic Elastomers For A Microclimate
Szetong de Cleir, May 2020
A commercially available grade of thermally conducting TPE was characterized and processed into tubing for use in a microclimate cooling system. This paper details the material characterization, extrusion of the resin into tubing, and the evaluation of tubing properties. A series of extrusion trials was conducted to establish a relationship between processing parameters. It shows there is a weak relationship between draw ratio and tensile properties. At last, future work is proposed to further improve the thermal conductivity of this material.
Characterization of Impact Toughness of Thin Plastic Films
Sanjib Biswas, May 2020
We investigate the role of film/dart friction on the results of dart impact test used to characterize toughness of plastic films against impact (biaxial loading) at a high speed (~3 m/s). Utilizing an instrumented dart impact (IDI) capability, impact tests were conducted for plastic films exhibiting a wide range of dart impact values under standard conditions. Steel and PTFE dart heads were used with the former representing a high-friction interaction and the latter a low-friction one at the film/dart interface. Our results indicate that differentiation between films on the basis of their measured impact toughness may change dramatically depending on friction. Load-displacement curves obtained from the IDI tests, a simplistic analysis of forces, failed samples, finite element simulations, and high-speed tensile tests help us rationalize our findings about the effect of friction on measured impact toughness of films.
Characterization of Polycarbonate – Using Thermogravemetric-Rheology Analysis
Jamal Al Sadi, May 2020
The objective of this work is to study the rheological characteristic of the formulations and the processing of plastic production. In this work, introduced two polycarbonate resins were melt blended using two different twin-screw extruders, targeted to investigate the PC blends on the characterization behavior of the grade. Formulation and processing parameters showed an excellent effect on controlling the viscosity. The research aims to identify the underlying science by conducting a systematic study of two stages. First, the polycarbonate 30/70% (Grade-3) was chosen from historical data mining extracted in our project as was showing a high number of adjustment; the material was melt-blended using (Coperion) a Co-rotating twin-screw extruder (SB). The two polycarbonate resins (PC1/PC2) were PC1 content (30wt%-pph) of MFI (25gm/10mins) and PC2 content (70 wt.%-pph) of MFI (6.5gm/10mins). The grades also included four different color pigments and three additives. The second stage, the same material was included the same composition were blended in steps of eleven in a Thermo Haake Mini Lab II twin-screw micro compounder (ML). The steps (%PC1/%PC2) were (100%/0%), (90%/10%), (80%, 20%)… (0%/100%). This resulted in eleven batches. The rheological behavior of the compositions with pigment (WP), without pigments and additive (WOP) at 280 0C have been characterized through experimental measurements. The viscosity measurements of Variation PC blends of (30-70%) and at (0%, 30%, and 100%) were characterized at certain processing of (SB) and (ML). Thermogravimetric analysis (TGA) was performed under the effect of heating rate, Glass transition temperature (Tg) for PCs blends was measured and related it is affected by the minute variation blends, viscosities, and the various interactions indicated a significant effect on color changes.
Characterization of the Non-Uniform Compression Behavior and the Internal Morphology in Flexible Polyurethane Foams Using Digital Image Correlation and X-Ray Micro-Tomography
Hieu Truong McElroy, May 2020
In this work, digital image correlation was performed during compression testing of twodifferent flexible polyurethane foams to obtain full-field strain maps and understand the non-uniformdeformation the foams exhibit. In addition, X-ray micro-tomographywas performed on the foam samples at different locations through the thickness to obtain micro-tomographs of the foams’ microstructures. Measurements and statistical analysis from these micro-tomographs made it possible to quantify the cell size distribution and their variation through the thickness, as well as identify differences in the microstructures of different foams.It was found that observations from compression tests with digital image correlation are in good agreement with observations from X-ray micro-tomography analysis.
Chemical Resistance Testing of Polycarbonates and Blends With Hospital Disinfectants and Cleaners
Paul Nowatzki, May 2020
We tested an array of hospital surface disinfectants and cleaners for compatibility with several polycarbonate-based thermoplastic materials commonly used in healthcare equipment. To assess compatibility, we exposed tensile specimens to cleaners while under flexural strain, and then checked for cracking and tensile property retention. The results illustrate which cleaners are the harshest and which materials are the most chemically resistant. We also observed that periodic wiping and drying is frequently more damaging than the traditional test method of continuous wet exposure.
