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

Orientation on Polyimide Sliding Surfaces Studied by Raman Spectroscopy

Pieter Samyn, Patrick De Baets, Jeroen Van Craenenbroeck, Francis Verpoort, Gustaaf Schoukens, May 2005

Small-scale tribological tests are performed on sintered polyimides in the temperature range between 80°C and 260°C. A transition towards low friction is observed at 180°C corresponding to stabilisation in wear rates. This characteristic is further related to an endothermal reaction in the polymer bulk as revealed by TGA/DTA and reorientation of C=O and C-N-C bonds as studied by Raman spectroscopy.

Monitoring Polymerization in Microfluidic Flow Channels Using Spectroscopy Methods

Anthony J. Bur, Zuzanna T. Cygan, Kathryn L. Beers, Susan E.Barnes, May 2005

A micro-fluidic device, designed as a high throughput system for characterizing polymerizations over a range of solvent, monomer, initiator and temperature conditions, was instrumented with a fluorescence spectrometer. A fluorescent dye, incorporated into the monomer at very low concentration, was used as a molecular viscosity probe to monitor changes in viscosity during the polymerization of acrylic polymers. The measurement provides information about the extent of polymerization.

Magnetic Rotor Encapsulation

Wes Childers, Jay Sayre, May 2005

Magnetic rotors are used in bearingless pumps for wet processes in the semiconductor industry. These rotors must be encapsulated so that they resist corrosion from the aggressive chemical environment and do not permit permeation of the metallic ions from the rotor to the outer fluid. This paper describes our approach to evaluating fluorinated materials and processing techniques to produce encapsulated prototypes. Eighteen prototypes were manufactured and evaluated for testing. Details regarding this work are presented.

Cavity Temperature Control in Injection Molding Machine

J.M. Hernandez, R. Dubay, B. Pramujati, May 2005

A new approach for controlling part cooling in plastic injection molding is developed using a PI controller and coolant flow rate as the manipulated variable. The method uses an average part surface temperature within the mold as the setpoint parameter. A mechatronic system was developed for providing variable coolant flow rates. The control strategy was simulated using plant models, and then implemented and tested on a 50 tonne injection molding machine with good closed loop responses.

Effects of Vibrating Injection on Structure and Property of Polymer Produce

Peng Xiangfang, Xu Chao, Zhang Fengling, Lin Yiquan, Zhou Nanqiao, May 2005

A novel Vibration Injection Molding (VIM) Machine was introduced. Under factual manufacture conditions in a VIM machine, the effects of the vibration parameters on the structures and mechanical properties of HDPE, PP and HIPS materials were researched. It was discovered that vibrating injection can obviously improve the micro-structures and mechanical properties through optimizing vibration frequency and amplitude conditions of injection screw.

Experimental Investigation of PET and PP Film Casting

Kenneth Aniunoh, Graham Harrison, May 2005

In film casting, a polymer melt is extruded through a die before rapid cooling on a chill roll. The process stretches the material and induces some orientation in the film. In this paper, we study experimentally the effects of processing variables such as the draw ratio and the die temperature on film formation. The temperature, width and velocity profiles in the air gap are measured for films produced using polypropylene and polyethylene terephthalate.

Weatherability and Physical Properties of Opaque Injection Moldable Lexan* SLX Resins

Paul Sybert, Steve Klei, Dave Rosendale, Jianbo Di, Dake Shen, May 2005

New opaque blends and copolymers based on resorcinol phthalates have excellent weatherability and polycarbonate-like physical properties. The unique weatherability of these resins comes as a result of a photogenerated UV absorber (UVA) on the surface of a part. The gloss retention of these resins can be varied through proper selection of the resorcinol phthalate content and color package.

Transparent Injection Moldable Lexan* Slx Resins

Gheorghe Cojocariu, Chris Blubaugh, X Y Li, Jon Malinoski, Paul Sybert, May 2005

New copolymers based on resorcinol phthalates have excellent weatherability and polycarbonate-like physical properties. The excellent retention of optical and mechanical properties on weathering of these resins is the result of the polymer’s ability to form a UV absorber at the surface of a part.

New Non-Hygroscopic Thermoplastic Vulcanizates with Improved Colorability and Weatherability

Kevin Cai, Hamid Tavakoli, Hoan Tran, Satchit Srinivasan, May 2005

A new line of non-hygroscopic thermoplastic vulcanizates (TPVs) has been developed for applications requiring both color and photo-oxidative stability. These products span the hardness range from 20A to 50D and offer superior oil resistance and compression set. In this paper, we will discuss the properties of the new TPVs, including non-hygroscopicity, oil resistance, compression set, color consistency, colorability and weatherability.

Development of Damping Machine Augmented Composite Materials

D.M. McCutcheon, J.N. Reddy, O. Ochoa, M.J. O’Brien, T.S. Creasy, G.F. Hawkins, May 2005

This work investigates energy dissipation in machine augmented composite (MAC) materials consisting of small machines in a matrix. The machines are fluid-filled tubes, and the tube cross-sectional geometry causes fluid flow when deformed. Dimensional analysis identifies the ratio of solid moduli to the product of driving frequency and fluid viscosity as an important parameter. Finite element models predict the performance of the MAC lamina. The highest energy dissipation predicted is 0.8 out of 1.0.

