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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Injection Molding and Color: A Basic Look at Design, Processing, & Troubleshooting
The use of color additives in the injection molding process is one of the most effective ways to add value to molded parts. Considerations must be made, however, on how additives are measured, handled, and processed, as well as attention paid to any cross-functional features the final part may require.This paper will examine basic design considerations for adding color at the press vs. using precolored resins in terms of final costs, handling, and processing.
In-Line Compounding: Characterization of Melt Pump Performance
In-Line" compounding is defined as any process in which both the compounding and the forming steps are performed at the same time. For these applications line stability is crucial and greatly affected by equipment selection and design particularly the melt pump. Presented is a performance comparison for the two most common styles of melt pumps: a gear pump and single-screw extruder. Performance will be characterized in terms of pressurization efficiency pressure stability response to system upsets power consumption melt temperature generation residence time distribution and process limitations."
In-Line Measurement of Dispersed Phase Properties Using the Scanning Particle Monitor
The scanning particle monitor (SPM) provides in-line imaging of low concentrations of dispersed phases (e.g. particles, droplets, microgel) at different points across a translucent polymer melt flowing in an extruder. Quantitative measures of size, velocity, and concentration are currently being obtained in polyethylene-based systems. The monitor's ability to scan across a flow channel provides three-dimensional information on the dispersed phase properties. Customization of the system for manufacturing environments is in progress.
In-Line Measurement of Local Residence Time Distribution in a Twin Screw Extruder
A first step towards fundamental optimization of extrusion processes is the determination of the effects of screw elements on flow and mixing. We present a measurement method to study local residence time distribution (RTD) inside a co-rotating twin screw extruder. Using a transfer function, we are able to characterize the effects of different types of elements on the local RTD with a 2-parameter fit. The new approach can be a major step towards determining the correct screw configuration from the desired mixing rate.
Innovation in Extrusion
This paper describes past and recent innovations in extrusion technology. Issues related to implementation of innovation will be discussed with examples of successful as well as unsuccessful implementations. In the end, we will try to look into the future and speculate on possible new developments in extrusion and their effect on the plastics industry.
Innovative Thermoplastic Vulcanizates for Airbag Covers
Driver and passenger safety continues to grow in importance in the automotive industry due to regulatory and market drivers. The increasing demands in airbag technology have challenged the material requirements to extreme levels.This paper describes the development of a new series of Thermoplastic Vulcanizates (TPVs), specially designed for airbag covers. The new materials have proven to be very competitive with other materials in this segment due to its reliable performance in a broad temperature range.
In-Situ Polymerization and Nano-Templating Phenomenon in Nylon Fiber/PMMA Composite Laminates
Supercritical Carbon Dioxide (SC CO2) is used as a reaction/processing medium in the fabrication of fiber reinforced composite materials. SC CO2 allows resin to wet out fiber reinforcement and penetrate inside the fibers themselves. This process produces a composite that exhibits ultra-long range order from the nano-scale to the macro-scale. This paper will discuss the fabrication technique in detail including process parameters and the structure of resulting composites and morphology of modified fibers.
An Introduction to the Theory and Practice of a New Class of Insert Based Rotor Stator Extruder Mixers
Extruders are generally long pipes, which, although an excellent choice for many of its functions, is not ideal for mixing.With a rotor larger in diameter than the extruder to which it is attached our system can deliver excellent distributive and dispersive mixing and the use of mixing inserts allows process conditions to be easily changed.In particular the geometry allows for very high rates of cutting despite very short distances between inlet and outlet.
Investigation into Silinosis Coupling of Polyethylene Polymer Chains
Crosslinked polyethylene is commonly used for hot water applications. The objective of this investigation is to find the optimal loading of an ethanol based silane coupling agent. This will be tested by performing a heated tensile test. This will indicate the polymers crosslink density and modulus. The goal is to find the optimal balance of crosslink density that will yield a pliable final material that can withstand the necessary temperature ranges for hot water applications.
Investigation of Applicability of Two Biodegradable Polymers for Mechanical Applications
Three types of specimens of a polyester-amide and a poly-hydroxybutyrate have been tensile and tensile-impact tested. These specimens represent different geometric characteristics; one specimen has a cold weld line. The influence of injection molding settings on tensile behavior was in agreement with tensile-impact results. Embrittlement was found for all specimen types and both materials after 20 months of storage. The beneficial effect of annealing on toughness was shown for poly-hydroxybutyrate specimens without weld line.
