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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Thermal management of LED (Light Emitting Diode) luminaries is the key to success of LED lighting design. Managing the LED junction temperatures within the prescribed limits ensures the continued light output, improved life expectancy and lower power consumption per unit of light output. LED luminaires require certain performance criteria to be fulfilled while an all-plastic luminaire solution designed from an existing metal design. This includes thermal, mechanical, electrical, & optical aspects of its performance. A design methodology has been developed for the design plastic luminaires to meet thermal performance criteria. Computational methods are used to evaluate the thermal performance of heatsink designs and experimental methods to validate them.
With the advent of efficient and robust numerical analysis techniques such as finite element analysis (FEA) and the increased computing power of today’s hardware solutions, it has become practical to simulate thermo-mechanical behaviors of plastics and rubbers that can capture the physical reality of such materials with high fidelity. Replicating physical behavior of highly complex and non-linear materials such as plastics have positioned FEA tools to create life like models that will behave like the real part or product. Such simulation can compare very well with the physical test. Therefore, using FEA techniques one can perform virtual testing to design plastic products and also can use simulation techniques to optimize design based on a mathematically robust approach instead of heuristic, experience based approach only. Using FEA one can address the needs of the product development lifecycle from concept through detailed design capturing realistic simulation of underlying complex physics.Employing accurate and robust non-linear solver that can handle complex CAD models one can accurately solve mechanical behavior involving very large deformations, contact interactions, complex loads and boundary conditions and material non-linear response such as hyper- and visco-elasticity and material anisotropy.Current presentation discusses the state-of-the-art of numerical techniques and tools including an array of material models that are available to perform realistic simulations of plastics and rubbers. Few relevant examples are described where FEA techniques are used for design and analysis of components made of plastics and rubbers. They include plastic bottles for consumer product goods, medical devices, pump seals, and assemblies made of plastics and metal frames.
Eastman Chemical Company has developed a new copolyester that combines the best of Spectar™ and Tritan™. The material has high heat resistance, strength, and stiffness as well as a number of other desirable characteristics. These include a low coefficient of friction, excellent ultrasonic welding, and great chemical resistance. The material is also excellent for injection molding, reheat stretch blow molding, injection stretch blow molding, extrusion blow molding, and extrusion. In addition, bio-content or recycled content can easily be incorporated. The characteristics of this new polymer enable molding and design freedom in a number of applications with the clean chemistry of copolyesters.
The RingExtruder consists of twelve coaxial screws which are arranged in an annulus. All adjacent screws are closely intermeshing and rotate with identical speed around their own axis. The mechanical agitation is very similar to the co-rotating, closely intermeshing twin screw extruders if only two screws are observed separately. The arrangement of the screws in a circle creates twelve meltpools. This leads to optimal conditions for an intensive axial and crosswise intermixing by mass transfer between the screw channels.The RingExtruder offers outstanding dispersion capabilities together with minimal introduction of mechanical energy. The screws of the RingExtruder have 12 intermeshing zones, which produce a flow pattern with a very high degree of elongation, which can be utilized for highly efficient and energy-saving dispersion. In consequence, improved product quality can be achieved and considerably lower product temperatures are obtained.Furthermore, the geometry of the RingExtruder offers a very high surface-to-volume ratio. Thus, a large heat transfer surface area is available. Special designs of the extruder barrels and the centre core allow for an extremely efficient cooling of the processing unit. Therefore, the RingExtruder allows to control material temperatures within defined limits in order to avoid degradation or the unwanted onset of pre-vulcanisation.Due to the splitting of the product flow into the twelve screw channels an enormous surface of the plasticized material with very small volumes is available. Additionally, the twelve intermeshing areas of the screws ensure a frequent material deflection and thus a high rate of surface renewal. This gives the RingExtruder an outstanding performance in degassing processes.The RingExtruder is used for various tasks in the field of compounding, reactive extrusion and devolatilization. Typical applications include the large-scale recycling of postconsumer PET, the continuous production of rubber compounds, the processing of shear-sensitive and/or highly filled materials as well as the manufacture of adhesives.
