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

Thermal Stabilization of High Molecular Weight L-Polylactide

Jérôme Burlet, Marie-Claude Heuzey, Charles Dubois, Paula Wood-Adams, Josée Brisson, May 2005

Polylactide (PLA) polymers are among the most promising plastic made from renewable resources. Thermal stablization of these polymers remains a challenging issue of their industrial processing. We have studied the effect of TNPP in the scope of preventing the molecular weight reduction of PLA at its processing temperature. The stabilizing effect of TNPP was found to strongly depend on the concentration used.

Thickness Optimization of Blow Molded Parts Using FEM/AANN/GA Methods

Geng-Qun Huang, Han-Xiong Huang, May 2005

An artificial neural network (ANN) model based on the numerical simulation data was developed to build the relationship between parison thickness distributions and part thickness distributions. A real-coded genetic algorithm (GA) was used to search for the optimal parison thickness distributions to produce a blow molded part with a uniform thickness distribution. The results showed that the hybrid method was an effective algorithm to optimize the parison thickness.

Temperature Profiles within Reheated Preform in Stretch Blow Molding

Han-Xiong Huang, Yan-Hong Deng, You-Fa Huang, May 2005

A thermal model was developed for the perform reheating in the two-stage injection stretch blow molding. The temperature distributions through the thickness of the preform and along its length were obtained by solving the model with ANSYS finite element software. With the use of real-time temperature measuring system, experiments were carried out to obtain the temperature evolution within reheated preform as it rotated. The numerical results were compared with experimental data.

Preparation of Interconnected Polycaprolactone Porous Scaffolds by a Combination Polymer and Salt Particulate Leaching

Joël Reignier, Michel A. Huneault, May 2005

Porous poly(?-caprolactone) (PCL) scaffolds were prepared by melt blending PCL with poly(ethylene oxide) (PEO) and NaCl salt particulates using twin-screw extrusion, followed by leaching out of water soluble PEO and NaCl. Scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) were carried out to caracterized their morphology. The scaffolds were highly porous (75-85%) and exhibited an open cellular pore structures.

Viscosity Measurement of PS/CO2 Solution at Low Temperatures

Jang-Hoon Oh, J. Thomas Lindt, May 2005

The shear viscosity of solution of polystyrene(PS) in supercritical carbon dioxide(CO2) was measured at low temperatures between 100°C and 130°C at CO2 pressures up to 21MPa using Couette viscometer. The flow curves allow reasonable estimates of the zero shear viscosity as a function of temperature and pressure, otherwise difficult to obtain. Measured viscosity at Newtonian region was correlated to the WLF (Williams, Landel and Ferry) equation.

Oriented Porous Poly(L/DL-Lactide) Scaffolds for Bone Regeneration

Megan E. Oest, Angela S.P. Lin, Thomas H. Barrows, Robert E. Guldberg, May 2005

A new structure of poly(L-lactide-co-30%-DLlactide) PLDL created by a unique process that formed oriented longitudinal pores in combination with smaller random pores fully interconnected throughout was evaluated in vivo to determine its ability to facilitate bone regeneration in a critical size defect in the rat femur. Using quantitative micro-CT analysis, the PLDL-treated defects exhibited significantly greater bone volume and vascular volume fractions than untreated defects at 16 weeks post-operation.

Bismuth Oxychloride for Radiopaque Medical Devices

Qinyun Peng, May 2005

Bismuth oxychloride has been used as filler for many applications for several decades. The unique properties of bismuth oxychloride, such as high radiopacity, excellent physical and chemical stability, high density and good dispersibiltiy, make it one of the ideal fillers for radiopaque products, such as radiopaque medical devices. Detailed comparisons of bismuth oxychloride with commonly used fillers for radiopaque medical devices were performed.

Segmentation, Lamination and Post Processing of Amorphous Thermoplastic Urethane

Scott M. Epstein, May 2005

Medical Device Labs, Inc. proprietary segmenting and lamination technology processes have been developed for their (SMEthane™)1 TPU (Thermoplastic Urethane) and (pAguaMedicina™)1 super porous structural hydrogel. These materials are based on well-known formulae in combination with qualified processes that have been used to produce FDA approved Devices, such as the TigerTail 2 Ureteral Catheter.

Do Nanoparticles Really Assist in Nucleation of Fine Cells in Polyolefin Foams?

N.S. Ramesh, S.T. Lee, May 2005

Nanotechnology is an enabling technology that is extremely large to cover in one technical paper. It touches various technology disciplines and covers several applications. The purpose of this paper is to investigate the effect of nanoclay on nucleation of polypropylene foams. Particularly, the goal is to understand the ability of nanocomposites in producing finer cells compared to talc in polypropylene.

Materials Characterization Based on Ultrasonic Spectral Analysis

C.H. Chen, May 2005

In this paper the use of ultrasonic spectral analysis in material characterization is examined. Though the discussion is mainly on metallic materials, the basic ideas and techniques are mostly applicable to polymers and plastics.