Investigation of Injection Molding Process Robustness for Various Molding Strategies
Several different methods are used throughout the industry to set up the injection phase of the injection molding process. This study is intended to look at the long-term robustness of several methods. Investigating the peak pressure and cycle integral consistency when regrind and check ring wear are introduced will do this.
Investigation of Long-Chain Branching in HDPE Using Triple-Detector GPC
An effective technique for characterizing long-chain branching (LCB) in polyethylene resins has been being developed. Triple detectors (concentration, RI or IR; viscosity, DP; and light scattering, LS) are added to the GPC system to render a powerful capability of studying polyolefin structures. As a result, low levels of LCB in HDPE can be clearly detected. In this work, three model HDPE resins were studied and the level of LCB is found to have a profound effect on the morphology formation in film blowing.
Investigation of Optimum Crystallization Conditions of Polyvinylidene Floride (PVDF)
The purpose of this experiment is to find the time and temperature dependents that yield maximum crystallinity of PVDF as well as its optimum property performance point. We will experiment with a curing temperature range between the glass transition temperature (Tg) and the polymer's melting temperature (Tm) and document the density at set time intervals. We will measure the injection molded article's density to determine the maximum crystallinity because, as the part reaches final crystallization, it will also stop shrinking and will be at its densest state.
Investigation of Stress Cracking and Fatigue Failure in Two-Shot Cavities Using Finite Element Analysis
The purpose of the research was to discover the contributing factors of unexplained cavity cracking in a two-shot molding process. This project used Finite Element Analysis to study the effects of pressure and fatigue stress on the given cavity insert.
Ionomer-Class Nanocomposites with Clay Nanofiller
For compounding experiments, Surlyn types of ionomer extrusion materials were used. Comparison was made between two zinc types of ionomer copolymers with respect to the degree of exfoliation of clay nanofiller characterized by XRD and electron microscopy. Thermomechanical properties were characterized by the temperature dependence of complex modulus on DMA. Abrasion resistance was evaluated as well.
Kevlar®: From Invention to Commercialization
Few recent inventions in fiber technology can be compared with Kevlar® as far as its impact not only on a field of technology but also on the fundamental understanding of relationships between structure and properties of materials. We will attempt to trace it both in processing steps leading to the fiber formation as well as in the properties of the final fiber. This will include placing them in the perspective of science of the time with an expectation to shed some light on the process of invention itself. We will finish the paper by examining how these unique properties are influencing development of applications.
Kinetic Study on PMMA-CO2 System by Raman Spectroscopy
Raman spectroscopy of PMMA was obtained to find out the effect of dissolved CO2 on the phase change of the plastic. It has been demonstrated that the measuring method is useful to evaluate the amount of dissolved CO2 and to recognize the phase change in the polymer induced by the retrograde vitrification.
Knowledge Based Computer Model for Product Mold Cost
Molds used for injection molding are a critical element of part cost. A computer system can be an excellent way to create a mold cost estimation system including components. This paper covers the creation of a knowledge based computer model for production mold cost and demonstrates the most critical factors affecting the overall cost.
Laboratory Tests on Fungal Resistance of Wood Filled Polyethylene Composites
A standard method for determining the durability of structural wood was modified for testing the fungal resistance of composites made from high density polyethylene filled with 50% wood flour. Moisture content, mechanical properties, and weight loss were measured over 12 weeks exposure to brown- and white-rot fungi. Mechanical properties were decreased, but irreversible damage due to water sorption made separating this effect from that of fungal attack difficult. Further modifications to test methodology are suggested.
Latexes of Core-Shell Polymers with High Solid Content Prepared by Microemulsion Polymerization
In this work we present the synthesis of core-shell polymer latexes with high solid content by microemulsion polymerization. The soft core/hard shell and hard core/soft shell structured polymers were obtained by a two-stage emulsion polymerization process using semicontinuous addition of the monomers. The effect on mechanical properties of the ratio of rigid /soft polymer was studied. It was found that as the amount of rigid polymer increases the material becomes stiffer and present a lower elongation at break.
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