Producing consistent, high quality regrind is a key factor in many molding processes. Wittmann-Battenfeld’s screenless granulator technology is designed to process reinforced plastics and enhance your molding process resulting in fewer rejected parts and reduced costs.The new S-Max series of screenless granulators produce uniform, high quality regrind with a minimum of fines and elimination of longs. These low speed, high torque granulators are low in energy consumption, provide durable cutting tools for a longer life and less sharpening maintenance and come in a compact design to accommodate tight spaces. The S-Max series upgraded technology delivers an innovative solution for grinding hard, brittle and fiber glass filled materials.Primary topics:• Screenless granulator technology• Design advantages and application• New product launch: S-Max Series • Upgraded features, options and benefits
Processing resin efficiently is a key factor to yielding a conforming product in any molding process. Energy savings is the focus of Wittmann-Battenfeld’s innovative solution to minimize energy costs while delivering the ideal amount of dried air for your process requirements. Wittmann Battenfeld’s Variable Frequency Drive drying systems with Process Flow Control Technology, has opened the doors to energy savings. Combining both Variable Frequency Drives and Flow Control Valves provides a complete, automatic central drying solution for efficient, redundant, and worry free resin processing. Primary topics (what the registrant will learn):The presentation/discussion will cover following topics:• Variable Frequency Driven Drying system design and benefits• Drying Hopper Flow control design and benefits• VFD and flow control as a redundant system• Dry air conveying system designs and benefits
A new product is patent pending which will allow Medium Area Additive Manufacturing users to be able to 3D print using industry standard pellets of any type. The new TWW Micro (TM) Extruder has be develope to overcome the problem of processing standard size pellets in small extruders that can plasticize throughput rates between 2 to 20 lb./hr. It also allows the user to extruder polymers such as carbon fiber-filled ABS, PP, PLA, PC and etc. This super small extruder which weighs less that 20 pounds will make it possible to extrude any type of resin that is available to the plastics industry at very low throughput rates needed for MAAM applications.
Polyolefin elastomers (POEs) are a class of thermoplastic elastomer (TPE) that can be easily processed. POEs have broad applications from the automobile industry to the footwear industry, but for highly customizable materials the POEs must be altered on the microstructural scale. In this work, a systematic study of how thermal processing affected the ability of ethylene-octene random copolymers to store and dissipate applied strain energy was undertaken. Ethylene-octene copolymers with different degrees of crystallinity were compression molded and slow cooled, quench cooled, or annealed. Copolymer blends were mixed, varying the ratio of high crystallinity copolymer to low crystallinity copolymer. Tensile testing of the cooled samples showed that the crystallinity correlated to the elastic modulus and hysteresis behavior. The higher crystallinity samples exhibited higher hysteresis and higher modulus than the lower crystallinity samples. The blends were immiscible but exhibited physical behavior between the two components. Actuators were built by molding POE bilayers where one layer had higher elastic recovery than the other layer. Stretching and releasing the bilayer resulted in different extents of bending and twisting depending on the applied strain. Microstructural control will allow for the optimal design of elastomeric materials and actuators with anticipated properties.
Micronized rubber powders (MRPs) have shown superior compatibility in TPOs and excellent elastomeric properties. However, it requires efforts to explore the use of MRPs in useful products and a few challenges need to be addressed. In this study, MRP-filled TPEs were compounded at various loading ratios and the effect of sizes of MRPs was investigated. In addition, the surface details of injection molded parts were studied and induction-heated molding were implemented to improve the surface finish for various applications. Finally, multiple conventional plastic processes were explored and injection-molded parts made out of MRP-filled compounds were demonstrated to discover more potential applications.
