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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The Use of Zinc-Neutralized Ethylene-Methacrylic Acid Copolymer Ionomers as Blend Compatibilizers for Nylon 6 and Low-Density Polyethylene
The effect of composition on the morphologies and properties of uncompatibilized and compatibilized blends of nylon 6 and LDPE were studied over a wide range of weight fractions. The mechanical properties of the uncompatibilized blends had reduced tensile and impact strength after mixing, which was almost certainly due to poor interfacial adhesion between the two polymers. It was found that the addition of a zinc-neutralized poly(ethylene-co- methacrylic acid) ionomer as a compatibilizer can improve mechanical properties. Micrographs showed that the ionomer caused a reduction of the dispersed phase size, especially when nylon 6 is the dispersed phase of the blend.
Using a 2(cubed) Full Factorial Plan to Analyze the Effect that the Reaction Temperature, Al/Zr Ratio, and Pre-Contact Time Has on Propylene Polymerization Employing a Metallocene Catalyst
The influence of the reaction temperature (T), the Al/Zr ratio (Al/Zr) and the pre-contact time (t) on propylene polymerization using Et(Ind)2ZrCl2 (rac-( ethylenebis(indenil))zirconium dichloride) as the catalyst, and hexane as the solvent, was evaluated using a 23 full factorial plan. All the evaluated properties were mainly affected by the reaction temperature. The catalytic activity and the xylene solubles increased when T increased. Both the melting and the crystallization temperatures, the crystallinity, and the molecular weight decreased when T was raised.
Using Blow Molding Simulation Software as a Troubleshooting Tool
Currently, after a new blow molded part is designed, the molds are built then modified until a desirable part is produced. This results in higher mold costs and longer time to market. From the industry standpoint, blow molding simulation software could lower mold costs by predicting potential problems before a mold was built. Potentially, companies could test molding scenarios to determine the feasibility of the design without ever cutting steel. A considerable savings in labor and scrap costs could result. The focus of this research was to determine how effective blow molding simulation software would be when used as a troubleshooting tool.
Using Neural Networks to Predict Injection Molded iPP Shrinkage
Shrinkage occurs in all polymers and it is extremely dependent on processing conditions, like holding pressure, holding time, injection speed, mold temperature and melt temperature.The utilization of shrinkage data allows designers to predict the final part dimensions accurately. Numerical prediction of the part shrinkage can be made using simulation packages availables commercially. However, a part shrinkage involves non-linear material behavior and its estimation involves significant simplifications. The neural networks can model highly non-linear systems and predict a part shrinkage effectively.In this study, a neural network architecture was developed to predict the shrinkage of an iPP injection molded part at several process conditions defined through the design of experiments.
Using Recycled Concrete as a Filler in Polyethylene Resins
Adding concrete fillers to base plastic materials can increase mechanical properties such as tensile strength, flexural strength, and hardness. This can be done through the addition of fillers to a virgin and recycled plastic material. By increasing these properties, plastics can be used in applications where they were not previously used.The effects of compounding concrete filler with polyethylene were studied. Two different percentages of the concrete fillers were added to test different properties against a NEAT (nothing extra added to it) sample of both recycled and virgin polyethylene.
Variation of Electrical Properties with Exfoliation Condition in Nanocomposites
Dielectric measurements were made on clay filled nylon and polyethylene-ethyl vinyl acetate (PE-EVA) copolymer nanocomposites during processing by extrusion. Nylon without clay had a small dielectric dispersion while PE-EVA did not. The addition of Na treated clay to the PE-EVA copolymer increased the dielectric constant (relative permittivity) above that of the PE-EVA copolymer but did not increase the conductivity or cause any dispersion. In both PE-EVA and nylon, addition of akyl ammonium chemically treated clays gave substantial increases in dielectric dispersion that are associated with the intercalated or exfoliated state. X-ray diffraction measurements were made on the composites.
Various Plug Assist Materials and Their Effect on the Thermoforming Characteristics of Polymeric Sheet
Plug assist thermoforming is an art which thermoformers have developed through many years of experience. As the industry becomes more competitive and expands into increasingly difficult products, modeling of the process holds the potential to dramatically shorten development time, increase process and materials efficiencies and lead to new market opportunities.This report presents the results of investigating the force-deformation characteristics of a HDPE polymer sheet when formed with different plug assist materials with the aim towards developing modeling parameters. The variables investigated were plug material, plug temperature, plug speed, plug shape, plug surface roughness and polymer sheet thickness and temperature.
