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.
The SPE Library is just one of the great benefits of being an SPE member! Are you taking advantage of all of your SPE Benefits?
Conference Proceedings
Optimization of Thermoforming
Petr Novotný, Petr Sáha, Karel Kouba, May 1999
There are many ways of optimizing the thermoforming process. However, any tuning of the processing parameters still remains a matter of experience. Using computer simulation software provides a way to explore various optimization possibilities without wasting machine production time, material and money through costly experiments. We have examined several methods of optimization using different materials, temperature, sheet thickness profiles and process parameters. For this purpose we have used the T-SIM® simulation program. This software uses a K-BKZ model capable to describe viscoelasticity and large deformation. The results of the simulations enable to determine which process parameters have the major influence and what are the pros and cons of each optimization method.
The Effect of Different Grades of Various Fillers on the Color Matching Process
Annmarie Danko, David Mekas, May 1999
What is color? “The committee on colorimetry of the Optical Society of America has defined color as consisting of the characteristics of light other than spatial and temperal inhomogenities, light being that aspect of radiant energy of which a human observer is aware through the visual sensations which arise from the stimulation of the retina”(Ahmed, p.1) Simply stated color is what we “see the result of the physical modification of light by colorants as observed by the human eye and interpreted in the brain. Knowing what color is alone is not enough we must also understand how we perceive it. The Perception of color depends on many factors such as the inherent color characteristics of an object the surroundings of an object and even by such individual factors like past experience and individual visual response characteristics. (Ahmed p.2) In order to study color one must first learn to describe observed differences in color between two objects. This can be accomplished through the use of the following three variables: hue (dominant color) value (lightness vs. darkness) and chroma (saturation or purity of color). These variables are known as the color coordinates and form the basis of the language system used in color description and specification. (Ahmed p.5)"
The Effect of Different Grades of Various Fillers on the Color Matching Process
Annmarie Danko, David Mekas, May 1999
What is color? “The committee on colorimetry of the Optical Society of America has defined color as consisting of the characteristics of light other than spatial and temperal inhomogenities, light being that aspect of radiant energy of which a human observer is aware through the visual sensations which arise from the stimulation of the retina”(Ahmed, p.1) Simply stated color is what we “see the result o fthe physical modification of light by colorants as observed by the human eye and interpreted in the brain. Knowing what color is alone is not enoughwe must also understand how we perceive it. The Perception of color depends on many factors such as the inherent color characteristics of an object the surroundings of an object and even by such individual factors like past experience and individual visual response characteristics. (Ahmed p.2) In order to study color one must first learn to describe observed differences in color between two objects. This can be accomplished through the use of the following three variables: hue (dominant color) value (lightness vs. darkness) and chroma (saturation or purity of color). These variables are known as the color coordinates and form the basis of the language system used in color description and specification. (Ahmed p.5)"
On-Line, In-Line and Off-Line Rheometry of Polyethylene
A.L. Kelly, M. Woodhead, R.M. Rose, P.D. Coates, May 1999
In-process rheometry (on-line & in-line) carried out during twin screw extrusion of several polyethylenes (LDPE, LLDPE and three HDPEs) is compared with conventional off-line rheometry for both shear and extensional properties. Use of two on-line and two off-line rheometers allowed comparison of data from a range of commercial instruments in order to validate their performances. In-process shear flow rheometry was undertaken using a six-sensor in-line extrusion die rheometer on a twin screw extruder. Results from the five rheometers were compared and good agreement observed between the different routes to measurement, for these relatively stable materials.
Observation of 3-D Effects in Flow Visualisation of Polymer Melts
P.D. Coates, M. Matsuoka, M. Kamala, M. Martyn, May 1999
Flow visualisation has been undertaken using a specially designed flow cell mounted on a single screw extruder, which permits laser sheet lighting of selected planes in the flow. It has therefore been possible to quantify velocity fields and entry profiles in a 180 degree entry to a slit at locations across the flow, building up, for the first time, a quantified map of velocity components in the axial (x) and transverse (y) flow directions (including at the flow cell wall). Together with stress birefringence measurements, this allows accurate assessment of extensional viscosity, which has been compared with Rheometrics Meissner results for an LDPE. In addition, a modified cell has allowed visualisation of the slit entry region in the third orthogonal direction (z), leading to first ever observations of precession of an LDPE melt in its vortex region, providing new insights into the full 3-d flow field.