Cast polyamide 6 is anionically polymerized from ε-caprolactam. Its good properties are mainly caused by the higher molecular weights, compared to standard polyamide 6. Because of sprues and post-processing, a larger amount of scrap is produced. This scrap is typically incinerated without sufficient use of its high quality properties.However, cast polyamide 6 also offers great potential for material recycling, particularly if its high molecular weight can be retained. As cast polyamide decomposes during processing as well, it is necessary to add some additives during compounding. It is the aim of the presented work, to recycle cast polyamide to highly viscous materials. This is done by adding a polyester-modified wax and a carboxylic acid. It can be shown that it is possible to get materials having viscosities of up to two magnitudes higher compared to a typical extrusion polyamide.The high molecular weight of cast polyamide can be maintained or even outperformed. While Young’s modu-lus and tensile strength remain unchanged, the used wax causes some crosslinking of the polyamide and thus also leading to higher impact strength.
Elastomeric polyisoprene rubber nanocomposite foams were prepared via compression molding at different relative foam density 0.4, 0.5, 0.6 and 0.7. Effect of relative foam density on foam morphology and mechanical properties were studied. The results showed that degradation of chemical blowing agent Azodicarbonamide (ADC) and curing of IR compound occurred simultaneously. Light microscopy results showed that increasing foam density from 0.4 to 0.7 gave rise to a decrease in the average cell size from 530µm to 230µm while it led to an increase of cell density from 25 cell/mm3 to 195 cell/mm3. The compression behavior of foams was studied so as to calculate the normalized elastic modulus as a function of the relative density. Several models of cellular materials and polymer composites were used to understand and predict foams’ compression behavior. Results showed that Gibson Ashby model, having pressure parameters, had the best accordance with the experimental data.
Ideal graphene has excellent mechanical, electrical and thermal properties and is therefore potentially suitable as a functional filler in thermoplastics. Laboratory tests have already shown that very low filler contents are sufficient to achieve a significant improvement of the material properties. However, the investigations carried out so far have been based on experiments on the laboratory scale. These results cannot be transferred to an industrial scale. This is mainly due to the changed geometric conditions as well as the different shear energy inputs and residence times. Therefore, the focus of this work is on the influence of manufacturing conditions on the dispersion and the resulting material properties of graphene-based composites, which are produced by the use of a co-rotating twin screw extruder under near-industrial conditions.The results show that the processing of graphene-based composites in industrial scale is possible. Nevertheless, the effect of graphene on the mechanical properties is less pronounced compared to the properties of graphene-based composites that are produced in laboratory scale, due to a low degree of dispersion. The investigations concerning the influence of the machine parameters throughput, speed, screw configuration and the addition position of the graphene on the properties of graphene-based PP composites demonstrate that the mentioned machine parameters have a significant influence on the process parameters specific mechanical energy input (SME), melt temperature and the residence time of the melt in the twin screw extruder. The quality of the graphene dispersion is generally improved by long residence times and high shear energy inputs, which are achieved by low throughputs and high screw rotation speeds or by the use of a screw configuration with a high energy input. However, the differences in the degree of dispersion shown do not lead to significant differences in the mechanical properties of the nanocomposites. It can be concluded that the residence times and SME are not sufficient to achieve an adequate dispersing quality in the melt mixing process using a twin-screw extruder under near-industrial conditions to achieve significant property improvements.
It is known that the properties of thermoplastic polyurethane (TPU) are related to its constituents. Different soft segments, hard segments and chain extenders offer different physical properties. However, very few studies have investigated the effect of the constituents on the properties of TPU foam. In this study, thermoplastic polyurethanes (TPUs) containing different soft segments were synthesized using a pre-polymer method. The samples were foamed, using CO2 as the blowing agent, by one-step batch foaming. The expansion ratio was controlled by varying the foaming temperature (Tf). The role of nucleation agents was also investigated. The shrinkage of the TPU foam was observed by monitoring the foam density. Due to the high diffusivity nature of CO2, significant shrinkage was observed within several hours. In our case, a stable expansion ratio of 4 times was observed.
