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
Novel Phillips Loop-Slurry Based Polyethylene Resins Using Modified Chromium Oxide Catalysts for High Performance Pipe Applications
Paul J. DesLauriers, Max P. McDaniel, David C. Rohlfing, Rajendra K. Krishnaswamy, Steven J. Secora, Pamela L. Maeger, Elizabeth A. Benham, Al R. Wolfe, Ashish M. Sukhadia, William M. Beaulieu, May 2005
Novel high density polyethylene resins made in the Phillips Loop-Slurry Process (single-reactor), using a catalyst of chromium on modified aluminophosphate, were developed with unique structural attributes that make them especially suitable for high performance pipe applications. These structural attributes include high molecular weight (MW), very broad molecular weight distributions (MWD), effective levels of short chain branching in polymer chains with MW > 1,000,000 g/mol, and reduced levels of long chain branching (LCB). In particular, pipes made from these ethylene 1-hexene copolymers satisfy the performance requirements of PE100 specifications; in addition, these resins also offer outstanding slump (or sag) resistance for large diameter (> 24 inch) pipe processing. In this paper, a brief description of these catalyst systems is presented along with the unique molecular aspects of the resins. The physical properties of these resins and their fabricated pipe processing/performance properties are compared to several “bimodal” type resins.
Continuous Process for Melt Intercalation of PP-Clay Nanocomposites with Aid of Power Ultrasound
Sergey Lapshin, A.I. Isayev, May 2005
A continuous ultrasound assisted process using a single screw extruder with an ultrasonic attachment was developed to prepare PP/clay nanocomposites of varying clay concentrations. The feed rate that controls the residence time of the polymer in the ultrasonic treatment zone was varied. Die pressure and power consumption were measured. Rheological properties, morphology and mechanical properties of the untreated and ultrasonically treated nanocomposites were studied. An intercalation of polymer molecules into clay galleries and a partial exfoliation, which occur at short residence times (on the order of seconds), were observed as evident from measurements by X-ray diffraction and transmission electron microscopy. The obtained results indicate a possibility of the rapid intercalation and partial exfoliation of PP/clay nanocomposite without the matrix being chemically modified.
Effects of Composition and Functionality on the Properties of Thiol-Ene Films
Luke R. Kwisnek, May 2005
To understand the effects of both composition and functionality on thiol-ene cross-link systems, a diverse array of film systems were fabricated and tested. Di-, tri-, tetra-, and nona-functional thiol monomers were combined with di-, and tri-functional ene monomers at three different compositions: 40/60, 50/50, and 60/40, thiol/ene molar ratios based upon reactive functional groups. Polymerization kinetics studies were conducted using photo-differential scanning calorimetry and realtime Fourier-transform infrared spectroscopy. Experiments to determine glass transition temperature were done with DMTA.
What Every Plastics Professional Should Know about Patents and Patenting Part 1: An Overview of Patents and the Role of Claims in Defining Intellectual Property Rights Granted in Utility Patents
Amad Tayebi, May 2005
In this article, the legal right to exclude others, granted in a patent, and the commercial significance of patent protection are discussed as they relate to plastic materials, processes, processing equipment and products. Also, presented are subject matters that may be patented and who may apply for a patent. The article also deals with the requirements that every patent application must meet in order to be allowed. The anatomy of a typical patent and the role of the claims(s) in defining intellectual property rights are also discussed.
Polymeric Fuel Cell Membranes: Mechanical Properties and Durability
Ken Reifsnider, X. Huang, Matt Feshler, David Condit, Yue Zuo, May 2005
Polymers are essential materials for low temperature fuel cells. Proton Exchange Membrane (PEM) fuel cells typically feature a polymer electrolyte and usually include other polymer components as well. Design of PEM cells for high performance and (especially) for durability requires that the physical and mechanical properties be known, as a function of the operating conditions.The present paper reviews the nature of the applications of polymers in PEM fuel cells, discusses the required properties and related environments, and provides some sample results of investigations of the behavior of polymers typically used for these applications. The discussion includes linear, nonlinear, and fracture behavior.
