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

Resin Design for High Stiffness and High ESCR Performance in Rotational Molding Applications

Celine Bellehumeur, Tracy Li, Mark Hoidas, Yves Lacombe, Henry Hay, May 2013

This paper presents new developments in the design of ethylene copolymers for rotational molding applications with higher stiffness and ESCR requirements. The performance of novel ethylene copolymers is discussed based on phenomena fundamental to the rotomolding process and on the relative impact of the choice of comonomer, manufacturing technologies and resin design strategy.

Relating Polymer Viscoelastic Properties to Thermoforming Process: A Short Review

Rabeh Elleithy, May 2013

This paper reviews the relation between polymer viscoelastic properties and the plug-assist thermoforming process. One of the important attributes of polymers is their macromolecular interaction. Molecular interaction provides enhanced networks of molecules that contribute to minimizing polymer deformation at high temperatures. As a result, sheet sagging will be reduced during thermoforming. Additionally, molecular interaction could enhance the melt strength of the polymer by reducing its molecular mobility.

Upgrading the Capacity of an Existing Extrusion System

Mark A. Spalding, Gregory A. Campbell, May 2013

Several low-cost techniques are readily available to upgrade the capacity of an existing extrusion system. These techniques include upgrading a screw to restore the flight clearance due to wear, changes to the motor drive train system, and the use of high-performance screws. The technique used will depend on the rate limitation and the current process.

Troubleshooting and Mitigating Gels in Polyolefin Film Products

Mark A. Spalding, Eddy Garcia-Meitin, Stephen L. Kodjie, Gregory A. Campbell, May 2013

The term “gel” is commonly used to refer to any small defect that distorts a film product. Eliminating gel defects from extruded polyolefin film products can be difficult, time consuming, and expensive due to the complexity of the problem and the high levels of off specification product produced. This paper discusses the identification of gel types, the common root causes for gels, and the technical solutions for mitigating gels in film products produced using single-screw extruders.

Comparison Study of Talc and Nanosilica as Nucleating Agents for Low-Expansion Foaming Applications

Mo Xu, Anson Wong, Chul B. Park, May 2013

This paper compares the effectiveness of talc and nanosilica as nucleating agents for generating polypropylene foams with high cell density and low expansion. Experiments were conducted in two stages: 1) In-situ foaming observation in a batch system; 2) Extrusion foaming. Nanosilica was more effective than talc in inducing cell nucleation under static conditions. However, in extrusion, their effectiveness in enhancing cell nucleation was similar due to the presence of extensional and shear stresses.

Fiber length and orientation distribution measurement of a charge for D-LFT compression Molding

Camilo Perez, Steffen Roppers, Tim A. Osswald, Umesh Ghandi, Raghuram Mandapati, May 2013

Initial fiber orientation distribution (FOD) and fiber length distribution (FLD) of a fiber glass reinforced polypropylene charge for a D-LFT compression molded part were measured using image processing techniques. The FOD was measured from ?-CT scans using two different image processing approaches. These results are intended to be used in compression molding simulations.

Considerations regarding the EN13900-5:2005 determination by filter pressure value test

Justin Abel, May 2013

With the increasing demands on masterbatches the DIN EN13900-5 standard has been used as a more stringent and objective indicator of dispersion quality in a polymer matrix. Introduced within the last 7 years this method is being widely adopted in the industry. This paper will examine the history and the key components needed to assess the dispersion of a colorant in a masterbatch as well as equipment considerations.

Reliable Damping Parameters for Simulating Flow of High Molecular Weight HDPE

Tieqi Li, Wen Lin, Tracy Li, May 2013

Determination of damping parameters from uniaxial extensional flow data per K-BKZ/PSM model are evaluated for high molecular weight HDPE resins. It was found that the damping properties depend on strain rate. The strain dependence, however, cannot be represented reproducibly as the relaxation mode-dependent ?k per Luo-Tanner from SER data. More efficient description of the strain dependency remains to be further explored.

Laser Transmission Welding for Medical Devices

Kai Holl, Thomas Seul, Udo Behn, Michael Gehde, May 2013

Laser transmission welding is a well established joining technique for molecular diagnostic devices such as lab on a chip. This paper provides an overview about the effects of the injection molding parameters and the joining process parameters on weld strength. Design of experiments was used to maximize the weld strength. Additional optical and microscopic tests are required to validate the process for medical devices.

Die Design Effect on Internal Die Drool Phenomenon

Martin Zatloukal, Jan Musil, May 2013

n this work, the effect of die exit design on the internal die drool phenomenon occuring during extrusion of HDPE has been experimentaly investigated. It has been revealed, that firstly, the effect of flared length and die exit angle on the internal die drool intensity during extrusion of HDPE has non- monotonic character and secondly, flared dies are more stabilizing in comparison with chamfered dies.