Injection Moulding In-Process Measurements of Batch to Batch Variation and Process Variable Influences in Polyamides
P.D. Coates, A.L. Kelly, M. Woodhead, A.J. Dawson, M. Martyn, N. Khoshooee, May 1999
Engineering polymers such as polyamides are known to be process-sensitive. In-process measurement of the flow behaviour of these polymers is therefore preferred over off-line measurements, for reliabilty of the information generated. In line rheometry studies for polyamides on a range of injection moulding machines (including servo electric and servo hydraulic) have been used successfully to monitor and quantify batch to batch variation in commercial polyamides. Specific injection pressure integrals were found to correlate well with product quality assessments. In addition, the effect of moisture content on in-process measurements in polyamides is also being investigated using a design of experiments approach: initial results suggest moisture content has a strong effect on variability of in-process measurements such as specific pressure integrals.
The Composite Sidewalk
Bethany Ashworth, Jeremy Conley, Angelena Newman, May 1999
Plastics affect every aspect of our lives. Plastics is used and discarded everyday. What this theory addresses is how the use of discarded plastic has developed another method to recycle plastics material. Using plastic regrind in composite mixtures not only provides an alternative filler or reinforcement, but it also is a better way to recycle the discarded materials. Taking this theory into consideration, the Shawnee State University Plastics students developed a composite sidewalk using plastic regrind replacing the aggregate in concrete mixtures. The purpose of this paper is to discuss the installation and manufacturing techniques as well as the durability of the sidewalk over the past year.
Determination of Energy of Film Formation for Polystyrene/Poly(Methyl Methacrylate) Latex Blends
K. Michailaros, P. Suwanmala, A. Klein, L.H. Sperling, May 1999
Polystyrene and poly (methyl methacrylate) latexes were prepared using conventional emulsion polymerization. The average diameter of both types of latex particles was close to 60 nanometers with a polydispersity index of 1.05. From the pure latex emulsions, blends were made of polystyrene and poly (methyl methacrylate) mixed according to different weight ratios. Samples of the latex blends as well as samples of both pure polymers were cleaned to remove remaining surfactant and subsequently dried. The dried latex powders were examined in a modulated differential scanning calorimeter so that the energy of film formation could be distinguished from the glass transition. A plot of energy of film formation versus composition shows a distinct minimum occurring at 74-weight % PMMA. The films formed under these conditions had between 10-70% of their surfaces obliterated by interfacial adhesion. A preliminary set of experiments using a high-resolution thermogravimetric analyzer of the latex blends in emulsion form indicates a body centered cubic packing structure for the latex particles.
Effects of Weld Lines on PP and HDPE Tensile Specimens
Valentino Girolamo, May 1999
Preparation of tensile test specimens for polypropylene (PP) and high-density polyethylene (HDPE) was performed according to ASTM Test Designation D5939, Preparing Multipurpose Test Specimens and Bars of Thermoplastics by Injection Molding. Alteration to the mold's runner and cavity gating configurations were made to create or eliminate the presence of weld lines in the finished specimens. Subsequent to specimen production and conditioning, the tensile specimens were tested utilizing ASTM D638, Standard Test Method for Tensile Properties of Plastics. The effect of weld lines for each material was evaluated subsequent to data analysis.
