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
Morphology in WPC during Extrusion Foaming with N2
G. Guo, G.M. Rizvi, Y.H. Lee, C.B. Park, May 2006
Incorporating a fine-celled structure in wood-fiber/plastic composites (WPC) foam is important for achieving improved ductility and impact strength. This paper investigates the effects of processing and materials parameters on the morphological changes of WPC during extrusion foaming with N2.
Real-Time Diagnosis for Micro Powder Injection Molding Using Ultrasound
C.-C. Cheng, Y. Ono, B.D. Whiteside, E.C. Brown, C.-K. Jen, P.D. Coates, May 2006
Real-time diagnostics of ceramic powder injection molding with a micromolding machine was performed using ultrasound. Miniature ultrasonic sensors were integrated onto the mold insert. Melt front, solidification and part detachment of the feedstock inside the moldcavity were observed. The assistance of ultrasonic velocity in feedstock inside the mold cavity, the ultrasonic contact time during which the part and mold are in contact and holding pressure may minimize part dimension variation.
Rheology and Thermoforming of Rigid Medical Packaging Materials
A. Costa, G. Zeller, May 2006
Rheological properties were measured on two materials to evaluate their behavior in the thermoforming process. An impact-modified acrylic-based terpolymer compound displayed higher extensional viscosity and melt strength measurements versus a copolyester. The findings in this study showed that lower extensional viscosity and melt strength led to higher molded-in-stress and thinner walls of thermoformed parts.
Influence of Phase Segregation on the Physical Properties of Polyethylene Blends
Rajendra K. Krishnaswamy, May 2006
Phase segregation in melt-extruded blends of polyethylenes that differ considerably in molecular weight was found to exert diverse degrees of influence on various measured physical properties. The instantaneous tensile deformation properties were insensitive to phase segregation while the high-strain tensile deformation behavior is strongly and adversely influenced by phase segregation. Phase segregation of select blend components can favor the plane stress fracture resistance.
Polymer Composites of Modified Carbon Nanofibers Prepared by Chaotic Mixing
Guillermo A. Jimenez, Sadhan C. Jana, May 2006
Surface-modified carbon nanofibers were used using a chaotic mixer to prepare composites of poly (methyl methacrylate). The quality of dispersion, and electrical and thermo-mechanical properties were determined and compared with similar composites containing non-treated carbon nanofibers. Composites of treated nanofibers showed improved dispersion, and better mechanical properties even at high temperatures, but their electrical conductivity was lower than composites of nanofibers without surface treatment.
Increasing the Feasible Bonding Strength in Micro Assembly Injection Molding Using Surface Modifications
Walter Michaeli, Dirk Opfermann, May 2006
Polymers offer a wide range of properties that can be modified according to the needs. An offline joining process can be avoided by overmolding the components to create a hybrid micro system. New research at IKV shows a significant increase in the feasible bonding strength in micro assembly injection molding by using plasma treatment for the inlay parts.
Bead and Fiber Morphologies during Electrospinning of Polystyrene
Goki Eda, Satya Shivkumar, May 2006
The cumulative effects of polymer molecular weight and concentration on the structure of electrospun fibers and beads were investigated. A significant change in fiber diameter and shape was observed as the molecular weight was varied keeping Berry number, [?]C, constant. Below the entanglement concentration, various types of beads including wrinkled beads, cups, dishes and toroids were produced.
Photoviscoelastic Behavior and Residual Thermal Birefringence in Polycarbonates
T.H. Lin, A.I. Isayev, May 2006
The stress-optical coefficient function of two optical grade polycarbonates (PC) has been determined by simultaneous measurements of the relaxation modulus and strain-optical coefficient function. Based on these measurements, linear viscoelastic and photoviscoelastic constitutive equations were applied to evaluate residual thermal birefringence in quenched PC plates. Numerical results have been compared with the measurements.
Characterizing Fiber Diameter and Deformation Using Diffraction Techniques
Peter J. Walsh, Alan J. Lesser, May 2006
A common experimental obstacle encountered during mechanical testing of fibers is that the cross-section area and transverse strain are difficult to assess directly. A laser diffraction technique has been found adequate to measure fiber diameters within the range of 10-100 um during tensile testing with a precision of ±10%. Fiber transverse strain is evaluated by SAXD and used to determine Poisson’s ratio and study deformation at different length scales of fibers with hierarchical structure.
Effect of Plug Design on Thermoformed Polypropylene Parts
Supravan Khongkruaphan, Joey Mead, Stephen Orroth, Noel Tessier, Tom Murray, May 2006
In this study the influence of plug design, namely plug volume, plug taper, plug depth and plug temperature on the wall thickness distribution, weight and compression strength in thermoformed polypropylene cups was investigated. It was observed that the plug volume was the most importance factor for part shape. Plug depth had a significant effect on the bottom and corner thicknesses and part weight. Plug temperature and plug taper had a significant effect only on the compression strength.
