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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Light Emitting Polymer Displays
The burgeoning demand for portable devices with high quality, high information content display capability is driving the search for new display technology. Polymer light emitting diode (PLED) technologies offer the prospect to satisfy these demands as well as other display and non-display applications such as solar cells. The current performance for PLED technology will be described together with a wide range of applications and a discussion on the general commercialisation of the technology.
Material Characterization of LDPE Composites Reinforced with Granite Fines
Characterization of LDPE composites reinforced with granite fines demonstrates unique properties. The granite fines were compounded with LDPE powder and injection molded into tensile bars. Granite-filled LDPE had a higher tensile strength, but a lower tangent modulus and elongation than unfilled LDPE. The reduction in tensile strength can be attributed to the large size distribution of particles or agglomeration of particles that were observed in the SEM micrographs and serve as stress concentrators.
Mechanical and Fracture Properties of Nanoclay-Filled Polypropylene
Maleic anhydride modified polypropylene was compounded with commercially available surface modified montmorillonite in an extruder. Re-compounding ensured the removal of visible tactoids from extrudate but TEM and XRD techniques showed non-uniform dispersion of clay platelets. In this study, we investigated the mechanical and fracture properties of nanoclay-filled polypropylene. Tensile strength and stiffness increased steadily with nanoclay content. The J-integral fracture resistance was also attempted on this novel material.
Mechanical Behaviour of Magnetizable Polymers under Dynamical Load
With magnetic particles filled polymers find in-creasing application for example as signal generators in sensor applications. Apart from the magnetic characteristics in particular also the mechanical behaviour determines the application fields of polymer bonded permanent magnets. Polymer bonded permanent magnets are exposed dynamic loads in practice by high accelerations to usually. Investigations in the article confront comparatively the mechanical characteristics of magnetically high-filled polymers during static and dynamic load and show influences of the filler content and humidity up.
Mechanical Properties of Injection Molded CF/LCP in Direction of Thickness
In order to estimate the modulus of the injection molded CF/LCP thin plate, specimen was sliced in thickness direction, and the distribution of modulus in thickness direction was measured with the sliced specimen. As a result, modulus of specimen near the wall and center in direction of thickness were widely different from each other. Moreover, the modulus of sliced specimen was predicted by laminate theory. The predicted modulus was compared with experimental result and they were same tendency with each other in thickness direction.
Mechanical Properties of Two Component Injection Molded Parts
Monosandwich, overmolding and push-pull are special injection molding methods by which parts composed of two different materials can be produced. While the first two techniques yield structures in which the core material is totally encapsulated (monosandwich) or side surrounded (overmolding), the parts obtained via push-pull exhibit multiple oriented layers of the two materials. A comparison of the morphological developments and the flexural and impact properties induced by the three methods is made.
Mechanical Property and Toughening of Epoxy Nanocomposites
High Tg clay-epoxy nanocomposites were prepared and their morphology and fracture mechanisms were characterized using OM, WAXS, SAXS, and TEM. The addition of 3 wt% of CSR particles to clay-epoxy nanocomposite increases the KIC value from 0.53 to 0.81 MPa?m1/2 (a 53% increase) at ambient temperature. It is concluded that CSR addition to nanocomposites is an effective method to improve the fracture toughness of clay-epoxy nanocomposites. The detailed fracture mechanisms responsible for the observed toughening effect in these epoxy nanocomposite systems will be presented.
Melt Temperature Field Measurement and Modelling in Extrusion
Thermal issues in extrusion die flows are addressed. A combination of point and bulk measurements of melt temperature are made using thermocouples, thermocouple meshes, infrared sensors and ultrasonic methods. Data are used to build a thermal map across a 38mm diameter extrusion die used on a single screw extruder. Predictive temperature plots obtained from CFD simulations using commercial software packages are compared to empirical results. The effects of changing extruder variables, including screw speed, and set temperature are described for a low density polyethylene (LDPE).
A Microcellular Model Evaluation for Dynamically Vulcanized EPDM/iPP Blends
The origins of elasticity in thermoplastic vulcanizates have been debated for the past decade. Previous modeling attempts provide numerical solutions that make assessment of constituent concentration and interactions unclear. A microcellular modeling approach is proposed and evaluated herein to describe the steady-state deformation behavior of dynamically vulcanized blends of ethylene-propylene-diene monomer (EPDM) and isotactic polypropylene (iPP). This approach provides an analytic result including terms for composition and cure state.
Microcellular Plastics: Does Microcellular Structure Always Lead to an Improvement in Impact Properties?
Recent data on impact strength of high-density microcellular PVC and microcellular CPET foams is reviewed. It was found that microcellular CPET foams retain a significantly higher percentage of virgin polymer impact strength than do the PVC foams. The gas saturation pressure appears to have no effect on the impact strength of PVC foams, while in CPET foams it has a major effect on the crystallinity of the foams and their impact strength. The impact strength of microcellular foams does not universally increase upon introduction of a microcellular structure.