Active Polymer Composite for MEMS Applications

S.J. Lee, T.S. Creasy, G.F. Hawkins, M.J. O’Brien, May 2005

Finite element analysis (FEA) simulated the performance of an active polymer-matrix-composite material. Microscale muscle elements actuate the material. The muscle element contracts longitudinally, expands transversely, and twists when pressurized. A coupled elastic/piezoelectric element provided the response of the muscles to actuation and 3D elastic coupling of the lamina. The contractions of isolated elements and of a lamina were approximately the same; elastic coupling of elements within the lamina produced novel out of plane deformation.

Increasing the End-Use Temperature of TPU Products

Oliver Henze, Armando Sardanopoli, May 2005

TPU products are well known for their mechanical properties and wear resistance. However, in comparison to vulcanized rubber TPU materials have a lower softening point (limited end use temperature) and a limited elasticity (elongation set) preventing the use of TPU in some interesting applications. Here we introduce a family of new cross-linking agents and how they can improve these properties. Application examples are shown to demonstrate how these improvements can be utilized.

Mechanical Properties Enhancement via Non-Conventional Injection Molding

D.B. Tchalamov, A.M. Cunha, May 2005

This work explores the possibility to expand the limited mechanical properties enhancement margins, typical for conventional injection molding, through the application of non-conventional techniques. The processing-structure-properties relationships encountered in two microstructure control methods (Scorim and Push- Pull) and three two-component techniques (Sandwich molding, Monosandwich molding and Overmolding) are evaluated and discussed.

Terahertz Imaging as a New Tool to Study Dispersion in Polymeric Compounds

F. Rutz, M. Koch, K. Kretschmer, M. Bastian, May 2005

We use terahertz (THz) imaging to study polymeric compounds of polypropylene and the flame retardant agent Mg(OH)2 obtained for different compounding conditions. Our data demonstrate that THz imaging is a powerful tool to evaluate the degree of dispersion in polymeric compounds.

Modeling for Counter-Rotating Twin Screw Extrusion

Krzysztof Wilczynski, James L. White, May 2005

Based on our previous experimental studies for polymer behavior in a closely intermeshing counterrotating twin-screw extruder of a modular Leistritz design a composite model for the process is discussed. The model includes solids conveying, melting and melt conveying. Melting model involves both mechanical working of pellets in the inter-screw region and heat transfer from the barrel to the pellets.

Effect of Screw Design on Polyethylene Blown Film Processing

M T Martyn, G D Smith, R Spares, PD Coates, May 2005

The influence of extruder screw design on the extrusion blown film processing characteristics of four polyethylene melts was studied. A barrier and standard compression screw were evaluated and process measurements including; process energy, melt pressure and melt temperature determined. Screw design had significant influence on melt throughput and specific energy.

Effect of Vibration Shear on Polystyrene Cell Morphology

Changyun Gao, Nanqiao Zhou, Xiangfang Peng, Danchao He, Ping Zhang, May 2005

A novel microcellular processing experimental setup is developed. With this setup, an oscillatory shear flow is superimposed perpendicular to a steady shear flow during microcellualr processing. The effects of processing condition such as processing pressure, shear rate and vibration frequency on polystyrene cell morphology are investigated. The results show that the cell density increase and cell size decreases with the increase of processing pressure, shear rate and vibration frequency.

In-Situ Observation of Orientation during Injection Molding with a Delayed Packing Stage

David C. Angstadt, John P. Coulter, May 2005

In-situ, real time monitoring of melt birefringence during injection molding of SAN provides insight into the development of molecular orientation when the packing/holding phase is delayed relative to the fill phase. Observation of melt birefringence is accomplished through the use of a custom-built mold and video imaging. The effects on orientation are similar to those observed using Vibration Assisted Injection Molding (VAIM) and provide a similar increase in the tensile strength of molded ASTM specimens.

Growth through Innovation

Jack Avery, May 2005

Today’s business environment is more challenging than ever. Globalization, outsourcing, consolidation and increasing raw material prices impact our business daily.Innovation takes many paths. In today’s environment, innovation must provide value, which translates into growth. The simplest and in many cases, the most rewarding innovation is achieved by recognizing the synergy between ideas that are not obviously connected.

Describing the Non-Linear Viscoelastic Material Behavior of Thermoplastics

Ernst Schmachtenberg, Thorsten Krumpholz, Marcel Brandt, May 2005

The significance of structural analyses (FEA) for the dimensioning of plastic parts is heavily dependent on the material model used to describe the mechanical behavior. At the Institute of Plastics Processing (IKV) a new nonlinear viscoelastic material description was developed and implemented as a subroutine in the ABAQUS/Standard FEA program. Part tests confirm the high level of simulation quality for loading cases of practical relevance.