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

Toughened Blends of Polystyrene and Ethylene-Styrene Interpolymers

Chung P. Park, May 1999

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.

Barrier Properties of Thermoplastic Polyurethane Film for Bladders and Other Containment Applications

Dirk Schultze, May 1999

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

Gary Fong, May 1999

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

C. Rosales, R. Perera, H. Rojas, May 1999

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.

Non-Isothermal Effects in Injection Molding of Rigid Fiber Suspensions

K.K. Kabanemi, J.F. Hétu, May 1999

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

Choon K. Chai, May 1999

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.

Infrared Characterization of Vinyl Cinnamate Copolymer Blends before and after UV Exposure

Michael M. Coleman, Yin Hu, Paul C. Painter, May 1999

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

Antje Stein de Vilchez, Witold Brostow, Prakaipetch Punchaipetch, Syed Maswood, May 1999

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

John F. McClelland, Roger Jones, Stan Bajic, May 1999

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

J. González, C. Rosales, M.N. Ichazo, H. Rojas, May 1999

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

K.A. Narh, J. Guo, M. Xanthos, U. Yilmazer, V. Tan, May 1999

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

John Hahn, May 1999

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

L.-S. Turng, D. DeAugistine, May 1999

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.

Investigation of the Rheological Properties of Rotomolding Resins

Alvin Spence, May 1999

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

Guido Bendrich, Rickey Dubay, May 1999

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

Debbie Hauser, May 1999

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

Todd D. Cook, May 1999

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

Ch. Bonten, May 1999

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.

Computer Simulation of Plastics Compounding Operations in Twin-Screw Extruders

Eduardo L. Canedo, May 1999

This presentation is concerned with the development of process simulators for the analysis of compounding operations in modular corotating intermeshing twin-screw extruders. Approximate flow and heat transfer models are presented and implemented in a personal computer based software package for the fast simulation of the processing behavior in realistic settings.

Microlayer Coextrusion Technology

E. Baer, D. Jarus, A. Hiltner, May 1999

Coextrusion with three or more layers is commonly used to produce end products that have properties with a good mix of the individual components. Layer multiplying technology allows for coextruded samples to be multiplied into tens or even thousands of layers, producing microlayers. In this manner, a wide variety of polymers can be combined intimately with minimal mixing. Microlayers have several distinct advantages as both a research tool and as a method of producing end products with enhanced properties. The effect of large interfacial area and of scaling is discussed with several example systems.