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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Evaluating Thermal Uniformity with Pulse Cooling
Pulse cooling is a method where mold temperatures are monitored, and cold water is introduced to control the steel temperature. A variation of this technique delivers water immediately after mold closing for variable pulse times. Using this approach, better distribution of surface temperature on injection molded parts may be achieved compared to traditional cooling with a thermolator. Thermocouples and a thermal camera were used to evaluate mold and part surface temperatures respectively.
Impact of Metallizer Process Controls on Optical and Gas Barrier Uniformity
A process study of vacuum metallizer was performed and the results in terms of optical density uniformity, metal adhesion and barrier uniformity were studied. Gas barrier was found to be a complex function of the process parameters studied while adhesion was determined to be sensitive to testing materials as well as process parameters. Visual uniformity was found to depend primarily on metallization pressure.
Effect of Nano-Clay on Foaming of WF/HDPE Composites
This paper investigates the foaming behavior of wood fiber/HDPE composites with small amounts of nano-clay. The nano-clay dispersion was characterized by XRD and TEM. An extrusion foaming experiment blown with N2 was conducted. The cell nucleation and growth of composite foams were studied with varying processing parameters, such as temperature, pressure and clay content. The effect of nano-clay on the final cell morphologies and foam density of wood fiber/clay/HDPE nanocomposite foams were identified.
Strategy for a Selectable Performance Colored Capstock Offering Scheme with Regards to Weatherability and Cost
This presentation will discuss the considerations made when selecting a range of products for use in a Good Better and Best" scheme of weather resistant and cost effective extrudable coating (capstock) offerings. Specifically this paper will discuss creating a consumer offering of varied formulations of materials which provide increasingly better weathering performance with direct trade-offs to cost. As a result the consumer is able to select a specific formulation of material which will satisfy their requirements for performance and budget."
Using Dynamic Mechanical Analyses to Probe the Glassy State Response of a Sub-Tg Annealed Model Epoxy Network
Using dynamic mechanical analyzers the relaxation behavior of a loosely cross-linked model epoxy resin was investigated before and after room temperature aging. Preliminary results indicate a stiffening of the storage moduli occurs below –50 °C, the ? relaxation temperature of the epoxy network, with a subsequent softening of the network above room temperature and a drop in the apparent glass transition temperature (Tg ). of the material with aging.
Study on the Sorption and Desorption of N-Pentane in Polystyrene and Polypropylene
This paper studied the sorption/desorption of n-pentane in polystyrene and polypropylene using the sheet samples. The solubility of n-pentane in PS and PP was measured. And the concentration-dependent diffusivity of n-pentane in PS and PP was computationally modeled. Results exhibit that the simulated profiles match well with the experimental data while the penetrant concentration is above 30%.
Chemical Resistance at Different Stress Levels of Materials with Active Packaging Additives
Active packaging is widely used in the food and beverage industry to help ensure optimum food preservation. Currently, there are differing theories on the effects of active packaging additives on stressed induced plastic parts. This paper presents the results of a study that tests the chemical resistance of several different plastics under differing levels of stress when made with active packaging additives.
The Relationship between Shear Imbalance and Thickness
The effects of shear induced flow variation on the filling patterns of injection molds has been well documented in the recent past. Further understanding of their effects will allow engineers to use these effects to their advantage as opposed to attempting to eliminate their impact. This paper studies how shear induced flow variation is effected by thickness for several materials in a single cavity mold. The results and theories contained herein can be a valuable tool to both a design engineer laying out a new mold and a processing engineer producing parts using an existing mold.
Measurement of PP Melt Swelling Due to CO2 Dissolution
Understanding the thermophysical and thermodynamic properties of polymer/gas mixtures is critical for controlling cellular morphology. This paper describes measurements of pure polypropylene (PP) density and PP/CO2 volume swelling at elevated temperatures and pressures using a newly developed method. Also, measured volume swelling is compared with the swelling calculated from SL and SS EOS.
Impact of Foaming on Electrical Conductivity and Fiber Orientation of COC/Carbon Fiber Composites in Injection Molding
This paper investigates the impact of foaming on the electrical conductivity and fiber orientation of a carbon filled cyclic olefin copolymer in injection molding. Results show that foaming can lead to significant improvement of electrical conductivity in the out-of-plane direction. Due to the preferred in-plane fiber orientation during mold filling, the growth of a bubble adjacent to a carbon fiber would re-orient the fiber in the out-of-plane direction.