Miscibility of Blends of Thermotropic Liquid Crystalline Polymer and Sulfonated Polystyrene Ionomers
R.A. Weiss, Y. Ghebremeskel, Larry F. Charbonneau, May 1999
The miscibility of a wholly aromatic thermotropic liquid crystalline polyester (LCP) with lightly sulfonated polystyrene ionomers (SPS) was assessed. Zinc salts of an SPS with 5.3 mol% sulfonation were miscible at all compositions with the LCP, but lithium salts with the same sulfonation level formed two phases, a pure LCP phase and an ionomer-rich mixed phase. Zinc salts of an ionomer with 10.8 mole % sulfonation were miscible with the LCP when the blend was richer in the ionomer, but two-phase blends were obtained for LCP-rich compositions. Miscibility in this system arose from intramolecular repulsive interactions along the ionomer chain.
Effect of Processing on Polyaniline Film Anisotrophy
Runqing Ou, Robert Samuels, May 1999
The effect of fabrication process on the structure of two series of oriented PANI base films is examined. The PANI films were previously fabricated from N,N'-dimethyl propylene urea (DMPU) and N-methyl-2-pyrrolidone (NMP) solutions by casting and spin coating procedures. A modified prism waveguide coupling technique was used to measure the birefringence of the visibly opaque PANI films in the near infrared region, while polarized mid-region FTIR was used to obtain their infrared dichroism. The anisotropy developed by the different fabrication and deformation procedures are compared and found to differ.
Aspects of Structure-Property Control for Uniaxially Extruded Stacked Lamellar Polyolefin Films
Matthew B. Johnson, Ta-Hua Yu, Garth L. Wilkes, May 1999
The presentation will focus on the co-authors' investigations concerning the ability to extrude specific polyolefins that result in a well oriented stacked lamellar morphology. These lamellar morphologies serve as potential precursors for developing microporous membranes. Considerations of what criteria are important for the development of the microporous structure in conjunction with the necessary prerequisite of a stacked lamellar precursor will be considered. Examples will draw from the investigator's work on polyethylene, poly-1-butene, and poly-4-methyl-1-pentene. The morphological and mechanical features associated with such extruded films will be highlighted through the use of such techniques as WAXS, AFM, TEM, FTIR dichroism, birefringence, and DMA.
Ultra High Speed Extrusion of Various Polymers
Himanshu R. Sheth, May 1999
In processing most polymers, conventional screws must operate within limited screw speed ranges to avoid overheating. The present study investigates the possibility of ultra high-speed single screw extrusion by incorporating patented Triple Wave design in the metering section of the screw. The study will use a highly instrumented 2.5 50:1 L/D single screw extruder. A modified Taguchi array is used to get an insight into the processing of various polymers. Process parameters such as temperature pressure output and mixing will be investigated. The preliminary results indicate an excellent balance between high output rates temperature buildup and mixing for a range of polymers."
Ultra High Speed Extrusion of Various Polymers
Himanshu R. Sheth, May 1999
In processing most polymers, conventional screws must operate within limited screw speed ranges to avoid overheating. The present study investigates the possibility of ultra high-speed single screw extrusion by incorporating patented Triple Wave design in the metering section of the screw. The study will use a highly instrumented 2.5 50:1 L/D single screw extruder. A modified Taguchi array is used to get an insight into the processing of various polymers. Process parameters such as temperature pressure output and mixing will be investigated. The preliminary results indicate an excellent balance between high output rates temperature buildup and mixing for a range of polymers."
Thermoplastic Pultrusion Based on Isoplast Engineering Thermoplastic Polyurethanes
Ed L. d’Hooghe, Chris M. Edwards, May 1999
Fiber reinforced composite materials are finding application in an ever increasing range of markets. The bulk of the composite materials is based on a thermoset resins combined with glass roving and/or glass mat as continuous reinforcement. Glass filled thermoplastic resins are limited mainly to discontinuous reinforcement and therefore used primarily in injection moulding applications. Despite potential performance and environmental benefits linked to continuous reinforced thermoplastic composites, they have not been implemented on a large scale. This is because they have been lacking performance in comparison to thermoset composites. Thermoplastic composite materials are a class of structural materials waiting to happen, the results booked ??with the process and material described in this paper show that a significant step forward has been made in developing them.