A Study on the Crystallization Behavior and Morphology of PP/EPR Blends
Chin-Ching Lin, Yao-Kuei Hsiao, Chao-Yin Chuang, May 2005
The morphology and crystallization behavior of polypropylene/ethylene-propylene rubber blends were studied in this paper. The crystallization effect of the addition of EPR in PP was discussed via observation using a polarized optical microscope. The result shown that, with the addition of EPR in PP, the rate of crystallization became slower, the Maltese cross formation gradually disappeared and bead dispersion became evident. Through wide-angle X-ray diffraction analysis, with the addition of EPR in PP, the crystal size was smaller, and differential scanning calorimeter analysis showed that the melting point moved to a lower temperature. This paper also discuss the effect of different take-off temperatures on crystallization for different ratios of PP/EPR in the PP/EPR blend in the flat-film extrusion process. It was found that the crystallization degree and crystalline lamella size were greater at higher take-off temperatures than those at lower take-off temperatures.
The Electromagnetic Shielding Effectiveness of Carbon Nanotubes Polymer Composites
Wern-Shiarng Jou, Huy-Zu Cheng, Chih-Feng Hsu, Chia-Hao Hsu, May 2005
The effects of content and aspect ratio of carbon nanotubes (CNTs) upon the electromagnetic (EM) shielding effectiveness (SE) of CNTs polymer composites were investigated and developed. The multi-wall CNTs (MWNTs) with two types of aspect ratio (500 and 10,000) were compounded with three kinds of polymeric materials, such as Acrylonitrile Butadiene Styrene copolymer (ABS), liquid crystal polymers (LCPs), and Melamine resins (MF). The observed highest SE of these composites is 60 dB which is realistic for an industrial application (40 dB).
Enhancing Mixing Performance of Extrusion Process via Vibration Force Field
Zhou nanqiao, Luo weihua, Wu hongwu, Qing yanmei, Zhang zhihong, May 2005
Effects of vibration force field on dispersive mixing have been investigated during extrusion of a calcium carbonate filled LDPE system using a split barrel electromagnetic dynamic extruder, which introduce vibration force field into the whole extrusion process. The samples are collected along the length of the screw by barrel opening experiments and subsequently examined by means of scanning electron microscopy (SEM). The quantitative image analyses of SEM micrographs show that the introduction of vibration force field improves dispersion of calcium carbonate in LDPE matrix. With the same vibration amplitude, a higher vibration frequency leads to a smaller average particle size and a narrower particle distribution.
Thermal and Mechanical Properties of Recycled PET and its Blends
Parthasarathy Pattabiraman, Igor Sbarski, Tom Spurling, Edward Kosior, May 2005
This paper discusses the thermal and mechanical properties of virgin PET, recycled PET and their blends. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to study the thermal properties. The tensile tests at ambient and elevated temperature were used to study the mechanical properties. There were significant differences in the recrystallization behaviour as far as the thermal properties were concerned. In the case of mechanical properties, the tensile test at elevated temperature showed that the strength of the blends of recycled PET/virgin PET were lower than those ones of virgin PET.
True 3D CAE Visualization of Filling Imbalance in Geometry-Balanced Runners
C.C. Chien, C.C. Chiang, W.H. Yang, Vito Tsai, David C.Hsu, May 2005
The filling imbalance in geometrically balanced runner system of multi-cavities is always difficult to handle in injection molding. Previous researchers revealed that the flow imbalance problem is related to the three-dimensional thermal history and shear rate distribution of melt flow in the runner, and accordingly proposed a novel apparatus to overturn the melt to avoid this problem. However, the design parameter of this apparatus is different to realize, and it is only performed by trial-and-error. In this paper, we have proposed a new methodology to analyze this injection process. Firstly, a flexible meshing methodology comprising different element topologies is proposed to provide high-resolution mesh for the runner system and cavity. Further, to demonstrate and verify our idea, the comparison between simulation and experiments has been performed. From the numerical experiments, we have proven that the proposed methodology is a highly valuable tool to help understand and further optimize the melt flipping apparatus.
