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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Barrier Properties of Thermoplastic Polyurethane Film for Bladders and Other Containment Applications
Gas transport properties of various thermoplastic Polyurethane (TPU) films are presented as a function of gauge, temperature and humidity. Influence of the TPU's chemical constitution on the transport characteristics is discussed. Empirical data for the different gases and comparison to other soft elastic polymers permit rules of thumb for the selection of appropriate TPU grades for various applications.
In-Mold Labeling for High-Speed, Thin Wall Injection Molding
In-mold labeling [IML] is a process where pre-printed labels are inserted into a mold prior to the introduction of the plastic. This process removes the need for post-printing, which simplifies part handling. By adapting current technology, a simple and robust IML system was prototyped for a four-cavity mold. This paper discusses some of the design issues considered in the development of this particular IML system.
Grafting Extrusion of Low Density Polyethylenes
The grafting of low density polyethylenes with diethylmaleate was carried out in a twin screw extruder. A lower grafting degree was found in the material that showed a higher viscosity in the element of the extruder just below the feed port. The weight-average molecular weight of the grafted materials slightly decreased. However, the Newtonian viscosity and the storage modulus increased when compared to virgin resins. Those facts indicate that chain scission processes are taking place simultaneously with long-chain branching formation.
The Effect of Injection Molding on the Load-Carrying Ability of Products with Holes
Holes may have a considerable influence on the loadability of injection molded products. Both the stress concentration and the effect of processing are important factors. The present research project investigates the combined influence of stress concentration, weld line and local distribution of molecular orientation on injection molded polystyrene plates with a molded-in hole. It is concluded, that the loadability is dominated by the peak stress position at the hole, especially in combination with a low melt temperature during injection molding.
Non-Isothermal Effects in Injection Molding of Rigid Fiber Suspensions
This paper describes a fully three-dimensional transient finite element method for calculating the flow behavior and fiber orientation during filling of injection molded parts. The material anisotropy behavior is modeled by using the Doi-Doraiswamy-Metzner model. Numerical results, involving the filling of a rectangular plate and a test specimen part, emphasizing the importance of non isothermal flow and the three-dimensional coupling calculations between the flow and orientation, are presented.
Melt Rheology and Processability of Conventional and Metallocene Polyethylenes
The melt rheology and film processing behaviours of conventional high pressure-LDPE and LLDPE are compared with both linear and long chain branched (LCB) metallocene polyethylenes. The effects of molecular structure on melt behaviours of these different types of polymers will be discussed in terms of an improved melt strength measurement. Two new parameters: ?(MS)/?P the melt strength pressure derivative and ?(MS)/?(log?), the melt strength shear rate derivative, have been defined.
Value-Added Internal Audits
To get the most value from your internal audit process it must be carried out in a way so as to ensure its continued ability to determine the effectiveness of the overall quality system. The quality system will always undergo change. Even as it matures, change is inevitable as a result of continuous improvement, company growth, restructuring, etc. For that reason, the internal audit process must also be a living system - consistently updated and molded to perform as the tool needed to judge the quality system effectively. It will also then meet the intention of the ISO 9001/9002 requirement of audits... scheduled on the basis of status and importance..."."
Infrared Characterization of Vinyl Cinnamate Copolymer Blends before and after UV Exposure
During the past three years or so we have been studying chain connectivity and its effect on the free energy of mixing and phase behavior of (co)polymer blends. Infrared spectroscopy has been our primary tool because in carefully chosen mixtures it is possible to measure the fraction of hydrogen bonded groups present as a function of composition and temperature. We have now turned our attention to the effect of cross-linking one or both of the (co)polymers in the blend and present the results of recent FTIR spectroscopic studies.
A Bulk Modulus Model for an Epoxy + Glass Fiber Composite as a Function of Pressure and Temperature
Temperature and pressure-dependent volumetric changes of the 8552/S2 epoxy + glass fiber composite were investigated by a Pressure-Volume-Temperature (PVT) technique. The Hartmann equation of state was used to develop a model for prediction of the bulk modulus as a function of both pressure and temperature. This model describes the experimental data very well over a wide range of temperatures and pressures.
