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.
Polyvinylchloride (PVC) is the most commonly used thermoplastic resin for electrical cable coatings. PVC that hardens after polymerization is not suitable for insulating and protecting wires and cables. The necessary mechanical, thermal, and electrical levels can only be reached with the addition of softeners, stabilizers, and fillers. Composition of the good and the bad PVC samples were analyzed using FTIR spectroscopy and TG analysis. It was found that ditridecyl phthalate was used as a softener in both samples. Magnesium oxide was used as a filler in one sample. The higher amount of water that present in the sample at room temperature and evolves during the first stage of PVC decomposition might be responsible for the low heat resistance of one sample.
This research work addresses the feasibility of employing thermoplastic composites as the substitute material for bipolar plates in a fuel cell. Bipolar plates are vital components of a proton exchange membrane (PEM) fuel cell assembly. Vigorous efforts are directed by manufacturers to reduce the size, weight, and cost of the bipolar plates. The carbon-based composites are comparatively cheaper, lightweight, and can easily be used for the production of bipolar plates. However, the bipolar plate material's electrical conductivity should be sufficient to conduct the electric current from one cell to another. The main purpose of this research was to study the effects of carbon content on the electrical conductivity of the composite material. The composite materials were produced by adding graphite particles into polypropylene matrix at different contents ranging from 60wt% to 84wt%. The through-plane electrical conductivity tests were carried out. While the electrical conductivity of the composites increased by increasing the graphite content. A sudden rise in electrical conductivity was also observed between 76wt% and 80wt%.
Sample preparation for polymer testing is an overlooked portion of the test plan and execution. Thermoplastics and thermoset materials offer multiple methods to prepare samples: injection molding, CNC machining, waterjet cutting, die-cutting, and laser cutting are all used often. We test samples of a polycarbonate (PC) material in uniaxial tension and compare results for injection molded, machined, waterjet cut, and diecut samples. All but the diecut samples showed the same stress vs. strain response, though the waterjet samples failed at a significantly lower strain. The die-cut samples showed significant damage on the edge of the specimens, and had a lower yield stress. Careful selection of specimen preparation methods is important to a well-designed test plan.
Carbon blacks can offer improved performance over dyes in fiber and textile applications in polyester, polyamide and polypropylene resins. Their stringent cleanliness and superior filterability are of critical importance for successful fine denier fiber applications. In this study, the filterability of Birla Carbon’s fiber black Raven 1300 Ultra was evaluated after compounded in PET resin via twin-screw extrusion and a Farrel continuous mixer (FCM). The carbon black demonstrates excellent filterability performance via twin-screw extrusion and an FCM compounding processes. FCM was explored to make atypical PET masterbatches with higher carbon back loadings beyond 30%. However, a further study focusing on improving dispersion and filterability of highly loaded PET masterbatches is warranted to better serve the fiber application.
Inovia Materials LLC is positioned to develop new generation flame retardants and flow enhancers based on ionic liquids, to replace and expand the applications of traditional additives with high “green chemistry” qualities, superior performance and enhanced properties. we have developed new flow enhancers for PC, TPU, TPAE and high-performance plastics: PAR, PPA, PPS, PSU, PEI, PEEK, etc. Our flowing enhancers have superior thermal stability (400 degree C TGA), perfect compatibility (ionic liquids being tailorable), significant increase melt flow index at very low loading level, and mild effects on the physical-mechanical properties of plastics. We welcome product application opportunities from industries.
A complex piece of sporting equipment was molded to customer satisfaction, meeting critical dimensions despite complicated tooling and the use of a crystalline resin. Combining modern simulation techniques and industry expertise proved to be a winning strategy in solving this challenge. The use of post-molding, warp controlling fixtures was completely eliminated from the legacy production process, leading to improved part performance and plant efficiency.
This study compared the longevity performance of polypropylene (PP) and polyethylene (PE) based thermoplastic polyolefin (TPO) waterproofing membranes. It was demonstrated that PE-TPO outperformed PP-TPO for both heat aging and standard UV aging in terms of tensile property retention, weight retention and resistance of surface cracking. Better longevity for PE-TPO is attributed to the lack of tertiary carbon which is intrinsic to PP and prone to chain scission.
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.
Mesh interface and immersed boundary models are presented as simplifications for the simulative design of dynamic mixing elements for single screw extruders. These simplifications have great potential to cut complexity and cost in both drafting and computation. Results for distributive mixing are compared quantitatively and qualitatively to a non-simplified 3D model. It is found that good agreement with the 3D model is achieved when the simplified models’ throughputs are adjusted for mass conservation.
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.
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ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
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