Development of PP/Clay Nanocomposite using scCO2 in Twin Screw Extruder
J.H. Han, S.M. Lee, Y.J. Ahn, H. Kim, J.G. Kim, J.W. Lee, May 2005
In this study, as a continuous processing method for the fabrication of polypropylene/clay nanocomposite, supercritical carbon dioxide (scCO2) was introduced in twin screw extrusion process. Supercritical CO2 was used for the purpose of improving dispersion of clay layers in PP matrix and diffusion of polymer chains into silicate layers. PP/clay nanocomposite was produced by two step extrusion processes. In first step, CO2 was injected into the barrel of extruder by CO2 metered injection system and the foamed extrudate was pelletized after solidification in water bath. In second step, CO2 in the foamed product was vented by vacuum pump. Finally, PP/clay nanocomposite without CO2 was produced. In this study, for the development of nanocomposite, the investigations were made for various cases such as variations in CO2 concentrations, maleic anhydride grafted polypropylene (PP-g-MA) concentrations and processing conditions. To confirm scCO2 effect, the comparison was made for the nanocomposites processed with and without scCO2 injection. The structures of the nanocomposites were investigated with X-ray diffraction and transmission electron microscopy. Mechanical properties were also evaluated.
Processing Effects on the Tribological Properties of Thermoplastics
Rolf Künkel, Gottfried W. Ehrenstein, May 2005
An important demand on engineering-technology is the optimization of materials for tribological stressed parts with regard to friction- and wear-behavior. To be able to use the full potential of improvement an optimum in processing is necessary. The morphology especially of the tribologically stressed surface-regions is influenced by the variation of mold- and melt-temperature. The dependence of tribological properties on processing conditions is shown for POM and PA66 in sliding contact against steel. The results of wear-tests are correlated with mechanical, morphological, and thermodynamic results.
Measurement of Strain Rate Dependent Material Properties for Polymers and Their Prediction from Normal Tensile Tests
S.R. Raisch, N. Woicke, P. Eyerer, May 2005
Present market forces dictate that the automotive industry must increase passenger safety. Since polymer material behavior are sensitive to speed, the determination of material data at crash relevant strain rates is of great importance.This study is concerned with a new method to predict the material behavior of polymers at high strain rates. The material data is determined with normal tensile tests and this material data is subsequently extrapolated to high strain rates. The results are compared and evaluated with those from high speed tensile tests.
Ranking of PP Pipe Grades by Their Failure Behavior under Impact Loads
Gerald Pinter, Zoltan Major, Markus Haager, Reinhold W. Lang, May 2005
In this work the influence of different test specimen configurations (different local and global stress states) on the brittle/ductile transition temperature TBD in PE pipe grades (PE 80 and PE 100) was characterized under impact loads at 1 m/s. It was found that TBD determined based on an energy criteria and fracture surface analyses was highly dependent on the stress state prevailing in the different test specimens. For all test specimens lower values for TBD were found for PE 100 in comparison to PE 80, corroborating the better performance of PE 100 under the different test conditions (from near plain stress to near plain strain conditions).
Through-Thickness Process Zone Characterization at Fatigue Cracks in PE-HD
Werner Balika, Gerald Pinter, Reinhold W. Lang, May 2005
Fatigue crack growth (FCG) experiments were conducted on different PE-HD pipe grades with CT specimens. All tests were interrupted in the region of stable crack propagation. The crack front and the front of the process zone ahead of the crack were systematically characterized via microscopic methods in the thickness direction of the specimen. The effects of stress intensity factor and frequency were systematically investigated. The experimental data are employed to study the mechanisms of process zone development and to determine the effective crack length by compliance relationships (instead of using optical methods).
