SPE Library

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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Conference Proceedings

Cooling Rate Effects on Shrinkage

Andrew E. Resler, May 1999

This paper presents a study on the how cooling rate can produce variations in a plastic materials Pressure - Volume - Temperature (PVT) characteristics which are used in creating shrinkage data for injection molding simulation programs. Most of the currently available PVT data is created using a cooling rate of only 3° C/min. The problem with this data when used to predict shrinkage is that during injection-molding, materials experience much faster cooling rates. This paper presents a study on whether these variations in cooling rates significantly effect the shrinkage values used by mold filling analyses

Effects of Energy Director Geometry and Contamination on Ultrasonic Welds

Roger C. Sager, May 1999

A primary function of ultrasonic welding is to join two or more pieces of plastic together by means of a high frequency sound energy transferred into mechanical energy, thus producing heat adequate to generate a permanent bond. This frequency (20,000 Hz) is focused onto a specific geometric point on the pieces being welded. When properly designed and implemented, the two pieces will form a permanent structure. The geometry of the parts is a critical aspect of the finished product as is the cleanliness of the parts.

Effect of Notch Size" on Falling Impact of PC Sheet"

Jason W. Geiswite, May 1999

How do notch's or grooves in Polycarbonate sheet effect the flexural impact properties of that material? A method was developed to study the effect of notch size" in a falling impact experiment. An apparatus was made to drop a one inch in diameter ball bearing from various heights onto "notched" samples of PC. "Notches" were introduced into the PC sheets by drilling various diameter holes vertically. Results were compared to Notched Izod Impact values of the materials tested."

Synthesis of Epoxy-Clay Nanocomposites

X. Kornmann, H. Lindberg, L.A. Berglund, May 1999

Epoxy-clay nanocomposites have been synthesised by swelling an organo treated clay in a diglycidyl ether of bisphenol A resin (DGEBA) with subsequent polymerisation using different curing agents. The resultant nanostructure was shown to depend on the reactivity of the curing agent but also on the cation exchange capacity of the clay. Characterisation of the different nanostructures was performed by X-ray diffraction and transmission electron microscopy.

Ultrasonic Investigation of Process Variation during Single Screw Extrusion and Injection Moulding: Real Time Detection of Temperature Profile and Material Degradation

E.C. Brown, P. Olley, T.L.D. Collins, P.D. Coates, May 1999

Ultrasound transit time measurements are used on an industrial scale extruder and injection moulding machine to monitor bulk melt temperatures in the melt by a non-invasive technique, using an ultrasound 'virtual instrument' operating at 10Hz sampling of transit time. Process induced change in the polymer melt is also monitored using the same technology.

In-Line Monitoring of Multiple Additives in Polyethylene Melt Using Fiber-Optic Spectroscopy

Jigui Li, Marion G. Hansen, May 1999

The feasibility of simultaneous in-line monitoring of additives Irganox 1076®, Irgafos 168®, Tinuvin 622®, erucamide, and Armostat 310® in molten low-density polyethylene (LDPE) was studied. The near-infrared (NIR) and ultraviolet (UV) spectroscopic systems used for the determination of additives were described. Based on the Partial Least Square (PLS) multivariate regression analysis, calibration models were built for predicting the concentrations of additives. It was found that some additives can be predicted reliably.

The Euro - A Common European Currency or a Milestone on the Way to a United States of Europe?

Barry H. Massey, May 1999

The European Monetary Union is a further step in economic and political integration in Europe. The driving forces include the desire for reduced financial transaction costs and avoidance of exchange rate volatility. Eleven countries have fulfilled the criteria, and have applied to join. Many companies have not appreciated the likely impact of EMU, and have done little to comply. This paper describes methods of evaluating the effect of the EMU on company operations.

Integrated Approach to Cleaning during the Recycling Process

May 1999

With an ever-present desire to increase the amount of plastics, being recycled, specifically PET and HDPE, a premium has been put on optimizing the whole recycling process. This process involves many steps including collection, sortation, cleaning and reuse. Each of these steps includes many stages with varying degrees of sophistication. In this paper we will look specifically at the cleaning process and the parameters effecting cleaner performance.