Circular Economy - New Styrenic Polymer Processing Concepts
Cassie Bradley, May 2020
Circular economy is a term describing a sustainable way to interact with all major stakeholders of the economic sphere. One basic idea is to minimize waste creation and to use post consumer waste as raw material for new products. This concept stands in contrast to the “linear economy”, based on products that end in landfill. Circular economy will play a particularly important role for all materials and goods having a short and mid-term lifetime and will have an implication on how these products are designed and recycled. Plastics food packaging are examples for goods, providing safety, protection and extended shelf-life and hence allow us to lead our modern life style. They typically have a short-term lifetime and are disposed after use. Within the challenge of “Circular Economy” however, producers of packaging, as well as upstream raw material producers are requested to provide new concepts for re-use in a true circular way, hence re-cycling rather than down-cycling or waste dumping in landfills. Plastics producers, and especially producers of Styrene-based plastics are taking up the challenge and started to “connect the dots” between municipalities, new recycling technology providers, raw material producers and customers. By promoting “chemical recycling” they are pursuing new ways to create high quality, even food grade plastics based on post consumer waste as new raw material.
Comparison of Fiber Orientation Results of a Moldflow®-implemented pARD-RSC Model to µCT Scans
Sandra Saad, May 2020
Fiber-reinforced polymers have gained popularity in various industries over the past years, as they allow the reduction of products' structural weight without compromising on performance. The material and mechanical properties of such polymer composites are mainly dependent on those of the fibers included in the polymer matrix. It is therefore crucial to be able to predict the fiber orientation in the injection-molded part during the design process. Simulation techniques offer an efficient and cost-friendly way to perform such predictions early on in the development process. However, accurate simulative predictions necessitate precise material models. Therefore, in this work, the prediction accuracy of three fiber orientation models are compared to experimental fiber orientation data obtained from high-resolution x-ray micro-computed tomography (µCT) scans for two different geometries. The models used to describe the fiber orientation in the Moldflow® simulation are a Solver API-implemented pARD-RSC model with shear-fitted parameters, an MRD model with Moldflow® default parameters and an RSC model with Moldflow® default parameters. Through the performed comparison, it was found that today’s state-of-the-art models are still unable to predict the fiber orientation for variant flow regimes and different part geometries accurately. This shortcoming was mainly highlighted for elongational flows.
Compounding Technology (Techniques and Tips) For Improved Performance and Productivity of Automotive
Paul Andersen, May 2020
Ever since the first polymer applications were incorporated into the automobile in the 1960’s, OEM requirements for polyolefin based automotive compounds have pushed the performance envelope with respect to, for example, improved mechanical properties such as flex modulus, tensile strength, and heat distortion temperature; aesthetic properties such as surface quality; processing characteristics such as viscosity; and as always, cost. However, density was not a critical concern since the part being replaced was most probably made of metal. To attain required physical, esthetic and viscosity properties such as those listed above, compound formulations have become very complex. The main additives to the base polymer in early automotive applications such as a battery tray, were typically glass fiber and/or mineral filler for reinforcement. However, as manufacturers have continued to push vehicle weight reduction, they are re-evaluating specifications for current polymer-based applications/parts, i.e. bumpers, trim, etc., for future model years. In most instances, all the specified mechanical and flow properties remain the same, but density is reduced between 5 and 10%. Generally, this requires an extensive material reformulation to meet the new specifications. As part of most light-weighting reformulations, high bulk density filler content is decreased and replaced with multiple grades of polypropylene having a wide range of viscosities. These resins need to be melted and uniformly blended to provide, for example, strength from a high MW, high crystallinity component and good flow characteristics from a low MW grade. Additionally, any IM (impact modifier) needs to be dispersed and uniformly distributed. For reinforcement to be effective, fibers need to be unbundled as well as maintain a critical length during the compounding process. Minerals, depending on their structure, need to be distributed and/or distributed and dispersed. The co-rotating twin-screw compounder has long been the equipment of choice for such compounding functions. However, compounders still face processing challenges such as how to optimize the extruder set up to uniformly compound 1) diverse viscosity matrix polymers, 2) incorporate and disperse impact modifier, 3) unbundle and distribute fibers, and/or 4) feed, distribute and disperse a poor flowing, “sticky” mineral filler or possibly an easy to fluidize low bulk density talc while simultaneously maintaining an economically viable production rate. Additionally, the process can be challenged to maximize fiber length in high viscosity mineral filled formulations. This paper will review requirements for compounding automotive polyolefin compounds with an emphasis on recent innovations in Co-rotating Twin-screw technology that have enhanced product quality and productivity for these complex lightweighting material formulations.
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