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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Pressurization and Energy Characteristics of ZSK40 Twin Screw Elements: The Power of Spreadsheet and Good Experiments vs. CFD?
A complete study of pressurization and energy characteristics of various elements of ZSK40 with two grades of PS are presented. This work builds upon previous works [1,2,3] and identifies the differences between screw and kneading blocks and shows by appropriate factors, most of these differences can be displayed by dimensionless curves. The work compares the experimental results with CFD results developed independently by BASF and Krupp Werner & Pfleiderer researchers. In this work, we try to show that the myth created around kneading blocks (wide disc or narrow discs) and their efficient use can be answered by understanding the conveying nature of these elements.
Training Program for Troubleshooting Injection Molded Defects
The objective of this project was to develop a systematic program for teaching plastics technicians and engineers how to enhance their troubleshooting skills for solving injection molded part problems and defects. A prioritized troubleshooting procedure was first developed for 12 of the most common molding defects and their major manifestations. For each defect classification, real life molding scenarios were developed for use as the core of the hands-on practitioner training. Each of the defects had to be generated through a series of molding trials to find a combination of mold, material, and processing conditions that would create a distinct defect and appropriate case study problem for use in the training program. Below are four common defects that yielded positive case studies.
Interactive Training in SPC in Injection Molding
Even though statistical process control, SPC, has been around for over half a century, many injection molding companies still do not use it effectively, if at all. A major barrier to the implementation of SPC is unfamiliarity with basic SPC tools and how to apply those tools to injection molding operations. Successful implementation of SPC requires effective training not only in SPC, but also in injection molding process technology. SPC can identify process problems, but cannot solve them. Operating personnel can only solve process problems effectively if they have a thorough understanding of the injection molding process. Training continues to be a challenge for many injection molding companies. The traditional method of on-the-job-training is often ineffective, time consuming, and frequently results in less than optimum performance. Another option is sending people to off-site seminars. This is costly in terms of travel and registration as well as time away from the job. Recently, a new option for training in extrusion has become available, Computer Based Training, CBT, using interactive, multi-media programs. Interactive CBT offers several advantages, such as: cost effective, self paced, less time away from the job, better understanding and retention of the material, training test results available to training administrator, etc. This paper describes a new training program in statistical process control in injection molding that is delivered on CD-ROMs. The program not only shows slides and video with full narration, it also makes extensive use of 2D and 3D animation to show parts of the injection molding process that cannot be observed on actual machines. For instance, the program shows a detailed animation of flow of the plastic in the plasticating unit, the nozzle, and the mold. The program also shows the reciprocating action of the screw in the plasticating unit and the movement of the check valve at the end of the screw. The program also contains a simulati
The NMR Spectra of Lead Stabilizers
High resolution proton and 13C NMR spectra of lead-based heat stabilizers and their reaction products, obtained using the magic angle spinning technique, support structural assignments inferred from IR spectra. These demonstrate that lead stabilizers are unique compounds, rather than the double salts of lead oxide found in textbooks.
Customer Service for Engineers and Engineering Managers
Engineering is a service. Often in dealing with facts, figures, and information we forget that ours is a customer driven business. We all have customers, internal or outside of our company. There are ways to remind ourselves of our real goal in engineering: Customer Satisfaction with Our Work Product. This presentation will address and present a few of these ways to help us keep our focus on our customers.
Erasure below the Glass Transition Temperature of the Effect of Isothermal Physical Aging in a Fully Cured Epoxy/Amine Thermosetting System
Erasure below the glass transition temperature (Tg) of the effect of isothermal physical aging (at temperature Ta) in a fully cured epoxy/amine thermosetting system is investigated. The results show that physical aging and deaging below Tg account for subtle but measurable changes in moduli over wide ranges of temperature.
Synergistic Flame-Retardance of Polypropylene
In burning of polypropylene, addition of decabromo diphenyl oxide plus antimony trioxide greatly improved oxygen index, but seriously increased smoke density. Addition of hydrated basic magnesium calcium carbonate only improved oxygen index slightly, but dramatically reduced smoke density.
Estimation of Long-Term Properties of Epoxies in Body Fluids
Polymers and adhesives for medical applications require performance data that is normally not found in resin supplier technical sheets. In this example, candidate epoxies were considered for bonding polysulfone lumens together. The effects of saline moisture and temperature on the glass transition temperature of the epoxies were evaluated using Differential Scanning Calorimetry (DSC). Master curves were created using Dynamic Mechanical Analysis (DMA) to predict long-term behavior of the material from short-term testing.
Extrusion Design with the Carreau Model
This paper gives a solution for the steady, fully developed two-dimensional flow in a shallow channel, typical of screw extruders, and specific data for the Carreau and the Ostwald-deWaele model fluids with PMMA as an example. It is concluded that the Carreau model should be given preference over the Ostwald-deWaele model, the latter being the standard in engineering practice. The Ostwald-deWaele model fails to represent viscosities deviating from the power-law region, leading in certain situations to significant errors. The inclusion of the Carreau model does not necessarily introduce added complexity into the analysis.
Toughened Blends of Polystyrene and Ethylene-Styrene Interpolymers
Ethylene-styrene interpolymer (ESI) resins prepared using a constrained geometry catalyst were found to make tough blends with a polystyrene (PS) resin, with the toughening effect dependent upon the relative proportions of ESI and PS resins. At low levels in the blend, an ESI resin forms dispersed micro-domains of sub-micron size in polystyrene. At 40 wt % of styrene, an ESI resin makes a co-continuous blend that is both stiff and ductile. This toughening effect increases as the styrene content in the ESI resin increases, peaking at approximately 70 wt % of styrene.
Selling for the Technical Professional
Highly evolved and complex products often require technical personnel to make sales calls with business development team members. Whereas many Ph.D. holders, managers, and engineers are comfortable talking about procedures and problems, selling products or working smoothly as part of a business development team may be challenging. The paper gives a brief overview of preparation, common techniques and resources to improve effectiveness of the technical professional in sales. This is not a selling course, but a springboard to learn how and where to better sell your expertise outside to customers and inside to colleagues.
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.
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