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

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.

Ultra High Molecular Weight Siloxane Additives in Polymers - Effects on Processing and Properties
Kevin J. Ryan, Kevin E. Lupton, Peter G. Pape, Vivian B. John, May 1999

Two new types of solid siloxane additives for plastics are described which give improved benefits compared to previous silicone additives. Ultra high molecular weight siloxanes are used in the new additives; traditional silicone plastic additives have used much lower molecular weight silicones. The siloxane is converted into solid forms, either masterbatch pellets or powders, that are easy to feed, or mix, into plastics during compounding, extrusion, or injection molding. Ultra high molecular weight siloxanes can be compounded into masterbatch pellets at higher siloxane concentrations (50%) than previously possible. They impart improved processing, release, lower coefficient of friction, and broader performance latitude compared to conventional lower molecular weight silicones. A new functionalized UHMW siloxane has been developed which has been found to provide unique surface segregation characteristics. Ultra high molecular weight siloxanes have been formulated into powders that can also act as processing aids and mechanical property modifiers. This paper will use polyolefins as a model. However, many of the effects shown in polyolefins have also been seen in other resin systems.

Dyes in PET: A Look at FDA Compliance Issues
Tracy Phillips, Ralph A. Helfer, May 1999

The use of articles in food-contact applications involves both regulatory and scientific considerations where establishing the status of the individual product ingredients or components under the laws and regulations administered by the Food and Drug Administration (FDA) is required. This paper will focus on these considerations by discussing the definition of food additive, FDA's regulatory framework for substances used in food contact articles, and general requirements for testing the materials to establish their appropriate FDA status. This paper will also present a general overview of the data necessary for supporting a Food Additive Petition submitted to FDA to clear a new food-contact material or product such as dyes in PET.

Trends in Automotive Plastics
Norm Kakarala, May 1999

This briefing on trends in automotive plastics will delineate the differences in plastics application areas between North American and overseas markets. The key themes addressed include: • Although mass savings are widely thought to be a key driver in metal replacement by plastics, increasingly automakers are more interested in the contribution of plastics to styling, occupant safety and comfort, and functionality. • Plastics are increasingly specified for their design freedom. They make possible the consolidation of parts and consolidation of functions, minimizing manufacturing costs while maximizing function and value. • Competition among automotive plastics is relentless and intensifying, resulting in improved forecasted growth for some plastics at the expense of others. • Plastics application trends will be compared between North America and overseas in four sectors: Interiors, Exteriors, Under the Hood, and Chassis and Powertrain. • Greater attention is being given to polymer composites in the U. S. for exterior body panels and some structural applications, with minimal interest in other countries. • Finally, more progress is being made in the recycling of plastic manufacturing scrap than in the recycling of plastic parts/materials from scrap vehicles. This is so because manufacturers have control over process scrap, which improves recyclability and the value of recycled materials. The use of plastics in vehicles is steadily increasing. This trend is expected to continue. On average, current vehicles use about 113 Kg (250 Lbs) of plastics and that amount is estimated to grow to 137 kg (300 Lbs) per vehicle in the next ten years. Historically, vehicle weight savings has been a primary driver in replacing metals with plastics on vehicles. However, today styling, end-use functionality, and better manufacturing economics through parts consolidation are the key factors in choosing plastics to replace other materials in vehicle applications. In addition, fut

Investigation of the Crystallinity of a Hindered Phenolic Antioxidant by Differential Scanning Calorimetry
Robert E. Lee, Subramaniam Narayan, Luciano Pallini, John M. Zenner, May 1999

The effectiveness of polymer stabilizers has allowed polymers of all types to be used in increasingly critical applications. The performance of these additives is not only determined by the chemical efficacy of the molecule, but also by the ease with which it can be incorporated into the polymeric material in need of stabilization. Compounds which exist in several discrete crystalline or amorphous physical forms may behave in a profoundly different manner in terms of melting points and rates of dissolution.. Octadecyl 3-(3',5'-di-t-butyl-4'-hydroxy-phenyl) propionate (AO1) behaves in just this manner. Our investigation of the various crystal forms as well as an amorphous state demonstrate the care which needs to be taken to ensure that the optimum physical form is obtained.

Filled and Reinforced Aliphatic Polyketone Compounds
Gingrich R P | Machado J M | Londa M | Proctor M G, May 1995

A major portion of engineering thermoplastic materials is utilized in the form of compounds containing a high loading of inorganic materials. The inorganic components may perform a variety of useful functions such as the reduction of compounds cost or the increase in stiffness, strength, dimensional stability, or heat resistance of the finished part. Aliphatic polyketones can be compounded with inorganic fillers and reinforcing agents resulting in benefits similar to those found in other thermoplastics. A discussion of the mechanical properties of compounds containing several types of fillers, classified according to chemical type and particle shape, will be presented.

Determining Apparent Melt Viscosity by Cavity Pressure
S. Horváth | A. Szücs

The online measurement of the viscosity of the polymer melt may contribute to the production of excellent products. The supervisory system of injection molding machines can only provide limited feedback on the processes in the cavity, therefore measuring the pressure in the mold contributes to the supervision of quality. The goal of our research is to gain more knowledge about the filling process and to determine the apparent viscosity of the material in the filling phase. For the research eight pressure sensors per cavity were built into an experimental specimen mold. Varying the wall thickness, the apparent viscosity was determined at different melt speeds. In the filling phase, non-isothermal and non-adiabatic flow were examined, they were considerably different from the environment of standard measuring equipment. The results were validated with a Göttfert capillary rheometer. They showed good agreement in a certain speed range and wall thickness when PP was used.

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