Influence of the Endgroup Nature on the Rheological Behavior of Branched Polycarbonate Resins

Jean-Francois Morizur, May 2013

Branched polymer rheology represents a very active field of research with important challenges, both from the scientific and technological point of view. A study of the rheological properties of branched polycarbonate resins is presented. The effect of the endgroup nature on the polymer melt viscosity was investigated.

A New Rheometer Concept Extending the Capabilities of Rotational Rheometer

Jörg Läuger, May 2013

A new rheometer concept based on two air bearing supported motors is introduced. The combination of two motors into one rheometer system offers increased sensitivity and new testing capabilities not possible before. Three completely different testing modes such as combined motor transducer, separate motor transducer and counter rotation are available in one single rheometer system. The aim of the paper is to describe the new technologies involved and to outline applications.

Cavity-Integrated Injection Molded Accoustic Foams

Davoud Jahani, Peter U. Jung, Amir Ameli, Amir Ameli, Chul B. Park, Hani Naguib, May 2013

An injection molding machine enhanced with gas counter-pressure was used to produce cavity integrated acoustic foams using mold opening technique. The cell morphology of the produced foams in different mold opening lengths was studied. An automated perforating system was developed to perforate acoustic foams. Acoustic behavior of the produced foams with and without perforation was studied.

Reliability of Weld Join Under Fatigue Conditions

Haiying Zhang, Zhenwen Zhou, May 2013

This paper focuses on reliability of glass-reinforced polyamide (PA) vibration welded joints with respect to fatigue. It presents a statistical extension of the thermodynamic model of lifetime under creep into reliability model under creep and fatigue. The paper also presents in detail a method of obtaining Weibull distribution parameters employed in the model. The proposed reliability analysis can be easily implemented for weld joint design.

Processing and Characterization of High Speed Extruder for Nanocomposite Formulations

Jacob J. Boone, Gregory Pigeon, Christopher Thellen, Jo Ann Ratto, Robert Whitehouse, May 2013

Ethylene Co-Vinyl-Alcohol (EVOH) blends were compounded on a high speed extruder, with kaolinite loading levels at 0, 3.0, and 7.5%. Extruded samples were processed with varying screw speeds (0 to 3000rpm) and feeder rates, and then characterized for dispersion, thermal, and mechanical properties.

Modeling polyurethane foam flow in a mold with constricted vents

Krishnamurthy Jayaraman, Christopher J. Hershey, James T. McEvoy, May 2013

A computational flow model has been developed that accounts for the volume expansion and viscosity behavior of thermosetting polyurethane foam with water as the blowing agent in pour molding of polyurethane foam. This model was then used to investigate the effects of (a) varying pour distribution and (b) restricted air flow through vents on the merging of expanding flow fronts and air pocket formation in a vented rectangular mold cavity with a rigid rectangular insert.

Basic Day-Night Laser Ablation

Jacob Wieloch, May 2013

Lasers have been used for over 10 years to ablate paint layers in day-night applications. Over this time, there has been a lot of confusion over how laser systems are set up to perform this application. This paper will address different variables that effect how lasers interact with paint and why each variable is important to the process.

Lead-Free, Low Smoke Zero Halogen LV Power Cable Jacket

Jason Zhang, May 2013

A new lead-free, low smoke zero halogen (LSZH) low voltage power cable jacket compound was developed based on customer requirements. This jacket was formulated based mainly on an ethylene co-polymer matrix with magnesium hydroxide and other inert inorganic fillers to improve and optimize overall performance. The new jacket shows enhanced dielectric and flame retardant performance with much lower smoke release while maintaining comparable mechanical properties to previous (lead-containing) formulations.

Characterization of CNT Orientation and Diameter Distribution in CNT/Polymer Composites by Image Analysis

Md A. Bhuiyan, Raghuram V. Pucha, Kyriaki Kalaitzidou, May 2013

The focus of this research is to determine the distribution function of CNT characteristics such as orientation and diameter of CNT within the polymer matrix and investigate how these characteristics affect the tensile modulus of the CNT/ polypropylene (PP) composites. An image analysis approach combining scanning electron microscopy (SEM) and a selective etching technique allows for extraction of 3D information that is used as input in a finite element model.

Morphological Characterization of Poly(Ether Ether Ketone)

Lin Jin, Jerry Ball, Tim Bremner, Sue Hung-Jue, May 2013

The crystal structure of poly(ether ether ketone) (PEEK) has been investigated by thermal and morphological characterizations. Spherulites and lamellar structures are revealed by optical microscopy, atomic force microscopy, transmission electron microscopy and small angle X-ray scattering. A refined crystalline model is proposed to describe lamellae formation in PEEK.