Molecular Analysis of Polymers by FTIR Photoacoustic Spectroscopy
FTIR Photoacoustic Spectroscopy (PAS) has advantages relative to conventional infrared techniques (transmission, reflection, and emission) because it is non-destructive, does not involve sample preparation, and can probe samples with compositional gradients and layers. The theory, instrumentation, methods, and applications of FTIR-PAS are discussed and results are presented on several polymer analyses based on FTIR-PAS.
Study of PVC/Grafted Polyethylene Blends
Two commercial types of polyvinyl chloride with different K values were blended with LLDPE, HDPE, LDPE, and their grafted products with diethylmaleate. The PVC/PE blends were prepared in two proportions. The blends made with the grafted LLDPE showed to be more translucent than those prepared with non-functionalized LLDPE, due to a much better interfusion between the particles for the first ones. However, the mechanical properties are lower than those of pure PVC.
Product Design with High Value Recyclable Plastic Waste Streams
As part of on-going studies on the manufacturing of re-engineered materials from waste plastic streams, rheological, mechanical and thermal characterization of recyclable plastics from old computer housings and used carpet materials were carried out, with anticipated use in thin-walled products. A combined stress and mold cavity flow analysis has been used to obtain optimum design and process parameters for the anticipated products.
Case Study for Multi-Shot
The objective of this paper is to demonstrate different manufacturing methods to produce the same or a very similar Multi-Shot part. It will conclude by giving cost breakdowns on all options, including capital cost, cycle time and ultimately piece part cost.
A Web-Based Knowledge Management System for the Injection Molding Process
This paper presents the motivation, development, and system components of a Web-based Knowledge Management System (KMS) for the injection molding process. It also discusses the impact and potential benefits of employing Web technology to manage and share data, information, knowledge*, and analysis results by various parties that are involved in the design and manufacture of injection-molded parts.
A Knowledge-Based System with Fuzzy Logic for the Tuning of Injection Moulding Machines
The proposed system aims at a) helping injection moulders to tune the process parameters of an injection moulding machine, b) storing knowledge and experience that can be used later and c) creating an integrated tool with information on materials, process parameters so it etc. The system is based on general guidelines coupled together with expert rules from the users and a fuzzy logic system which is responsible for the intelligent communication with the users. Results show the way the system operates in an industrial environment.
Investigation of the Rheological Properties of Rotomolding Resins
There are many influential factors and processing variables that can impact the mechanical and aesthetic properties of a rotomolded part. One of the main variables is the resin being processed and its associated rheological properties. The manner by which the polymer powder sinters and fuses together needs to be understood to ensure the correct processing cycle is used to obtain an optimum cured part. The influence of bubbles that form during the sintering phase and the melt index of the material, contribute to the quality of the part being produced.
Analysis, Synthesis and Design of Plastics Processing Operations
In an attempt to prepare our students better for the challenges after their University study, the Departments of Chemical and Mechanical Engineering at the University of New Brunswick are continuously seeking new ways to expose the students to state-of-the-art real world technologies. The authors present an approach for introducing the students to various aspects of plastics processing and training on an example of their senior design course.
Attending Trade Shows: Maximize the Value, Minimize the Hassle
The trade show is a vital component to the plastics industry. As we depend more and more on e-mail, the internet and conference calls, we have become removed from each other. The opportunities to speak face to face, and business to business with so many companies under one roof, is unique to the trade show setting. In this presentation several suggestions and tips" will be discussed which will help you optimize your trade show experience."
Art to Part: A Successful Plastic Product Introduction
A thermoplastic rifle stock for a new rifle was developed. Initial wooden models were shaped to meet market demands. CAD models were produced both manually and using digitizing with little difference in outcome. CAD models should include manufacturing process related geometry issues such as draft allowance and gate vestige size and location. Examples of methods to prevent problems are outlined throughout the development process. Ultimately, a successful new product was delivered to the marketplace with both prototype and production tooling.
A New Hypothesis to Describe the Acting Mechanisms in a Welded Joint of Semi-Crystalline Thermoplastics
Since it is known that cross-linked Polyethylene can be welded, it is clear that the acting mechanisms in the interior of a welded joint are not adequately explained yet. There are several criterion, hypotheses and models that try to describe what happens in a welded joint. In this paper two new promising hypotheses, the Mixed Crystal Hypothesis and the Nexus Hypothesis, are introduced. The Mixed Crystal Hypothesis can be proven by the help of several different examination methods. Other examinations support the Nexus Hypothesis.
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