Versatile Manufacture of Barrier Materials by Chaotic Mixing
Recent studies have demonstrated that highly multi-layered films can be formed by chaotic mixing and extruded in various shapes. The number of layers prior to breakup and the extent of breakup are controllable so that versatile manufacturing and property optimization are possible. Layer breakup can yield distinct blend morphologies. Where layer breakup is likely, a large number of platelets form that may be associated with attractive barrier properties. Although methods can be applicable to other blends, the relation of oxygen permeability to various morphologies was specifically investigated for extruded films consisting of ethylene vinyl alcohol copolymer, low density polyethylene and maleic anhydride as a compatibilizing agent.
Vibration Control Effect of Epoxy Beam Sandwich Structure Composites Utilizing Shape Memory Poly (Ethylene Terephthalate)-Poly (Ethylene Glycol) Copolymer
Shape memory PET-PEG copolymer was synthesized by coupling polyethyleneglycol (PEG), a soft segment, to polyethyleneterephthalate (PET) that was made from dimethylterephthalate (DMT) and ethyleneglycol (EG). In addition, maleicanhydride, glycerine, or d-sorbitol was used as a cross-linking agent to enhance its shape memory and vibration control. Sandwich structure consisting of PET-PEG copolymer/epoxy composite laminate was prepared from the above copolymer and glass fiber containing epoxy beam. The mechanical properties as well as vibration control effect were compared while varying the kind of cross-linking agents, and their composition.Finally, enhanced vibration control effect was observed with the proper selection of cross-linking agent and the percentage of incorporation, together with the control of temperature range that showed damping effect.
Vibration Welding of Thermoplastic Polyolefins
Thermoplastic Polyolefins have been extensively used in the automotive industry as well as in other applications. The information about using vibration welding to join these materials is limited. Therefore, the main objective of this paper is to perform a design of experiments and to determine the optimal welding conditions for specific thermoplastic polyolefins materials. A three factor (meltdown, pressure and amplitude) two level full factorial design of experiments was performed. The results indicated that the welding time is a strong function of the vibration amplitude and is less sensitive to meltdown and pressure. In addition, the welding strength is not sensitive to the welding parameters. This result was confirmed by hot plate welding of butt joint samples.
Vinyl Foam Technology: Trends / New Developments
Vinyl foam extruded sheet, profile, and pipe products are in growing demand as a replacement for softwood and for non-foamed PVC in many building and construction applications. As a wood replacement, rigid vinyl foam offers good weatherability, chemical resistance, and flame retardancy and it can be saw n, nailed, and screwed. As a maintenance-free product, it is in growing demand in the building industry. Vinyl foam products are considered as a replacement for non-foamed PVC mainly on the basis of economics. This is especially true in the foam -core pipe market, when with weight reductions approaching 40% , a significant cost saving can be realized. The properties and economics of the extruded product depend critically on both the formulation and the processing conditions. This paper focuses on the new trends and technology developments that have taken place and the effect these have had on these three major vinyl foam markets.
Viscoelastic Properties of Nylon 12 and PVDF
We report the time and temperature dependant properties of Nylon 12 and PVDF characterized using linear viscoelastic theory based on the Boltzmann superposition principle. Dynamic mechanical properties of both polymers were scanned isothermally at intervals of 10°C between 30 to 140°C for five different frequencies, 0.3, 1, 3, 10 and 30 Hertz. Stress relaxation measurements were made using a Zwick tensile test machine between 25°C and 140°C at 10°C intervals using a crosshead speed of 50 mm/min to a maximum strain of 2%. The DMTA and stress relaxation data were compared by converting temperature dependence at constant frequency, into a time dependence at constant temperature. The increase in temperature was converted to a corresponding increase in time using log aT (shift factor) data superposed at 30°C. Good agreement was obtained between the stress relaxation modulus E (t) calculated from the dynamic modulus E`(?) and from that measured experimentally. These results will be used for the prediction of the thermoforming characterisation of multi-layer tubing.
Viscosity Characterization of Bulk Molding Compounds
Viscosity variations in bulk molding compounds have long been a concern. The reactive nature of the polymer, response to thickening agents, high filler and glass loading, all contribute to this variance. Additionally, environmental factors such as storage temperatures and humidity affect the viscosity of these compounds.Confounding the issue is the often forgotten about gage variation. There have been many test methods developed in an attempt to characterize the viscosity of bulk molding compounds. Most of these contribute, as much, if not more to the total variance.This study examines viscosity characterization methods for bulk molding compounds
Viscosity Measurements on Polypropylene Mixed with Supercritical Fluid at High Shear Rates
Viscosity of polymer melts can be effectively reduced by adding constituent of supercritical fluid (SCF) during plastic processing. The viscosity reduction depends on the amount of SCF added and also the magnitude of shear rate. This research modified a conventional injection-molding machine to investigate the rheological behavior of PP/SCF mixture. By measuring the pressure and flow rate of the melt at a slit die which was attached in front of the nozzle, the true viscosity can be obtained after making Bagley and Rabinowitsch corrections. By using this machinery, the shear rate can be achieved as high as order of 1E4 1/s .
