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

NMR Analysis for a Secret Ingredient

P.R. Lewis, May 2004

Finding very small amounts of a secret compound in complex mixtures presents a big challenge for analysts. A dispute between two companies involved building plasters with a polymer viscosity modifier. The case hinged on confidential information about the exact structure of the polymer, which one company had apparently taken illicitly from the other. FTIR revealed little, so NMR was used to identify the compound in deuterated DMF extracts from the plasters. They showed that the plasters possessed compounds of identical structure. The case was settled without trial.

Detecting Defects and the Onset of Failure of Adhesive Bonds Using Electrochemical Impedance Spectroscopy

Suresh Mani, Michael J. Rich, Robert J. Jurek, Lawrence T. Drzal, Guy D. Davis, May 2004

Tape sensors were mounted on the adherends and the health of the adhesive bonds was studied by electrochemical impedance spectroscopy. Results show that EIS measurements can discriminate bonded and unbonded areas in CFRP-Al systems. The EIS measurements are also sensitive to the weakening of adhesive bonds caused by exposure to humidity at high temperatures.

Microscopy and X-Ray Elemental Spectroscopy in Failure Analysis: Case Studies

Kevin P. Battjes, May 2004

Optical and Scanning electron microscopy (SEM) techniques, coupled with energy dispersive X-ray analysis (EDS) are effective tools in investigating the cause of failures in articles made from plastics. Practical examples and findings are reviewed that have been used to solve customer problems in real world applications.

Thermal Properties of ? Nucleated Polypropylenes

Martin Obadal, Roman ?ermák, Roman ?abla, Karel Stoklasa, May 2004

Commercially available isotactic polypropylene (iPP) was modified by various amounts of a specific ?- nucleating agent. Isothermal crystallization and subsequent melting behavior were analyzed using differential scanning calorimetry (DSC). The findings resulting from this work (such as crystallization halftimes, other kinetics parameters, glass transition temperatures, etc.) can significantly assist to explain not a few open questions concerning ?-nucleated polypropylenes and their processing.

Method for Measuring the Kinetics of Isometric Crystallization of Thermoplastic Sheets and Patient Fixation Devices

Bogdan Bogdanov, May 2004

A new method for crystallization kinetics of stretched polymer samples and real size polymer articles under isometric conditions is developed. The internal shrinkage force caused by the volume contraction of the sample during crystallization is measured incessantly. The kinetics parameters of isometric crystallization are calculated by the Avrami equation and discussed in terms of controlled molecular structure and design of large polymer sheet samples and of patient fixation devices for medical application in radiation therapy.

Viscosity of Blowing Agent Laden Polymer

Subir K. Dey, David B. Todd, Chen Wan, May 2004

The viscosity of a blowing agent laden polymer was measured using a Helical Barrel Rheometer (HBR). Temperature, pressure and shear rate dependence of viscosity at a fixed blowing agent concentration was computed from the experimental data. Technique was developed to identify the onset of bubble nucleation by measuring the shear viscosity as function of hydrostatic pressure.

Structure-Property Relationships in Coextruded Foam/Film Microlayers

Aditya Ranade, Anne Hiltner, Eric Baer, David Bland, May 2004

It has been demonstrated for the first time that microcellular foam structures can be produced using the microlayer coextrusion technology. Cell size can be reduced considerably by increasing the number of layers without adversely affecting the density. Unique mechanical properties can be achieved through material choice and layer structure. The cell morphology and the compressive response of these multilayered foam/film structures are similar to that of cork.

Processing and Properties of Foamed HDPE/PP Blends by Extrusion

E. Herrera Tejeda, C. Zepeda Sahagún, R. González Núñez, D. Rodrigue, May 2004

This paper presents a study on the processing condition and characterization of foamed HDPE/PP blends. The blends were foamed with different blowing agent concentrations using a twin-screw extruder. A chemical blowing agent (azodicarbonamide) and activator agent (ZnO) were selected and the morphological, rheological and mechanical properties of the resulting foams are presented.

Effect of the Filler Content on the Specific Properties of Syntatic Foam

Erwin M. Wouterson, Freddy Y.C. Boey, Xiao Hu, Shing-Chung Wong, May 2004

In this study we assessed the specific properties including tensile, compression and flexure strengths and moduli for syntactic foam as a function of various microstructures. Preliminary results revealed that the specific compressive strength and the specific tensile, compressive and flexural moduli depended on the type of microsphere, which varied in density. Mechanical properties are critically evaluated in light of their microstructures.

Capillary Rheometry Studies on Wall Slip Flow of Ceramic Pastes

A. González-Álvarez, J. Graczyk, H. Buggisch, May 2004

The extrusion behavior of ?–aluminium oxide– silicone oil pastes were investigated via capillary rheometry. Several parameters affecting the paste behavior were considered, including the viscosity of the fluid phase, the solids concentration (35 to 55 Vol. %), the extrusion rate (10-2 to 103 mm/s) and the addition of pigment. The flow curves and wall slip behavior were determined under the extrusion conditions.