PEO-Na+/MMT Nanocomposite Film as Polymer Electrolytes
Tithinun Puatrakul, Kyonsuku Min, May 2005
A polymer-clay nanocomposites of Polyethylene oxide (PEO) and Na+/montmorillonite (MMT) was prepared by a conventional melt blending method in an internal mixer. The level of intercalation of the composites of PEO with Na+/MMT layered silicates was crucial to influence the conductivity and mechanical properties as well as the thermal stability, which were studied by thermal analysis, FTIR and Wide Angle X-ray Diffraction. Thermal stability was also studied by using Thermogravimetric Analysis. The ionic conductivity and the impedance plots were measured by using an alternating current meter. It was found that PEO-Na+/MMT could be an alternative system for polymer electrolytes with high thermal stability, high tensile modulus and moderate ionic conductivity (10-6 Siemen cm-1).
A Study on the Extrusion of Open Cell Polystyrene Mixed Foams
Chih-Chen Chang, Mu-Li Chang, Pen-Chang Tseng, Chih-Hung Ying, May 2005
This current study mixes two polystyrene resins with different rheology properties, PS-1 and PS-2, to present the resin with other property, and finds that the adequate mixing proportion of PS-1 and PS-2 is better between 18~25%, and perlite additive is added to carry out the minute change of property, where 1-2% difference of perlite application quantity will cause changes in complex viscosity. For the application of formulation after property changes plus difluoromethane / pentafluoroethane 50/50Wt% foaming agent, we directly adopt continuous extrusion foaming method to execute the experiment, which shows such formula combination is capable of achieving better balance in simultaneously reducing average cell diameter of foam body and maintaining the open-cell content. Via the above mentioned formula combination and process condition, the foam body produced can possesses about 30?m of average cell diameter and open- cell content higher than 90%.
Unique Crystallization Behavior of ?-Polypropylenes
Jana Výchop?ová, Veronika Habrová, Roman ?abla, Martin Obadal, Roman ?ermák, May 2005
The work deals with the effects of ?-nucleation and thermal conditions on crystallization and resulting supermolecular structure of isotactic polypropylene (iPP). Neat and ?-nucleated iPP were crystallized under various conditions. Strong interrelation between crystallization temperature (Tc) and ?-phase formation was found. Moreover, the content of ?-phase was specifically affected by the nucleator concentration - increasing Tc depressed the formation of ?-phase in samples containing higher amount of the nucleator while this effect was inverse when low-nucleated samples crystallized.
Processing of Antimicrobial Nanocomposites and Their Characterization
M. Moneke, S. Khare, R. Hempelmann, N. Plachkov, M. Bureik, N. Lenz, May 2005
The volume of antimicrobial plastic materials in the healthcare and the food industry sector is growing rapidly. Different approaches to achieve antibacterial effects are followed. The technology discussed in this article is based on silver ion release.To obtain such antimicrobial nanocomposites, thermoplastic materials were processed with Agnanoparticles on TiO2 particles as carrier substance in a co-rotating twin screw extruder. Process parameters and the kind and amount of nanoparticles were changed to characterize their effect on the morphology, antibacterial and different mechanical properties using TEM, DSC, and tensile tests. In this work, the relation between these properties, the process parameters and the concentration of additives is presented. The processes of compounding and subsequently injection molding were optimized to get a plastic material with added value.
Clearweld™ Resins: Alternative Options for TTIR Clearwelds
Nicole Woosman, Matthew Curtis, William Cawley, Joe Verespy, May 2005
Clearweld is a through-transmission laser welding process promoted for the ability to generate colorless welds. A colorless weld is generated by applying the absorbing material only at the weld interface. The coating may be applied by a liquid dispensing method such as spraying, microsolenoid dispensing, etc. The limitation of the coating process is the secondary step of applying the coating.Clearweld laser absorbing additives were compounded into various resins to be used as the bottom substrate in a weld configuration. The resins eliminate the need for the dispensing step. The laser absorbing additive has minimal affect on the coloration of the part, which allows for a broad selection of colors, both transparent or opaque. The resin is typically injection molded but may also be extruded into a film for insert molding. This paper presents results of compounding the Clearweld additive into various polymers, including but not limited to Acrylic, polycarbonate, and polypropylene.
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