In the study, PP/PTFE composites with different degree of fibrillation are prepared. Crystallization and rheology behavior are investigated. PTFE is easily deformed into fiber during compounding. The presence of PTFE fiber enhances the kinetics of isothermal crystallization of PP. The second modulus plateau at the low ω and a tan δ peak indicate the existence of a three dimensional networks. Extrusion foaming results show a 2 orders increase in cell density and 10-fold decrease in expansion ratio due to addition of PTFE compared to that of PP. With PTFE nanofiber, open-cell content of the composites is increased.
This study investigated an application of making thermoplastic polyurethane (TPU) foam using Expancel® microspheres  as blowing agent in handrail production at EHC Canada, Inc. The optimized Expancel® content was found and all properties (especially the mechanical properties) of the foamed handrail were tested. The results reveal that the current extrusion processing parameters do not need to be changed for producing the new foamed handrails with Expancel® microspheres. All foamed handrails passed mechanical tests. This foaming of handrail material resulted in 14% reduction in use of that TPU material and a 10% saving in its cost.
In this work, in-situ nanofibrillated PET is used to reinforcing a PP matrix to enhance the final mechanical properties and foam structure quality of an injection molded sample. Although there have been many approaches to reinforce a polymer matrix to increase the melt strength of PP. Long-chain branching, micro- and nano-scale additives and crosslinking approaches each have their own separate drawbacks. However, the use of nanofibrillated composites is a highly efficient and effective method for foam processing. By fibrillating the PET nanofibers (NF) within the PP matrix, fiber breakage from compounding processes can be avoided. To create the PET-NF, PET and PP were first mixed in a twin-screw extruder to disperse the PET as small spherical domains. Afterwards, this blend of spherical PET in PP is melt drawn through a fiber spinning machine to stretch the PET into fibrils with nanoscale diameters and high aspect ratios. As the PET and PP are melt spun together, the nanofibers are well dispersed in the matrix material and ready to be used as a masterbatch. The PET-NF masterbatch is then diluted from 5% to 0.5 and 0.5%, and used in an injection molding (IM) machine. Using foam injection molding (FIM) with mold-opening (MO), foams of various thicknesses and expansion ratios were created with and without the PET. When high-pressure FIM was compared, the foam quality with the PET-NF was higher than the neat PP matrix. The presence of the PET-NF acted as cell nucleating agents which lowered the energy barrier to nucleation by affecting the interfacial energies and inducing local pressure variations. In addition, the PET-NF likely acted as crystal nucleating agents. With use of MO-FIM, the PET-NF showed a three to four magnitude improvement in the cell density. When the flexural properties of the solid and foamed, with and without PET-NF, samples were compared, the PET-NF samples demonstrated higher flexural strength and toughness. Using PET-NF to reinforce the PP matrix increased the both the solid flexural strength and the flexural modulus of the samples by 5 to 10%. However, when HP-FIM is included, the stiffness decreased as toughness increased, which is typical for most foamed samples. Between the foamed PET-NF samples and neat PP, the foamed samples exhibited an increase of up to 40% for both the flexural modulus and strength. When MO-FIM was used, the results showed that the PET-NF increased the flexural modulus between 23 to 46% and the flexural strength between 15 and 25%. This work demonstrated that PET can effectively be fibrillated in a PP matrix. Using injection molding, the PET nanofibers were effective in increasing both the cell density of the final composites. In addition, the PET nanofibers reinforced the PP matrix to increase the flexural strength and modulus.