Synthesis of Blocky Copolymers via Ring-Opening Polymerization Using L,L-Lactide and MBC

Adam J. Pesek, May 2004

A semi-crystalline copolymer was synthesized with block-like structures by ring-opening polymerization (ROP) using L,L-lactide (LLA) and 5-methyl-5- benzyloxycarbonyl-1,3-dioxan-2-one (MBC). Analysis of the copolymer revealed retention of crystallinity and melting transition temperatures. The copolymer exhibited an upper limit to compositional incorporation of MBC before crystallinity was disrupted. The physical properties (Tg, Tc, Tm) were increased after hydrogenation.

Novel Impact Modification in Olefin Systems

Anna P. Andrews, Vicky Bryg, Anthony Dean, Paul DeFranco, Ann Panek, May 2004

Unique additives enable increases in the Gardner impact strength of polyolefins by a factor of 10 while maintaining up to 90% of the material flexural modulus. The effects of resin and additive loading level are addressed in a statistically designed experiment. Physical performance, rheological effects, thermal characterization, and morphological characterization are reported.

Dynamic Rheological Properties of Polypropylene Containing Thermoplastic Elastomer Compounds

W.G.F. Sengers, P. Sengupta, J.W.M. Noordermeer, A.D. Gotsis, May 2004

The dynamic rheological properties of two types of thermoplastic elastomer (TPE) compounds were studied at ambient and processing temperatures. The linear viscoelastic properties of Thermoplastic Vulcanisates (TPV) and PP/SEBS compounds can be described using models based on mechanical mixing rules. The results were evaluated as a function of composition.

The Comparasion of a Short-Term and Long-Term Capital Market Investment Tools

Zden?k Raska, May 2004

The article discuss the evaluation of ways of investment occasions on a capital market, taking under consideration the availability and cost of investment money. It is considering the time-factor related to the actual market environment an describing the specific possibilities of the trading tools as the technological conciliator of the investment in the chemical and plastic industry.

The Genealogy of Polymers

Barbara J. Gedeon, May 2004

The supply chain for polymeric materials is a drastically changing environment. This paper will focus on the types of trade names used. Changes of ownership along with historic trade names will be discussed. Predictions of future uses and types of trade names will be made.

On the Breakup of a Non-Newtonian Drop in an Extensional Flow

Moshe Favelukis, Olga M. Lavrenteva, Avinoam Nir, May 2004

The condition for the breakup, of a power-law non-Newtonian slender drop in a Newtonian liquid in an axisymmetric extensional flow, has been theoretically studied. The problem is governed by four dimensionless numbers: The capillary number, the Reynolds number, the viscosity ratio and the power-law index. The results suggest that the critical capillary number for drop breakup increases as the Reynolds number, the viscosity ratio and the power-law index decrease.

Molecular Dynamics Simulation of Nano-Scale Polymeric Rheological Properties and Extrusion Flows

Rong-Yeu Chang, Jenn-Jye Wang, May 2004

In this work the rheological properties of polymer have been studied by molecular dynamics simulation. Couette flow with various shear rates are used to investigate the degree of slip, shear viscosity and normal stress difference. The fluid consists of chains of n-hexadecane and is confined between two structured gold atomic walls. Isothermal simulations (350K) of 4 to 1 unsteady extrusion flow with various extrusion rates are conducted.

Optimization of a Flat Die Geometry

Y. Sun, M. Gupta, May 2004

Geometry of a flat die for polymer sheet extrusion is optimized to obtain a uniform velocity distribution across the exit of the die. While optimizing the exit velocity distribution, the constraint optimization algorithm used in this work enforced a limit on the maximum allowable pressure drop in the die. Effect of the shear as well as elongational viscosity of the polymer on the flow in the flat die is taken into account.

The Effect of Stabiliser Type and TiO2 Concentration on the Rheology of uPVC Profile Formulations

W.C. Yap, A.C. Ruddy, K. Halliwell, G.M. McNally, W.R. Murphy, May 2004

A range of unplasticised polyvinylchloride (uPVC) profile extrusion grade formulations, containing calcium/zinc, organotin and lead based stabiliser systems were blended with different concentrations of TiO2. Rheological analysis showed that the concentration of TiO2 (2phr - 8phr) had little effect on viscosity over the shear rate (200-1000s-1) and temperature range (170 – 190°C) studied. Mechanical analysis showed higher tensile and flexural modulii for the organotin stabilised formulations.

Medical Grade Copolyesters for Profile Extrusion

Daniel C. Cobb, Thomas J. Pecorini, Marc A. Strand, Eric J. Moskala, May 2004

Resins used in profile extrusion require high viscosity at low shear rates to improve melt strength and low viscosity at high shear rates to prevent melt fracture. This paper discusses the development of copolyester resins with the desirable rheological properties, as well as good optical and physical properties. The processing, biocompatibility, and sterilization of these resins will also be discussed.