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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Morphology Development in Immiscible Polymer Systems by Bakers Cut
Chaotic mixing produces self-similar mixing structures through repeated stretching and folding of materials interfaces, which can be exploited in processing of polymers to produce morphologies unachievable in conventional single and twin screw extrusion processes. In this study, the self similar mixing process is idealized by baker's cut, whereby materials are affinely stretched and folded or stretched, cut, and stacked. The process is repeated to produce morphology in the blending of immiscible polymer systems of polypropylene (PP) and polystyrene (PS).
Morphology of PMMA/PP/PS Ternary Blend Based on the Interfacial Tension between Their Components
In this work, the morphologies of ternary blends of PMMA/PP/PS with different compositions were studied. Core-shell and separated dispersions morphologies were observed. The morphologies were compared to spreading coefficient and minimal free energy surface theories using interfacial tension data presented here. Excellent agreement between observed and predicted morphologies was found. It was observed that the interfacial tension influenced the number of particles present in the shell phase in the case of core-shell morphology.
Neuro-Fuzzy Quality Recognition in Vibration Welding of Thermoplastics
On a worldwide scale, no commercial or scientific method is available for reliable, non-destructive rating of vibration welds. Industrial production depends on mechanical spot checks and statistical methods. Therefore an innovative quality concept (fundamentals: process knowledge, artificial intelligence) was developed. Since being presented at ANTEC '93 (1), it has been optimized and tested with simple specimen and complex applications. The system now enables reproducible joint strength classification, just by analyzing the vibration welding process.
New Forced Feeding System for Regring Extrusion
For the extrusion of regrind material on Grooved Feed Extruders (GFE) or Smooth Bore Extruders (SBE) it is necessary to increase specific output rate in order to control melt temperature at high screw speed. Instead of using a regrind screw with an adapted channel depth, a new force-feeding system is introduced which fits on the feed opening of the extruder. This system has a grooved fixed mandrel and a rotating hollow shaft containing the screw thread. This new system can act as an addition to an existing extruder. Some experimental results will be shown in the paper as well as the theoretical background.
New Functional Biopolymer Natural Fiber Composites from Agricultural Resources
In this paper we report about a research on innovative exploitation of agricultural resources.Thermoplastic biopolymers such as PLA or MaterBi can be derived from vegetal carbohydrates. Properties of biopolymers are similar to those of commodity resins; to improve their performance they can be compounded with vegetable fibers. Biocomposites are pelletized and injection molded or produced in form of mats suitable for compression molding. Possible applications in automotive field are investigated through the production of car part prototypes.
A New Test Method for Flexural Creep
Creep properties are shown by applying a constant stress to a plastic specimen and measuring the strain as a function of time. The flexural creep of a material is related to temperature and stress effects. This study measures the effect, constant temperature has on creep properties of polycarbonate (PC) while different stresses are applied. Specifically, a heat deflection temperature testing apparatus is used to provide a constant temperature when a fixed amount of pressure is applied to the plastic.
New Thermoplastic Vulcanizates (TPV): Polymers with Elevated Future Prospects
Innovative thermoplastic vulcanizates (TPV) with high oil resistance will be described, consisting of thermoplastic polyurethanes (TPU) as matrix material and a dynamically crosslinked synthetic rubber phase. For the latter one ethylene-vinyl acetate copolymers (EVA) are used. The vulcanization step is realized by means of an organosilane crosslinking concept. For catalysis and water addition, necessary to accelerate hydrolysis- and condensation reaction, new catalyst (?Lewis acids) and water carrier systems are proposed and applied.
Numerical and Experimental Investigation of Three-Dimensional Flow in Microchip Encapsulation
A three-dimensional finite element software is developed to simulate the incompressible, shear-thinning flow of thermosetting polymers coupled with thermal and curing effects. The SUPG method is used for upwind discretization of the energy equation. A control volume scheme with a fixed finite element mesh is employed to predict the fluid front advancement. The numerically predicted fluid front advancement in a microchip encapsulation cavity is compared with the experimental results.
Numerical Simulations on Multi-Layer Co-Extrusion Process
A finite element method was used to simulate the polymeric fluid flow in multi-layer co-extrusion annular dies. New methods were proposed to update interface and node positions in the flow field during the interface updating procedure. The methods can be easily applied to the coextrusion process with no limitation on the extrusion layers. Examples are given to demonstrate the application of the updating methods. Discussions on the problems with finite element selection and path line method application are also presented.