We researched a novel simulation strategy that predicts bubble growth phenomenon tailored to high-pressure foam injection molding (HP-FIM) processes. This was done via systematic HP-FIM experiments using a visualization technique. The mathematical model that we developed was based on the well-known “cell model”. To improve the model’s robustness and accuracy, we used the Simha-Somcynsky equation of state for the PS/CO2 mixture, which in turn offers an accurate prediction of the initial bubble radius. Moreover, to capture the fluid flow and mass transport behavior during bubble growth, the transport and rheological properties (that is, its diffusion coefficient, surface tension, viscosity, and relaxation time) that were adopted in this work were functions of the temperature, the pressure, and the gas concentration. In this work, instead of solving the cavity temperature and pressure separately, the temperature and pressure profile inside the cavity were respectively simulated using MoldFlow and experimentally obtained. By inputting the initial gas concentration and the transient pressure and temperature profiles, the proposed model could accurately predict the bubble growth profile under different HP-FIM conditions. The proposed model was validated using experimental data obtained from a series of visualized HP-FIM trials. In both cases, qualitative and good quantitative agreements were achieved between the simulated and the measured bubble growth data.
Attached growth bioreactor process provides surface area to support the growth and attachment of bacteria, and thereby a means to biologically remove organics from wastewater. In this work, an open-cellular polyvinylidene fluoride (PVDF) foams consisted of macroporous structures were designed and fabricated to promote the efficiency of existing biofilm carriers for wastewater treatment. A manufacturing approach that integrated compression molding and particulate leaching was employed to fabricate the PVDF foams. Different contents of salt were used as leaching agent to fabricate PVDF foams with macroporous structures of different total protected surface areas. Experimental studies were conducted to elucidate the structure-to-performance relationships of these macroporous PVDF carriers in terms of bacteria-to-carrier interaction and organic removal efficiency.
This paper provides details on the topic of impact management and injury mitigation for playing surfaces, including Football Fields, Soccer Fields, Playgrounds and other playing surfaces both indoors and outdoors and the use of Expanded Polyolefin Particle Foam in their design and construction.The design and construction of sports surfaces plays an important role in playability, performance, injury reduction, and overall impact management and shock mitigation. Expanded Polyolefin Particle foams are being used to fulfill this role. The properties of Expanded Polyolefin Particle Foams allow for designs which take advantage of the isotropic nature of particle (bead) foams, the highly efficient energy management properties, and the ability to manage energy and mitigate impact with a combination of compression, flex and tension. The ability to shape mold the material allows for the most efficient three-dimensional and multi-axis design for energy management. It also allows further performance optimization through changes in geometry and changes in density.This paper will present recent sports surface design innovations and provide case studies vs. competitive technology. Other benefits of Expanded Polyolefin Particle Foam will be presented including 100% recyclability, water-resistance, chemical resistance, long term performance, and the ability to meet the ever increasing rigorous standards for restricted chemicals. This paper will also explore the latest development in the area of soft bead foam technology. New materials beyond the existing Expanded Polypropylene (EPP) such as advanced thermoplastic polyolefins, elastomers, vulcanizates, and polyurethanes are now being used to manufacture expanded particle foam which provide enhanced benefits in the area of energy management and safety. The benefits of these new materials, which include Expanded Thermoplastic Olefins (ETPO), Expanded Thermoplastic Urethanes (ETPU), Expanded Thermoplastic Elastomers (ETPE), Expanded Thermoplastic Vulcanizates (ETPV), and other expanded material blends will also be shown.
The strain hardening behavior of polymers has important roles in processing such as foaming, film formation, and fiber spinning. The most common method to enhance strain hardening is to introduce a long-chain branching structure on the backbone of a linear polymer, but this method is costly and challenging to tailor the behavior. We hypothesized that in situ shrinking fibers can increase the strain hardening of linear polymers, and the degree can be efficiently controlled. In this study, we show that heat-activated shrinking fibers compounded in linear polypropylene enhance strain hardening and foamability. Moreover, changing processing conditions, such as temperature, can amplify the degree of enhancement. Rheological measurements and physical foaming tests are shown to support our hypothesis.
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