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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Currently, only specially treated and compacted carbon fiber recycles can be fed into the twin screw extruder. In this paper, different delivery forms of fibers are characterized in terms of the product quality. The differences between the fibers for twin screw extrusion is illustrated.
The design of an extrusion die has been evaluated utilizing a 3-D polymer extrusion simulation software for optimal flow. The flow pattern, pressure, temperature, and shear rate are simulated in the software. The post-die extrudate shape is also simulated to show the improvement by balancing flow velocity in different sections. The combination of 3-D modeling and simulation decreases the time and difficulties for tuning the die during manufacturing.
Failure analysis and reverse engineering can greatly expedite product development. Infrared and Raman spectroscopy is the among the most powerful tools for this application because each molecule has a unique infrared and Raman signature. Infrared and Raman microscopy was successfully used to identify foreign particles on elastomers and to depth profile multilayer polymer film. Details of the measurement techniques are discussed.
In this study, the welding of several formulations of injection molded agave-fiber filled biocomposites were studied. A 240Hz vibrational welder was used and weld pressure, amplitude, and weld time were varied to determine their effects on lap shear weld strength. Strength testing was performed with a universal testing machine. The morphology of the weld zones was also analyzed to gain insight into the mechanics of the welding.
This study presents the recent development of three-dimensional prediction of cross-linked ethylene propylene diene monomer rubber (EPDM) with chemical blowing agent azodicarbonamide (ADCA) in transfer molding process. Plunger retraction is applied after transfer process is completed. The reaction kinetics model, density model, and viscosity model are applied to describe the complex foamed rubber system in the simulation study. The experimental investigation of material properties into EPDM/ADCA system are studied to make physical parameters in simulation model more realistic. The flow front behavior, the density of foamed rubber, the reaction behavior in foaming and curing conversion are examined to understand the dynamic behavior of the rubber material in both transfer and foaming stages. Furthermore, we study the effect of foaming and plunger retraction. Simulation results show that foaming effect make clamp force larger, however, plunger retraction effect make the back flow occur from cavity to pot to avoid high pressure in the cavity and therefore eliminate the mold clamp force. This study is of great relevance to light weighting application and should reduce the product-to-market cycle time by eliminating the need for the traditional trial-error method.
As designers and engineers continue to push the boundaries of high performance and lightweight design, the use of complex geometries and composite materials is growing. However, traditional composite manufacturing often requires the use of additional tooling and molds which can significantly increase the cost. In this study, a carbon fiber reinforced composite bike saddle is designed and manufactured to demonstrate a newly developed hybrid composite manufacturing process. Using a 3D printed epoxy to print the final part geometry and co-cure pre-impregnated carbon fiber reinforcement, the bike saddle can be optimized, designed and manufactured in less than 24 hours.
Thermoplastics have been blended with reactor-based and grafted-ethylene copolymers for over 50 years to improve room temperature and low temperature ductilityfor many applications, including those in the automotive, appliance, sporting goods industries. The compatibilityof the modifier with the thermoplastic matrix and the rheology of the blend components are key factors in controlling blend morphology. The amount of modifier used and the morphology obtainedaffect the balance of critical properties, including stiffness,impact toughness, and flow. Compatibility of the modifiers with the thermoplastic matrix can be controlled by composition of the modifier produced in-reactor, use of additional compatibilizers (such as diblock copolymers), and by in-situcompatibilization achieved through reactive blending. This paper reviews commercially practiced technologies for impact modification of various thermoplastics based on ethylene copolymers.
In plastic part production, 3D metal printing is a leading manufacturing method for fast, waste-less, and high-accuracy way for making molds with conformal cooling channels. In this automotive power supply test-seat assembly case, the development process combines injection molding simulation, 3D metal printing technology and real experiments to demonstrate an effective mold development approach. Simulation-driven conformal cooling design minimizes the mold temperature difference and significantly reduces part deformation from the traditional straight-line cooling design. Through 6 sets of distance detection, the product dimensions are optimized and can improve the fitting of the three assemblies.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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-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.
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.
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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
Available: www.4spe.org.
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.
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