A Visual Approach to Better Failure Analysis
Much has been written outside of the technical fields on how to communicate more effectively in groups. The concepts on visually mapping information are directly applicable to conducting a more thorough failure analysis. This is especially true for issues involving cross-functional teams with multiple parties. Studies have concluded that people can process significantly more information visually than they can verbally. A picture is truly worth a thousand words. Cause Mapping is a systems-thinking" approach to visually analyzing documenting communicating and solving complex problems. This presentation will demonstrate an effective approach to failure analysis using a common tool like Microsoft Excel."
Visualisation and Analysis of LDPE Melt Flows in a Coextrusion Geometry
Experiments were performed to enhance our understanding of the interfacial instability phenomena of polyolefin melt flows within a slit coextrusion die. The die configuration allowed a single polymer melt to be used, by using a modular flow cell consisting of a flow splitter, convergent section and die land. The whole of the confluent region and die land are visible through side windows. A further window perpendicular to the flow enables the use of laser sheet lighting for particle imaging techniques. Stress fields in the confluent region and the die land are determined by analysis of birefringence. The die design and experimental techniques allow exploration of the effects of geometry and processing parameters on the source and nature of flow instabilities. Two low density polyethylene melts were studied. Interface instability is observed in the die land for one of the polyethylenes and this results in a 'wave' type distortion of the extrudate. The instability occurs at specific layer thickness ratios.
Visualization of Drop Breakup in Polymer-Polymer Systems
This work studies the deformation and breakup of a single viscoelastic polymer drop inside a viscoelastic polymer matrix using a specially designed transparent Couette apparatus with well-controlled shearing and temperature conditions. Drop deformation and breakup mechanisms were observed through two video camera systems. Polyethylene/polycarbonate (PE/PC) systems over a wide range of viscosity ratios were studied. Two main breakup modes were observed: 1) erosion from the surface of the drop in the form of thin ribbons and streams of droplets and 2) drop elongation and drop breakup along the axis perpendicular to the velocity direction. This is the first time drop breakup mechanism 1) has been visualized in polymer systems.
The Water Injection Technique (WIT) as an Attractive Alternative and Supplement to Gas-Assisted Injection Molding (GAIM)
The water injection technique (WIT), developed at the Institute of Plastics Processing (IKV), Aachen, Germany, is an innovative specialty injection molding process that is closely related to the well-known gas-assisted injection molding (GAIM). The primary aim of the development was to reduce cooling times in the material-saving production of hollow plastics articles by means of using water as a process medium for melt displacement. Besides other advantages, especially the considerably more efficient cooling effect of water meant that cooling times could be reduced by up to 70 % compared with GAIM. Investigations on a wide range of unfilled and filled materials show that WIT constitutes an attractive alternative and supplement to GAIM.
Water Processing Using Polyamide Membrane
Desalination by reverse osmosis and by ion exchange technologies are compared with each other. Now polyamide membrane made from all trans stereoisoner of cyclopentanetetracarboxylic acid chloride by interfacial reaction of m-phenylenediamine, trimeosyl acid chloride A copolymer blend design may be used to prepare a thin film membrane. Turbulent flow keeps the concentration polarization layer thickness low. Composite ion exchange resin is prepared with poly styrene copolymer matrix crosslinked with divinylbenzene with macro reticular structure and weakly basic resins. The macropores in the matrix is filled with acrylic acid copolymer crosslinked with divinyl benzene and weakly acidic groups.
β-Crystalline Polypropylene (Bepol™) and Oriented Film Applications
Polypropylene with high ?-crystalline content is obtained by employing a ?-nucleator, such as ?-quinacridone, N,N’-dicyclohexyl-2,6-naphthalene dicaboxamide or a combination of a Group II metal salt or hydroxide and an organic di-acid compound. In this case, Bepol™, a ?-crystalline polypropylene, contains a small amount of a Group II metal salt or hydroxide and an organic di-acid compound. In this study, various products of Beopl™ have been characterized and applied to oriented film.
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