Electrospun PVA Fibers as Precursor to Synthesize Hydroxyapatite
Xiaoshu Dai, Satya Shivkumar, May 2006
PVA (Polyvinyl alcohol) with various molecular weights (Mw) were electrospun with a Calcium Phosphate based sol. Fibers on the order of 2 ?m with uniformly distributed sol particles were obtained. Electrospinning process may be facilitated with high molecular weight polymers. The distribution of sol in the electrospun structure may depend on polymer/sol ratio. XRD results indicate that the fibers after calcination consisted predominantly of hydroxyapatite.
Preparation of Polystyrene/Carbon Nanofiber Conductive Composite Film
Chi-Wei Tien, Luyi Sun, Israel Serna, Hung-Jue Sue, May 2006
An efficient and inexpensive approach was developed to prepare conductive polystyrene (PS) films via a simple solution dispersion method. Carbon nanofiber (CNF), which has a similar structure as multiwall carbon nanotubes and a high performance/price ratio, was used as the filler in this research to achieve conductivity in polystyrene films. A good dispersion was achieved within the polystyrene solution system even without using any surfactants. A low percolation threshold at about 0.75wt% has been achieved.
Nano-Clay Tethered Shape Memory Polyurethane Nanocomposites
Feina Cao, Sadhan C. Jana, May 2006
The magnitude of recovery force in shape memory polymers is usually low and must be augmented. In this work, a network is introduced in shape memory thermoplastic polyurethane (PU) by the addition of reactive nanoclay in an effort to improve the recovery force. In this case, nanoclay particles were allowed to tether to PU chains by chemical bonding. This report covers preliminary results on thermal, mechanical, and shape memory properties of clay-PU nanocomposites.
Multivariate Analysis (MVA) for Quality Detection in Injection Molding Systems in the Medical Device Community
Chris Ambrozic, Lee Hutson, May 2006
We describe a new method of point-of-origin quality detection for injection molding systems. The method encompasses data acquisition, Multivariate modeling, reject control and data reporting, provides in-line quality detection of injection molded parts, and real-time reports on fault contributors. We discuss real-world production applications in which MVA is applied using real-time molding parameters to predict quality, with a goal of Parametric Release.
Electrorheological Properties of Carbon Black Filled PDMS
Michael Kaufman, Marianna Kontopoulou, Aristides Docoslis, May 2006
The electrical conductivity and rheological properties under steady shear flow of carbon black-filled PDMS are measured as a function of filler loading, matrix viscosity and shear rate, upon application of an AC electric field. The effects of electric field are most notable at low filler loadings and low matrix viscosities.
Effect of Specimen Thickness on PC/ABS Spiral Flow Injection Moldings
N. O-Charoen, S. Pivsa-Art, Y.W. Leong, K. Umemura, M. Kotaki, H. Hamada, May 2006
The morphology of PC/ABS blend injection moldings is investigated using a spiral flow test mold. The results show that the specimen thickness would significantly affect the internal structure. Effect of specimen thickness on morphology of dispersed ABS phase in skin and core layers is extensively discussed in the relation to the mechanical properties.
Visualization of PP Foaming with Nitrogen
Q. Guo, J. Wang, C.B. Park, May 2006
In this research, we observed the cell nucleation and initial growth behaviours of PP foaming with N2 under various experimental conditions in a batch foaming simulation system. We found that the nucleating agent content, initial temperature, initial pressure (i.e., gas content), and pressure drop rate during foaming had significant effects on cell density and cell growth. The branched PP (WB130)/N2 had a higher cell density than the linear PP (HE351)/N2.
PP Melt Swelling Due to Gas Dissolution
Y.G. Li, H.B. Li, J. Wang, C.B. Park, May 2006
Foaming of thermoplastic is gaining interest because of its potential to decrease the weight of automotive parts. Understanding of the thermophysical properties of PP/gas mixtures is critically important in this context. This paper presents a newly developed experimental technique that captures the melt pendent drop images locally, determines the boundary locations precisely and then reconstructs those images to accurately measure the swelling of the polymer due to gas dissolution at elevated temperatures and pressures.
Pressure Profile in Annular Die Using PP/CO2 Solution Viscosity
Jing Wang, Chul B. Park, May 2006
In this paper, a rheological die with a slit channel was designed to determine the solution viscosity of supercritical CO2 in non-crosslinked high-melt-strength (HMS) polypropylene (PP). The shear viscosity was modeled as a function of temperature, pressure, gas content, and shear rate. With interest in producing highly expanded foam sheets using an annular die, an analysis of the annular die pressure profile using the measured viscosity data was also conducted.
Fine-Celled Foaming of HDPE Using Nitrogen
J.W.S. Lee, C.B. Park, May 2006
Foaming experiments were performed in extrusion using HDPE and Nitrogen. Talc was used as a nucleating agent, and three levels of pressure drop rate were applied. The use of talc significantly increased the cell density and reduced the role of pressure drop rate in cell nucleation.
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