Novel Heterojuctions Based on Conducting Polymers

M. Aldissi, E. Lazaro, M. Bhamidipati, B. Dixon, May 1999

This paper describes the fabrication and characterization of junction devices based on the combination of conducting polymers and nanoparticles or nanotemplates of n-type inorganic semiconductors for photovoltaic and thermoelectric applications. Several materials, the choice of which derives from their stability, solution processability and film forming properties, have been synthesized. We have explored in this effort the use of electron transfer materials in order to optimize the barrier interface. Characteristics of the novel heterostructures are described.

Optimization of Injection-Molding Process with Genetic Algorithms

Hua Ye, K.K. Wang, May 1999

Injection molding is widely used for mass production of polymer products. One important issue is how to determine the gate location(s) and process conditions to produce parts of the best quality. The objective of this paper is to develop an efficient optimization system that can automatically make such determination. The Genetic Algorithm (GA) will be compared with a functional search method, Simulated Annealing (SA) algorithm. The principle of both algorithms will be described and illustrated with examples. Application of these algorithms to determine gate location and optimal process condition in injection molding will be demonstrated with examples. Gate location is determined based on the principle of balanced flow paths, while the optimal process condition is computed by minimizing the warpage across the entire part. Results show that the Genetic Algorithm is more efficient computationally than the SA algorithm.

Reduce Costs and Get Better Product Using Your Own SPC System on Your Line at Your Profile Extruder's Plant: A Customer's Perspective

Chris Rauwendaal, David Hadden, May 1999

SPC (Statistical Process Control) is a powerful tool that can be used to enhance quality and increase productivity in profile extrusion lines, but the number of custom extruders that use SPC is limited. When the right extrusion vendor can be found who is open to new ideas and is willing to work in partnership with a customer with basic SPC skills, it is possible to increase part quality and reduce costs simultaneously. For $3,500 plus a low end laptop and one of the popular spreadsheet programs, a simple, portable and powerful SPC system can be built, assembled, and programmed. All hardware and software is commercially available. Only a limited knowledge of instrumentation, statistics, and the ability to design and use a spreadsheet program is necessary to employ the methods presented. An example is presented wherein a customer brought his own portable SPC system into his profile extrusion company's shop and used it to troubleshoot the process, improve the quality of the customer's product, and decrease manufacturing costs by increasing production rates.

Influence of the HDPE Grade on the Blow Moulding of a Bottle: A Numerical Investigation

Benoît Debbaut, Gerrit Rekers, May 1999

A numerical investigation is performed on the influence of the properties of the high density polyethylene properties on the final thickness distribution of a bottle. The K-BKZ integral model with a relaxation spectrum is used for modelling the rheology of the material. A membrane element is used for performing the simulation of the blow moulding of geometrically complex objects, and is combined to a Lagrangian representation for the equations governing the motion. The simulation tool is applied for the production of a bottle with a handle. Numerical predictions on the thickness distribution of the part are compared to available experimental data.

Utilizing an Engineering Resin Supplier's Technical Support

Frank C. Jaarsma, May 1999

Many molders, designers and resin specifiers do not realize the extent of technical resources available to them by the suppliers of engineering resins. Whether an application is still a concept or currently in production, questions may arise regarding properties or processing of a material. Engineering resin suppliers are generally well equipped to provide guidance in material selection, design, processing and trouble shooting for applications using their materials. This paper will provide an outline of the types of services and data commonly available. Guidelines will be provided for obtaining maximum utilization of the resource for large customers, small customers and even non-customers.

The Six Marketing Secrets for a Profitable Web Site - What Works and What Doesn't

Martin K. Pottle, May 1999

The real secrets to profitable Web Sites are content, content and more good content, along with some interesting tricks, plus understanding the audience. Learn what works to get buyers to visit and then repeatedly come back to your Web Site. Paradigm shifts, although infrequent, change all the rules. Such has been the case with the advent of E-marketing, considered by many to be one of the greatest paradigm shifts of this century. What it has done is enable companies to have dialogues with large numbers of individuals at very little cost; and given companies the ability to keep track of individual habits, estimate individual desires and work to satisfy them.

