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
Characterization of Biaxial Orientation in Polyolefin Films
A. Ajj, K.C. Cole, May 2000
Among the most widely used orientation processes are those involving films; they include both film blowing (with a low level of orientation) and biaxial orientation or tentering (with a high level of orientation). Polyolefins (polyethylene, polypropylene, polystyrene, and their copolymers) represent a significant proportion of the polymers commonly used in these processes. The knowledge of the orientation developed in these films is critical for establishing the process conditions and the final properties of the films. In this study, we investigate the biaxial orientation developed in blown and biaxially oriented polyethylene films using Fourier transform infrared (FTIR) spectroscopy and birefringence. Biaxial orientation factors are determined for both crystalline and amorphous phases and discussed in relation with process conditions.
Evaluation of Layer Spreading in Coextruded Structures via a Modular Die
Joseph Powers, Joseph Dooley, Carl Reinhardt, Gary Oliver, May 2000
Layer spreading in coextruded sheet structures remains a problem solved more often with art than with science. A modular die, i.e. a die with inserts for the entrance channel and for the manifold, was designed and evaluated for a range of entrance shapes, manifold shapes, and resins. The results from these experiments lead to an improved selection process for die designs for coextruded sheet.
An Experimental Investigation of the Effect of Polymer Processing Additives (PPA) on the Melting and Gel Formation Mechanisms in a Single Screw Extruder
K.R. Slusarz, J.P. Christiano, Stephen E. Amos, May 2000
Much work has been published showing how the addition of a polymer processing aid (PPA) has improved the processing characteristics on the single screw extruder. This paper will give insight on how the PPA affects a single screw extruder. Solids conveying, melting, and melt conveying were experimentally studied to determine how the PPA affected these important processes during extrusion leading to improvements in the melt quality.
Effects of Varying Strand Length on Shielding Properties of Conductive Elastomers in Near-and Far-Field Experiments
Douglas Luther, May 2000
A new study examined the effects of varying the strand length of extruded conductive thermoplastic elastomer (TPE) pellets on the shielding efficacy of plaques molded of the material in both near- and far-field experiments. Results indicated that longer strand lengths yielded parts with higher shielding efficacy but at a cost of higher durometer and modulus. Data also indicated that far-field results were consistently higher than near-field values for the same materials and frequencies.
Measuring the Low Frequency Linear Viscoelastic Properties of Polymer Melts: Trials with PDMS Using Sphere-Plane Squeeze Flow and Interferometry
Edwin C. Cua, Montgomery T. Shaw, May 2000
The problem of measuring the linear viscoelastic (LVE) properties of polymers at low frequencies is a long-standing one, especially for polyolefins with broad relaxation times and small time-temperature shift factors. A squeeze flow apparatus utilizing Newton's interference rings has been devised to measure minute strains at very low stresses with a minimum resolution of ¼ wavelength of light. Its simplicity allows several samples to be run simultaneously under vacuum. This arrangment minimizes degradation, manhours and cost, all critical considerations for long experiments. The design and preliminary results for PDMS as measured by a prototype of the instrument will be discussed.
New Polypropylene for Differentiated Blown Films
W.D. Hoenig, C.P. Bosnyak, K. Sehanobish, W. Van Volkenburgh, C. Ruiz, L..M. Tau, May 2000
New polypropylene resins have been developed which allow for the commercialization of novel, air-quenched blown films. The new resins have been developed using molecular design principles and provide significantly enhanced properties. Key performance properties include stiffness, seal strength, and higher service temperature for many applications as well as flexibility and toughness for other applications. This new breadth in product offerings and performance ranges provides significant new opportunities for PP resins in blown films. This paper will highlight properties and processability of the new resins.
Physical Model of Polymer Pellets Melting in Co-Rotating Twin-Screw Extrusion
Zhu Linjie, Geng Xiaozheng, May 2000
The melting of polymer in co-rotating twin-screw extruder depends not only on screw configurations and operational conditions, but on the properties of the polymer as well. The melting progressing is too various to be described by single melting model. Only in the past few years (1-9), some attention has been paid to the research of polymer melting in co-rotating twin-screw extrusion. In present study, based on experimental results, the conception of melting sub-stage was defined to describe the complex polymer melting progressing in co-rotating twin-screw extrusion. Ten melting sub-stages were concluded and defined. It was found that the complicate polymer melting progressing can be modeled by combining some of these ten melting sub-stages. It showed that the definition of melting sub-stages would provide an important way to the research of polymer melting in twin-screw extrusion.
