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
AFM Study of Ultrathin Tri-Block Copolymer Films on Tailored Grafted Polymer Layer
Igor Luzinov, Vladimir V. Tsukruk, May 2002
AFM was used to study the morphology of ultrathin poly[styrene -b- butadiene -b-styrene] copolymer (SBS) films deposited on polystyrene brushes. The grafting density and molecular weight of the grafted polymer layers were varied to reveal the relationship between the parameters of the brush interface and the structure of the film. We found a strong effect of the underlying brushes on the formation of the SBS films.
Analysis of Large Diameter Polyethylene Piping Failures
Donald E. Duvall, May 2002
Large diameter high density polyethylene (HDPE) pipe, typically with diameters greater than 300 mm (12 inches) often have very different failure modes than smaller diameter pipe of the same materials. Heavier wall thicknesses, sometimes greater than 50 mm (two inches), are more susceptible to oxidation during manufacture. The aqueous media transported in such pipes may also oxidize the pipe wall. Such pipes are also often more susceptible to excessive deformation by soil settlement. In this paper, failures in three different large diameter HDPE systems will be investigated.
An Analysis of the Fiber-Fiber Interactions Using the Fragmentation Test and Optical Coherence Tomography
Walter G. McDonough, Gale A. Holmes, Joy P. Dunkers, May 2002
Multi-fiber model composites are being used in studies into the nucleation of failure in composites. Results have revealed that the nucleation of critical flaws in unidirectional fibrous composites may rely on the time-dependent redistribution of stress by the viscoelastic matrix. Although their role in flaw nucleation is not clearly understood, shear deformation bands have been detected between fiber breaks. Furthermore, interfacial phenomena have been detected in the matrix by Optical Coherence Tomography.
Analysis of the Polymer-Pellet-Flow into the First Section of a Single Screw
H. Potente, T.C. Pohl, May 2002
The flow of plastics pellets between the first flights of a single screw can lead to conveying problems. As a result, the throughput varies or not enough material reaches the following screw sections. In order to gain a better insight in the correlations that exist between pellet properties, barrel and screw geometry, a physico-analytical model is worked out. On the basis of this model, the pellet flow behavior can be analyzed relatively accurately.
Analysis of Tiger Striping in Injection Molded TPO
K. Jayaraman, P. Papworth, Chichang Shu, M.D. Wolkowicz, May 2002
Tiger striping in injection molded bars made of thermoplastic olefin (TPO) blends has been examined by a detailed analysis of the disperse phase morphology. This is evaluated in flow mark regions and out of flow mark regions on the part surface and near the wall, and also just behind the flow front but away from the wall. The results point to a way to control the rheology of the components for avoiding or delaying the onset of flow lines.
Annealing of a Co-Continuous Polystyrene/Polylactide Blend and its Influence on the Morphology
Zhenhua Yuan, Basil D. Favis, May 2002
In this paper, polystyrene and polylactide were blended at a composition of 50/50 to form a co-continuous morphology. The influence of annealing on the final morphologies of the blend is investigated using SEM and Mercury Intrusion Porosimetry. It is demonstrated that a series of co-continuous networks with pore sizes ranging from 1 to 80 microns and higher have been achieved by varying the annealing conditions. A mechanism of coalescence is discussed in order to account for the said morphologies.
Application of Ultrasound in the Determination of Fundamental Extrusion Performance: Barrel and Screw Wear Measurement
C.-K. Jen, Z. Sun, M . Kobayashi, M . Sayer, C.-K. Shih, May 2002
Ultrasonic stand-alone and film-type high temperature sensors and system have been used to measure in-line the barrel and screw wear during low-density polyethylene extrusion. These sensors are nonintrusive and non-destructive. For the screw wear measurement the system is equipped with fast data acquisition. Measurement accuracy of better than 50 ?m can be achieved.
Application of a Single Screw Extruder Simulation towards Design
Jiri Vlcek, John Perdikoulias, May 2002
This paper provides an overview of the application of extrusion simulation towards process analysis and screw design. The paper discusses some of what is possible today with computer aided screw design; what can be obtained from simulation results, what the limitations are, and shows a couple of examples of how to apply simulation towards design.
Application of Small-Angle X-Ray Scattering to the Lamellar Thickness Analysis in Semicrystalline Polymers
Zhiyong Xia, Hung-Jue Sue, Zhigang Wang, Benjamin S. Hsiao, May 2002
The determination of the crystalline lamellar thickness in semicrystalline polymers is a tricky issue. In this paper, three methods have been employed to analyze the lamellar thickness in semicrystalline polymers. The three methods are small-angle X-ray scattering correlation function method, Fast Fourier Transformation and transmission electron microscopy. Based on this study, the larger value of the two correlation length values should be assigned as the lamellar thickness.
Application of Thermoplastic Elastomer Material Testing Data for Automotive Body Seal Analysis
Linhuo Shi, May 2002
Material recycling requirement gradually opens the automotive body sealing market to thermoplastic elastomers (TPE), which is primarily dominated by EPDM thermosetting elastomers. Due to special material behaviors of elastomers, careful attentions should be taken when analyzing the body seal performance using material testing data, especially for TPE materials. This paper will address some of the issues by analyzing body seal products using TPE materials. The general guidelines for body seal analysis and result evaluation will also be discussed.