Micro-Injection Molding of Medical Products: Machine Specification and Process Simulation
Advances in surgical techniques and the drive toward surgeries, which are minimally invasive, has produced a surge in the need and design of small or micro-sized products. Therefore, while considerations regarding the machine, mold design and fabrication, part design, and polymer processing should be used to produce acceptable parts, of any size, one must consider systemic changes in each area when producing smaller parts. In order to take full advantage of the cavity details an optimized system must be defined and the machine must be able to perform.
Micro-Tensile Testing Method and Sample Preparation for Small Samples
Traditional tensile testing methods use relatively large dogbone samples. Recent work at Battelle required testing of weld-line strength in irregularly-shaped polyethylene samples. The small sample dimensions made it impossible to machine dogbones. A method was developed for preparing thin, rectangular samples by microtoming. Samples were approximately 200 micrometers thick, which is much thicker than produced by normal microtoming methods. However, this size was well-suited to tensile testing. Tensile testing of samples with no weld line produced results similar to those quoted by the resin manufacturer.
Mixing and Stabilization Effects on Mechanical Properties of Poly(Vinyl Chloride)/Layered Silicate Nanocomposites
Poly(vinyl chloride) (PVC) nanocomposites were prepared by melt compounding of treated montmorillonite into a plasticized PVC matrix. Experimental results show how notable improvement in the mechanical properties of the PVC nanocomposites are keyed both to reinforcement parameters and to stabilization. The increase in elastic modulus, which would be valuable for extruded profiles, depends on the amount and type of organoclays, plasticizer, and stabilizer contained in the mixture as well as the time and temperature of mixing.
Mixing and Surfactant Degradation in Nanocomposite Preparation
Nanocomposites with different clay dispersions were prepared via in-situ polymerization and melt intercalation, with and without CO2, and the structure was observed by X-ray diffraction (XRD) and transmission electron microscope (TEM). The effects of clay dispersion, concentration and processing conditions on nanocomposite morphology, fire resistance, and thermal stability were studied. The thermal stability of the surfactant and the dispersion of the clay affect the fire resistance of the nanocomposites. Dispersion of the clay also affects the thermal stability of the nanocomposite.
The Modelling of Large Deformations of Pre-Oriented Polyethylene
We have measured the state of molecular orientation in extruded polyethylene sheet using reversion tests. This state gives rise to anisotropy in stress-deformation behaviour. A novel constitutive relation, consisting of an established large deformation, rate dependent model into which is incorporated a preoriented Gaussian network, is used to model this effect. It has been implemented within the finite element package ABAQUS and applied to large extensions of specimens at various angles to the extrusion direction.
Modern Analytical Methods for Solvent Dyes Quality Control
By application of UV-VIS spectroscopy, chromatography and some other analytical techniques new global tests and specifications for major solvent dyes have been created and validated at GE Plastics. One specification currently covers 15 dyestuffs and any number of new dyes can be added.The new testing protocols considerably speed up the QC of incoming raw materials and allow informative feedback to the supplier in case of quality issues.Rapid screening results correlate very well with color/strength data obtained in plastic testing, often making the traditional extrude-mold-test sequence unnecessary
Modified Clay in Polyvinylchloride (PVC)
Modification of two types of Cloisite 30B and Na+ montmorillonite clays is made by its intercalation with polyvinylchloride (PVC) plasticizers, both low molecular and high molecular. Plate like filler particles are generated by compounding the modified clay with PVC. Plasticized PVC sheets without haze can be obtained. Morphology of such composites is evaluated with XRD and the scanning electron microscopy. The PVC nanocomposites were tested for abrasion resistance, E-modulus and flame resistance.
Molecular Orientation in Injection-Blow-Molded Bottles
The molecular orientation at the surface of injection-blow- molded bottles made from poly(ethylene terephthalate) (PET) and high density polyethylene (HDPE) was characterized by means of front-surface reflection infrared spectroscopy. For PET, the analysis was based on a method developed previously (1), while for HDPE a new approach was developed based on the C-H stretching band at 2915 cm-1 . Results obtained for two different bottle shapes and different injection mold temperatures are interpreted in terms of the process conditions.
More Understanding of CAE
Flow simulation is one of the most important CAE tools used in concurrent engineering for injection molding process. However, it is not a panacea. Users need to understand its capability limitation and use it in a correct way before it can become a useful and powerful tool. In this paper, a two and half dimensional flow simulation (three dimensional temperature analysis and two dimensional pressure analysis) is focused. A few insides regarding modeling, numerical method, molding dynamics, material property modeling, and heat transfer effects will be discussed. This understanding can help us analyze simulation results and make an engineering decision wisely.
Morphological Influences on Density and Deformation of Ethylene-Propylene Copolymers
Density and deformation of ethylene-propylene copolymers are investigated in terms of composition and morphology. The morphology, crystallization kinetics and basic mechanical behavior are examined as a function of sample age in a previous study (1). Initial density appears to be dictated by composition and not crystallinity while changes in density are due to hexagonal crystal formation. Ductility is dependent on branching density and appears to be controlled by selective strain-induced crystallization.
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