Numerical Analysis on the Melt Conveying Properties of Wave Screw Element in Intermeshing Counter Rotating Twin-Screw Extruder
Zhou Fuping, Geng Xiaozheng, May 2000
In this paper, one new kind screw element, wave screw element in intermeshing counter-rotating twin screw extruder, is designed. Three-dimensional Non-Newtonian model is established to investigate the melt conveying properties of this new screw elements. The model consists of all the gaps between the screws and the barrel such as the side gap, the calender gap, the flight gap, and the tetrahedron gap, which is in accordance with the true extrusion process. With the finite element software ANSYS, velocity, pressure and viscosity field are obtained respectively. Experiments are used to verify the results of simulation. It shows that the calculated results such as output is nearly the same as the experimental results.
Morphology/Property Relationships in Thermoplastic Starch/Poly(hydroxy ester ether) Biodegradable Blends
P.S. Walia, J.W. Lawton, R.L. Shogren, F.C. Felker, May 2000
The effect of moisture level during processing on the mechanical properties of biodegradable blends of thermoplastic starch and poly (hydroxy ester ether) (PHEE) was studied. The morphology of the blends changed with the moisture content of starch. The dispersed phase was significantly deformed under high moisture conditions, leading to fibrillar and laminar types of morphologies at 50-80% starch level. A low moisture level produced a more dispersed morphology. Improved tensile properties were observed for the blends processed at high moisture levels due to the presence of elongated morphologies.
Measuring Frosted Glass Effects for Plastics: A Closer Look at One Frosting Agent
Tracy Phillips, May 2000
To produce consistent frosted plastic effects it is necessary to measure basic performance characteristics of the frosting agents. Frosted plastic, like frosted glass, serves a variety of aesthetic and functional needs. In testing, the most crucial characteristics are transmittance, haze, clarity and yellowness This paper examines two sets of data: 1. Comparative results of testing a series of frosting agents at differing loads 2. Specific, in-depth results of testing a single frosting agent at differing particle sizes.
Improvement of the Molded Part Quality-Optimization of the Plastification Unit
S. Boelinger, W. Michaeli, May 2000
The three-zone plastification screws traditionally used in the injection molding process are nowadays limited in their efficiency. Reasons are increasing demands on the quality of the molded part and on the machine technology which is more and more adapted to the different process groups like packaging or optical parts. Therefore different types of screw geometry, e.g. barrier screws or multi-threaded screws, are used to investigate the influence of the dosing parameters and the screw geometry on the melting capacity and the homogeneity of the melt .
Carbon Dioxide Extrusion Foaming of Engineering Thermoplastics
Martin Gale, May 2000
Many engineering thermoplastics require extrusion temperatures which are too high for foaming with chemical blowing agents. Carbon dioxide foaming by direct super critical fluid injection has no such restrictions as well as offering economic benefits. This study describes preliminary work on a laboratory scale extrusion line using retrofitted parts to produce foams from a number of engineering polymers. Results of an evaluation of a very simple low cost method for measuring melt strength (an important polymer property with regard to foaming) is also included.
Effect of Nanosilica on Properties of Segmented Polyurethanes
Zoran S. Petrovi, Young-Jin Cho, Ivan Javni, Wei Zhang, May 2000
Thermoplastic polyurethane elastomers having soft segment concentration (SSC) of 50% and 70% were synthesized in the presence of 12 nm silica nanoparticles. The concentration of nanosilica was varied from 0% to 30% in both series. Nanosilica had not significant effect on glass transition of the soft segment but it increased tensile strength and particularly elongation at break. Tear strength of the series with 70% SSC was not affected by the presence of nanosilica while initial decrease was observed in the series with 50% SSC.
Mechanical Properties of Starch Filled Poly(hydroxy ester ether) Biodegradable Composites
S. St. Lawrence, J.L. Willett, C.J. Carriere, May 2000
The mechanical properties of starch filled biodegradable composites have been investigated. The strength was found to be independent of the filler content below 10 vol% and above approximately 30 vol%. This behavior is due to the failure mechanism operating in these composites. The matrix, poly(hydroxy ester ether) (PHEE), adheres well to starch and as a result the granules do not dewet during deformation. Instead the composites behave as a quasi-homogeneous material with increased brittleness as the filler content increases. The deformation mechanism was investigated by acoustic emission analysis and by a post-mortem examination of the fracture surfaces.