dc Conductivity and Thermopower of Polyaniline Films
K. Eaiprasertsak, R.V. Gregory, G.X. Tessema, May 1999
The dc conductivity (?dc) and the thermopower (S) of doped polyaniline (PANI) emeraldine base (EB) as-cast films were investigated as a function of temperature (T). ?dc(T) ? exp[-(To/T)0.5] is obtained for both types of dopant. Room temperature thermopowers are small <5 µV/K for HCl-doped and CF3SO3H-doped. The thermopower is weakly temperature dependent above 150 K and then undergoes an abrupt increase with decreasing temperature below 150 K. This phase change (?-transition) corresponds to phenyl ring libration. The electrical transport mechanisms for these films are consistent with q-1D VRH obtained from both ?dc(T) and S(T) data.
Structural Implications of Morphology on the Electrical and Mechanical Properties of Inherently Conductive Polymers
Richard V. Gregory, May 1999
Structural morphology defines both the electrical and mechanical properties of inherently conductive organic polymers (ICP). The effect of morphology on the inter-chain charge transport mechanisms, optical and mechanical properties, and stability must be quantified in order to produce fibers and films with segment to segment reproducibility of the desired properties. In this paper we will discuss the effect of solution morphology of fiber and film precursor solutions, as well as the crystallinity and amorphous microstructure in the commercially viable ICP polyaniline (PANI). Structural differences in the emeraldine and leucoemeraldine base forms of this polymer, and the results of these differences on the final electrical and mechanical properties, will be discussed. We will also discuss the recently reported melt transitions observed polyanilines produced from solutions chemically reduced polyaniline
Absorption Correction for Light Scattering of Emeraldine Base Solutions, Part I
S.S. Hardaker, R.V. Gregory, May 1999
Light scattering results from polyaniline emeraldine base solutions in N,N'-dimethylpropyleneurea (DMPU) were carried out at a wavelength of 633 nm. Because emeraldine base absorbs at this wavelength, the results must be corrected. In this paper, the theory of light scattering and the absorption correction are briefly discussed. Also presented are the experimental results of light scattering from dilute emeraldine base / DMPU solutions that have not been corrected, dramatically illustrating the need for absorption corrections. solutions that have not been corrected, dramatically illustrating the need for absorption corrections.
Design Rules for Stereolithography Injection Molding Inserts
Anne Palmer, Jonathan Colton, May 1999
The mold life of stereolithography tooling depends upon factors such as material, processing conditions, and geometrical features. With the establishment of limitations for part geometry, the existing Direct AIM process can become a much more reliable method of producing short runs of functional prototype parts in their end-use material. Draft angle is one factor that contributes to mold life. As the draft angle increases, more parts can be manufactured before failure of the feature. Also, a large gate allows the mold to last longer than a small gate due to the decreased injection velocity.
Effect of Length on the Alignment of Cellulose Microfibrils: A Small Angle Neutron Scattering Study
William J. Orts, D. Louis Godbout, Robert H. Marchessault, Jean-Francois Revol, May 1999
Cellulose microfibrils obtained by the acid hydrolysis of cellulose fibers were aligned in magnetic and shear fields. Small angle neutron scattering, SANS, was used to describe the effect of particle size on alignment. In a 2 Telsa magnetic field, aqueous suspensions of microfibrils exhibit enhanced cholesteric ordering; i.e. the entire sample becomes aligned in a helicoidal, chiral nematic arrangement with the chiral nematic axis aligned in the field direction. In a shear field, cellulose microfibrils align in a simple nematic arrangement, with no evidence of the chiral nematic (cholesteric) packing. The SANS interference peaks indicative of microfibril alignment sharpen with increasing shear rate regardless of the size of microfibrils. Length has a significant effect on the relaxation of enhanced ordering, with longer particles (280 nm in length) remaining remarkably ordered for many hours after cessation of shear, while shorter particles (<180 nm) lose their order within minutes.
.jpg)
.jpg)
.jpg)
.jpg)