Polyblends of Polystyrene and High-Impact Polystyrene with Styrene-Ethylene/Butylene-Styrene Thermoplastic Elastomer

Rudolph D. Deanin, Anand Damani, Stephen A. Orroth, May 1999

Styrene-ethylene/butylene-styrene sandwich block copolymer thermoplastic elastomer was added to polystyrene and to high-impact polystyrene to increase ductility and impact strength. While it decreased modulus, strength, and heat deflection temperature, it did increase the elongation and impact strength of polystyrene greatly, and was superior to conventional rubber-modified polystyrene, both in impact strength and in overall balance of properties. Conversely, addition of polystyrene or high-impact polystyrene to styrene-ethylene/butylene-styrene thermoplastic elastomer did not seriously decrease its rubbery elasticity.

Mistaken Identity: Prevention of Failures Due to Improperly Supplied Resins

Steven W. Bradley, May 1999

Product performance problems are often related to design, molding, or misuse by the end user. However, a more fundamental problem may be a wrongly supplied or inferior resin that can lead to poor performance or failure. Two examples are presented for illustration. Case 1 involved a change in polyolefins supplied for an air filter, which reduced performance. Case 2 was an ergonomic polystyrene chair arm that experienced multiple cracks during shipment in the winter months causing multiple returns to the manufacturer. Methods for material determination in these two cases are shown as well as recommendations for quality control testing to prevent poor products from leaving the factory.

Extrusion Design with the Carreau Model

J. Thomas Lindt, May 1999

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.

In-House Blending of Polypropylene with EPDM

Rudolph D. Deanin, Ashish B. Shah, Carol M. Barry, May 1999

A custom processor can inventory one hard and one soft resin of good compatibility, and blend them in various ratios to manufacture a wide range of products. In a model study of polypropylene (PP) with ethylene-propylene-diene rubber (EPDM), all ratios from 100/0 to 0/100 showed good practical compatibility. Adding 20% of EPDM to PP increased impact strength 5X; while adding 20% of PP to EPDM doubled tensile yield strength, producing a thermoplastic elastomer. Extrusion pre-blending favored elongation, rebound, recovery, and impact strength; while direct blending during injection molding favored modulus and strength.

Flow-Induced Morphological Changes Inpoly(Styrene-Co-Maleic Anhydride)/Poly(Methyl Methacrylate) Blends

Divya Chopra, Dimitris Vlassopoulos, Savvas G. Hatzikiriakos, May 1999

The effects of shear flow on the phase behavior of a polymer blend with high glass transition temperature, Tg, constituents possessing large viscosity difference were investigated in the linear and non-linear regime using shear and capillary rheometry. This was complemented by differential scanning calorimetry and analysis of the extrudates with scanning electron microscopy. The blend is a lower critical solution temperature polymer mixture of a random copolymer of styrene and maleic anhydrite, SMA (Tg=178°C), and poly (methyl methacrylate), PMMA (Tg=105°C). The methodology presented here for the determination of the shear-induced phase diagram should be applicable to any industrial mixture. The activation energy analysis in the phase separated SMA/PMMA(50/50) blends predicted cylindrical domain morphology in the non-linear regime. The latter was confirmed by SEM of the phase separated SMA/PMMA(50/50) extrudates, associated with high shear rates, where fibrillar domain structure was observed in the shear direction.

The Effect of the Boron Mitride Type and Concentration on the Rheology and Processability of Molten Polymers

Franky Yip, Eugene E.Rosenbaum, Stuart K. Randa, Savvas G. Hatzikiriakos, Charles W. Stewart, May 1999

The influence of a new processing additive (a composition of fine particles of boron nitride) on the rheology and processability of molten polymers is studied. The equipment used includes both an Instron capillary rheometer with special annular dies (Nokia Maillefer wire coating crosshead) attached to the rheometer and a parallel-plate rheometer. A metallocene polyethylene and Teflon FEP with several types of boron nitride varying in particle size distribution are tested at various concentration levels. The additive with the finest particle size has the greatest influence in crosshead dies and tips. As a result, its use eliminates surface melt fracture and postpones the critical shear rate for the onset of gross melt fracture to significantly higher values depending on the additive concentration. The influence of the boron nitride type and its concentration on the polymer rheology is also discussed. It is found that the activation energy for flow of Teflon FEP scales with the BN concentration.