Pressure Drop Threshold for Nucleation of PS/CO2 Foaming
Two methods to predict the pressure drop threshold (?Pthreshold) to initiate bubble nucleation in polymer foaming processes are developed. One method uses the modified nucleation theory developed in our previous work, while the other utilizes computer simulations to model the growth profiles of the first observable bubbles in batch foaming experiments. Both approaches have shown good agreement in their ?Pthreshold predictions. Moreover, the effects of pressure drop rate, gas content, and temperature on ?Pthreshold are demonstrated.
A Six-Sigma Approach for Investment Plans in a Plastics Production Plant
It is possible to demonstrate that QFD (Quality Function Deployment) within a norm space permits to realize gap analysis and investment plans for a complex plastics production plant, using its process capability in the last Quality house.For the use of the same metric: DPMO, it is possible to compare man power, materials, maintenance, machinery, environment and methods. In these terms it is feasible to benchmarking the investment plans.
Failure Analysis of a Refrigerator Component Based on DOE" & Optimization Techniques"
There are many engineering situations where it is not necessary to analyze the whole domain of a physical model.In such instances, we demonstrate that it is possible to obtain an equivalent bilinear form using Lax-Milgram theorem with an orthogonal form applied to electrical appliance and turbomachinery, with a transfer matrix and variation principles.This transfer matrix solves a problem in shorter time than the Traditional DOE-FEA (design of Experiments) (Finite Element Analysis) Methods.
Weathering and Light Stabilization of Select Plastic Materials
In this paper we will examine various aspects of weatherability for several significant polymers. Light stabilization and polymer degradation mechanisms will be compared as well as strategies for imparting weatherability for these materials. Several UV aging studies will be included to illustrate stabilization techniques, and some comparative studies highlighting accelerated weathering vs. outdoor weathering will be discussed.
A Study of Integration of LIGA and MEDM Technology on the Micro Injection Molding of Ink Jet Printers' Nozzle Plates
A new approach is introduced to fabricate nozzle plates in this study. The micro mold was made by integration of LIGA and M-EDM technology to improve the accuracy. Micro injection molding was applied to produce the nozzle plates. There are sixty micro through-holes on each plate. The diameters of molded nozzle plates were 102±1 micro meters. The proposed manufacture procedures are believed to be more accurate and economical.
Analysis of Injection Molding to Fabricate Patterned Media with Nano Pillars
We examined a low cost technology for perpendicular magnetic patterned media that uses a metallic nanostamper and injection molding process. In this paper, we focused on the analysis of injection molding with passive heating, where the replication of 50 nm nanopillar arrays was successful. The effect of the thermal insulation layer on the replication quality was examined by analytical and experimental methods. Finally, the properties of magnetic layer deposited on the injection molded nanopillar array were analyzed.
Viscoelastic Behavior of Sulfonated Polystyrene Ionomers
Sulfonated polystyrene ionomers (alkali metal salts) with molecular weight below the entanglement molecular weight of polystyrene were prepared. The rheological behavior of the ionomers was characterized by dynamic and steady-state shear experiments. In general, the viscosity of the ionomers increased with sulfonation level and as the size of the cation decreased. Whereas, the starting polystyrenes were Newtonian fluids, the ionomers were non-Newtonian and viscoelastic.
Visco-Elastic Polyurethane Foams Creep Behavior and Recoverability Analysis
The creep behavior and mechanism of several visco-elastic foams were analyzed in this paper to understand the structure property relationship. The creep behavior and recoverability of these foams were characterized by the compression set, short time creep test, as well as hysteresis with an optical extensometer. The creep mechanism was analyzed and explained based on foam cell structure (cell orientation and uniformity) and material property. Material parameters and cell structure that possibly control the creep and recoverability of visco-elastic foams are also discussed.
On Formulation and Processing of Rigid Polyurethanes via Controlled Cure
A range of polyurethanes (PU) based on methylene diphenyl diisocyanate and polyether polyols varying in molecular mass, backbone structure and functionality are studied. Examination of the kinetic parameters of the PU reactions shows that the curing behavior and the hardness of such complex PU systems do not follow simple mixing rules. Scaling relationships to describe these complex dependencies and basic guidelines for formulation and processing are developed. Limitations of using the OHindex to predict the polyol reactivity are also discussed.
Validation of Injection Molding Simulation Results to Actual Molded Product
The flow patterns and injection pressures predicted using injection molding simulation software and actual flow patterns and injection pressures of the molded parts using a short study were compared and quantified. A method of validation was developed to compare the simulation results with actual molded parts and indicated that by using the correct combination of mesh type and certain process settings in the simulation software, an accurate prediction can be achieved with the simulation.
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