Automated Plastication Setup for Injection Molding Machines
A.S. Bakharev, R.G. Speight, A.R. Thomas, May 2002
This paper presents a new algorithm for the automatic setting of the rotational speed, back pressure and barrel temperature profiles in a reciprocating screw injection molding machine. The algorithm is based on a computer simulation of polymer plastication. It achieves maximal throughput and good quality of melting and mixing within the limits provided by the injection molding machine.
Automated Set-Up for Gas Assisted Injection Moulding
L. Mulvaney-Johnson, P.D. Coates, R.G. Speight, May 2002
A process initialisation and setup system for the gas assisted injection moulding process is developed. The initialisation routine uses settings taken from the machine operator or machine controller to formulate the starting point for the process settings. A setup routine is required that automatically changes process settings on the machine controller to provide an acceptable product. Process variables are monitored along with feedback from the operator on the condition of the product. The process initialization routine is outlined here.
Avenues of Introducing Chaotic Mixing in Single-Screw Extruders
Sadhan C. Jana, May 2002
It is widely known that single screw extruders are poor mixers and improving mixing in single-screw extruders is a challenging task, especially under low shear conditions. In this paper, a methodology based on chaotic mixing sections, spread over almost half of the screw length, is described to improve mixing characteristics of immiscible and miscible polymer systems under low shear conditions.
Barrier Properties of a Thermotropic Liquid Crystalline Polymer
Hansel Ramathal, Adeniyi Lawal, May 2002
A developmental Thermotropic Liquid Crystalline Polymer (TLCP) made by Eastman with tradename LN001 was used for barrier property studies. The permeability of methanol and toluene through a membrane of the TLCP was studied using a two-part cell and a Gas Chromatograph to monitor the flux. The membranes of the TLCP and LDPE (as control) were made by compression molding. Both solvents had higher permeability through LDPE than TLCP and that of Toluene was higher than Methanol.
Barrier Screws, Their History and Their Function
Edward Steward, May 2002
This paper will briefly discuss the history of barrier screws and then discuss the design features and resulting performance in single screw extruders. Barrier screw operation in smooth feed and grooved feed machines will be discussed. Comparisons of barrier screw performance to conventional screws will show where the benefits lie and a few examples of where there is less advantage or even disadvantages with barrier screws.
Blend of Polypropylene-G-Poly(Methyl Methacrylate) and Bisphenol-A-Polycarbonate
T.T.M. Phan, C. Shu, May 2002
A novel reactor-made polypropylene-g-poly(methyl methacrylate) (PP-g-PMMA) was used as a component for forming binary blends with bisphenol-a-polycarbonate (PC) and ternary blends with PC and polypropylene (PP). Results showed that the morphology and physical properties of these blends were strongly composition dependent. The compatibility window was determined based on the physical properties and the morphology. The binary blend of PP-g-PMMA/PC shows excellent chemical and stress cracking resitance as compared to PC.
Blending of Immiscible Polymer Systems by Chaotic Mixing
Madhusudan Sau, Sadhan C. Jana, May 2002
A novel feature of chaotic mixing, that of formation of self-similar mixing structures, is utilized in this study to produce an array of mixing microstructures, such as nested layers, elongated fibrils, droplets and their combinations in the blending of two immiscible polymers, polypropylene (PP) and polyamide-6 (PA6). The effects of initial length scale of segregation, viscosity ratio of the phases, mean shear rate, and the degree of chaotic mixing are studied.
Brittle-To-Ductile Transition Temperatures of Miscible Copolyester/Polycarbonate Blends
Emmett D. Crawford, May 2002
The brittle-to-ductile transition temperatures (TBDs) for miscible copolyester/polycarbonate blends are studied using single edge notched bend specimens. The pure copolyester TBD and pure polycarbonate TBD are lower than the TBDs of copolyester/polycarbonate blends. This decrease in toughness is evaluated by examining the yield strength and craze strength as a function of temperature and blend composition.
Case Studies Illustrating the Four Primary Causes of Product Failures
Michael P. Sepe, May 2002
Material selection, part design, mold design, and processing must all receive proper attention in order to prevent product failure. This paper will profile case studies of failed products where each one of these fundamentals was neglected. The studies will illustrate the analytical processes used to assign a root cause to each of the problems and will suggest corrections that can prevent costly failures from recurring.
Cast-In-Place (CIP) for Joining and Repairing Live, Polyethylene, Gas Lines - I. Basic Process Description
Robert A. Grimm, Arthur C. Eberle, May 2002
This paper describes a method for casting a non-leaking sleeve of polyethylene (PE) around the butted ends of PE pipes while the joint is leaking air at pressures up to 388 kPa. The step of casting the sleeve was the critical unknown step in a repair sequence that might be used to repair leaking natural gas pipes. Equipment, parameters, heating profiles, and the effects of mud and water on joint strengths are described.
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