A Novel Technique to Measure Tensile Properties of Plastics at High Strain Rates

Luke Perkins, Hubert Lobo, May 2005

High strain-rate properties have many applications in the simulation of automotive crash and product drop testing. These properties are difficult to measure. Difficulties arise from inaccuracies in extensometry at high strain rates due to extensometer slippage and background noise due to the sudden increase in stress at the start of the test. To eliminate these inaccuracies we use an inferential technique that correlates strain to extension at low strain rates and show that this can be extended to measure strain at higher strain rates

Impact of UV Exposure on Aesthetic and Mechanical Properties of Thick Rotomolded Articles

Raed Al-Zubi, Brian Weick, Ryan Fournier, May 2005

If not adequately protected, polyethylene is prone to degradation when exposed to the ultraviolet (UV) component of sunlight. Long-term direct sun light exposure was performed on thick rotomolded polyethylene samples. The impact of this exposure on aesthetic and physical properties, such as elongation at break, gloss, and color, was measured for polyethylene resins commonly used in the rotomolding industry. Molded samples from dry blended powder as well as compounded color powder were used in this research.

Plastics and Creativity

Rolf Koster, May 2005

Unlike other materials, the number of polymeric materials and material combinations with polymers grows rapidly. Consequently, design opportunities daily arise but not all of them may be reconized instantly. Some opportunities are discovered by chance. A short review is presented about past design opportunities and when they were reconized, as well as a vision on design opportunities of some current developments, such as various types of new copolymers compatibilized blends, polymeric semiconductors and nano-structured materials.

High Performing Pigmented Rotational Molding Applications

Joachim Jandke, May 2005

This paper focuses on the key criteria to achieve high performing rotationally molded plastic articles. The rotomolding process as well as the final applications lead to the highest requirements for pigment and additive selection. An overview is given on possible critical steps in the whole production cycle and in detail the influence of the pigment selection on the processing and end-use quality is described. On a practical example, where extreme weather resistance is required, it is demonstrated how to transform this knowledge into an integrated solution for the Industry.

Geometry Dependent Flow Properties of Long Glass Fiber Reinforced Polypropylene

Peter J. Farrington, Russell G. Speight, May 2005

Long glass fiber (LGF) reinforced resins have established a strong presence in the injection molding industry. Optimising the mechanical properties requires control of fiber orientation during molding. CAE simulations have proven beneficial in mold design; however these simulations depend on the quality and relevance of the rheological properties. The flow behaviour of LGF grades measured in a variety of rheometric geometries is presented.

Prediction of Flow Imbalance in Geometrically Balanced Feed Systems

Peter S. Cook, Huagang Yu, Clinton V. Kietzmann, Franco S. Costa, May 2005

Experimental data are presented for a multi-cavity molding which show a significant flow imbalance despite a geometrically balanced feed system. The degree of the imbalance between inner and outer cavities depends on the injection rate and is also found to change as filling progresses. Three dimensional computer simulations have successfully predicted these trends and provide an understanding of the behavior in terms of shear heating and laminar convection.

Interfacing Process Setting Data between Analysis and Machine Control

Xiaoshi Jin, Paul Brincat, Baojiu Lin, Zhongshuang Yuan, May 2005

Interfacing mechanisms between specially designed tools for both analyzing the injection molding process and automating machine setup of the process are presented in this paper. We use examples to show that the interface is an effective way to communicate between the two tools and so benefit both analysts and manufacturers by achieving process conditions that are both consistent and based on scientific principles.

QC of Polyolefin Manufacturing by Rheology and Multivariate Analysis

Svein Eggen, May 2005

The paper will focus on explaining some of the fundamental techniques of multivariate analysis (principal component analysis) and show examples on how such techniques can facilitate use of rheological measurements in offline and online QC of polyolefin manufacturing.

New Technologies for Achieving Lean and Six Sigma Goals

Steve W. Tuszynski, May 2005

A pioneering system of interrelated algorithms— which integrates prior art techniques from the fields of correlation, regression, mapping, statistics and decision-making— has led to breakthrough insights into plastic injection molding processes. This new technology accelerates time-to-market, increases quality and reduces cost and risk during development. It increases quality and greatly reduces measurement, SPC analysis and Cpk analysis costs during production. Changes to tooling, targets and tolerances can be simulated without incurring cost, time or risk.

Study on Mechanical Properties of ABS Parts in Microcellular Injection Molding Process

Chaur-Kie Lin, Shu-Hwang Chen, Horng-Yith Liou, Chieh-Chih Tian, May 2005

The study uses a fixed amount of ABS as matrix, mixed with supercritical fluid (N2) in different proportions, in order to obtain foamed ABS. The resulting product of the above is a structured foamed ABS, by which to research into the MuCell process. The results of the study indicate that increasing the amount of the blowing agent will obviously improve the warpage and shrinkage, but this will also decrease the strength of tensile and impact.