Overview of Ultrasonic Welding - Principles and Applications
Welding of plastic components has been playing a very essential role for system and subsystem integration of subcomponents. Ultrasonic welding process has been one of most popular welding processes for thermoplastic assembly. Effective usage of ultrasonic energy generated by the ultrasonic welding machine has been allowing various types of manufacturing processes such as welding, precision degating of molded parts, staking, seaming, embossing, ultrasonic molding, and so on. The most positive advantage of the process is the highly precise process control with a quick cycle time.
Photodegradation of Poloystyrene
The rate of photo degradation of polystyrene in our society (Tropical Climate) has really limited its applications to mostly indoor use. This led to a wide range of research works on the effect of our Climatic condition on the photo degradation of polystyrene. Through studying and compilation of research findings and industrial informations, the primary causes, effect and factors affecting photo degradable in our society are discussed.
Plastic Laser Welding
This paper reviews the evaluation of simultaneous through transmission infrared welding (STTIr) for joining selected under the hood applications." It was found that applications such as a brake fluid reservoirs could be effectively welded with STTIr without part marking or generation of particulates."
Polymers in Tissue Engineering: Basic Principles, Main Challenges and Characterization Requirements
This keynote lecture discusses the use of biodegradable polymers as tissue engineering scaffolds. The basic principles of tissue engineering are addressed, going from scaffolds processing to some brief information on biological studies. These topics are introduced in a way that an audience composed by plastic engineers can easily became aware of the importance of the field and understands its complexity, as well as the role of biodegradable polymers on its success.
Polyolefin Market Review - 2002
We will present a review of the world and US and Canada" demand for polyethylene and polypropylene from 2000 with a forecast to 2010. We will also look at the relative profitability of producing these resins in 2000. The polyethylene portion will be broken down into grades produced by the conventional high pressure process by the low pressure linear low density grades and high density grades.The paper will be based on 2000 data but the presentation at ANTEC will include some 2001 year end data."
Polypropylene Produced by Binary Supported Catalyst Based on Metallocene
The binary silica supported catalyst system comprising the Cp2ZrCl2 and SiMe2(Ind)2ZrCl2 metallocene compounds was prepared with different immobilization methods and evaluated at different propylene polymerization conditions. The homogeneous isolated catalysts and also the homogeneous catalyst mixture were also employed for comparison. High activities were obtained with the supported systems and the molecular weight of the produced polypropylene was invariably higher than the homogeneous precursor.
Predicting the Heat Seal Performance of Ionomer Films
The heat seal strength of a flexible plastic package depends on the extent of molecular penetration at the seal interface, which in turn is a function of sealing jaw temperature, line speed and film thickness. Thinner films reach the maximum seal strength at lower jaw temperature or faster line speed than thicker films. A model is developed that combines heat transfer with molecular diffusion at the interface. The model points to how laboratory data may be used to predict the sealing performance of ionomers in high-speed packaging lines.
Prediction of Failure and Fracture Mechanisms of Fiber Reinforced Composites Using Finite Element Analysis
A finite element (FE) model is developed to study the stress transfer from matrix to fiber in a short fiber reinforced composite. The critical length of fibers to insure the ultimate stress transfer, is predicted by the model. The interfacial stresses evaluated by FE model are compared with the well known shear lag (SL) and modified shear lag (MSL) models. The competing failure mechanism in short fiber reinforced composites and the triggering stresses for that are recognized.
Prediction of Parison Swell in Extrusion Blow Molding Using Neural Network Method
A neural-network-based model approach is present where the effect of the die temperature and flow rate on the diameter and thickness swells of parison in the continuous extrusion blow molding of HDPE was incorporated. Comparison of the neural network model predictions with experimental data yields very agreement and demonstrates that the network model can predict the parison swells at different processing parameters at a high degree of precision (within 0.001).
The Prep Virtual Factory: A Suite of Processing Simulators
The Plastics Resources for Educators Program (PREP) has produced a vast array of multimedia training materials for plastics educators and the plastics industry. Products completed so far include graphics, animations, and teaching modules. The latest product is a suite of plastics processing simulators called the PREP Virtual Factory." This fully interactive teaching facility includes "machines" for extrusion injection molding and blow molding. Using these tools learners can discover proper operating procedures and investigate the influence of various process parameters on product properties."
Pressure Distribution in Screw Extruders
Pressure in extruders is usually measured only at the end of the extruder barrel (P-barrel) and at the die inlet (P-die). In some extruders multiple pressure transducers are placed along the length of the extruder barrel so that the axial pressure profile can be measured. Such information provides invaluable information about the behavior of the extruder and is extremely useful in troubleshooting extrusion problems. This paper discusses various pressure profiles and explains what they tell us about the processes occurring within the extruder.
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