Mold-Making Apprenticeship Program in Georgia
William T. Thielemann, May 2000
This paper will trace the development of the Mold-Making Apprenticeship Program in Georgia's technical institutes, developed to support the plastics industry within the state. It will explain why the program was developed, how it was developed, the content of the program and the results to date. The purpose of the poster presentation is to explain the process and outline the program with the goal of assisting other states with similar programs and ultimately addressing the shortage of trained and available mold-makers. The poster presentation will include three sections: industry growth and potential, team process and program outline.
Regulatory and Experimental Approaches to FDA Food Contact Compliance
Robert L. Pesselman, Melanie McCort-Tipton, May 2000
Tests to determine the migration of indirect additives into actual foods are essential in order to ensure food safety. Recent changes in regulatory protocols and evolving analytical technologies have helped define new ways to receive regulatory clearance for food contact polymers. This poster summarizes the issues to be addressed when designing a test plan and outlines regulatory considerations and experimental approaches applicable to both Food and Drug Administration (FDA) and European compliance. In addition, the proper use of food simulants, available extraction cells, and analytical techniques are discussed.
Profit from Recycling Tooling and Leadership Change
Wilhelm O. Morgan, May 2000
This paper is about upgrading tooling that has been built many years ago, or simply to make mouldings to suit our type of manufacturing operation. When these tools were built the techniques and technology used was the latest available to the polymer technologist designer, mould shop and toolmaker. Using tooling technologies as the starting point, I have added management, and more so Leader techniques to show how production can be changed and opportunities gained, by modernising; towards increasing production, saving money, material, and bringing about attitudinal changes. This paper will concentrate on the following topics, and show details where this revisiting process has changed tools and people to make them more motivated about competition, which will result in profitable, faster cycling and be better suited to today's fast operational needs.
Wood Flour Reinforced Polystyrene Composite Using SEBS-g-MA as Compatibilizer
Chen-Jui Hung, Jenn-Fong Kuan, Jaine-Ming Huang, May 2000
A functionalized thermoplastic elastomer, SEBS-g-MA (styrene-ethylene-butadiene elastomer grafting maleic anhydride), has been demonstrated to be an effective compatibilizer in polystyrene-wood flour composite and results in the formation of an in-situ formed copolymer existing between the interface of polystyrene and wood flour and thus enhance the interface adhesion and mechanical properties of the composite. With the addition of SEBS-g-MA, both flexural modulus and impact strength of polystyrene-wood flour composite has been improved substantially and a good interaction between polystyrene and wood flour can be indicated by Scanning Electron Microscopic (SEM) images as well. The result shows that composite with 4phr SEBS-g-MA gives the optimum mechanical property.
Dispersion of Nanoscopic Clay Particles in Thermoplastic Polymers
Grant D. Barber, Christopher M. Carter, Robert B. Moore, May 2000
The formation of clay nanocomposite, hybrid materials will be achieved through the incorporation of organically modified montmorillonite clay particles within a variety of thermoplastic polymers. In order to facilitate a homogeneous dispersion of the clay nanoparticles in the thermoplastic matrix, ionomeric compatibilizers will be utilized. The matrix polymer/ionomer pairs chosen for this study include polystyrene/sulfonated polystyrene, PET/sulfonated PET, and polypropylene/carboxylated polypropylene. Various methods of clay dispersion, including melt-processing, in-situ polymerization, and solution-state mixing will be utilized and compared. The morphology and physical properties of the resulting nanocomposites will be investigated using SAXS, TEM, DSC, TGA, DMA and standard tensile test methods.
Effect of Water Sorption on Mechanical Properties of Fiber Reinforced Dental Resin
A. Prasad, A. Karmaker, May 2000
Composites from different glass fibers reinforced in dimethacrylate based dental resins were prepared for flexural tests in accordance with ISO 10477. Tests were conducted on both dry specimens and on specimens stored in water for 7 days at 37°C. Depending on type and amount of fibers, the strengths were found to decrease from moderate to minor. Loss of strengths correlated with the constituents of fibers.
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