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
STRESS-STRAIN BEHAVIOR OF EXPANDED POLYMER COMPOSITES AT ELEVATED TEMPERATURES
Katherine M.H. Shipley, K. Jayaraman, K.L. Nichols, May 2012
Stress-?strain curves under uniaxial tension have been evaluated at temperatures ranging from room temperature to 145 C for glass bead filled polypropylene, glass flake filled polypropylene and unfilled polypropylene. Debonding of the fillers in the elastic regime leads to growing voids in the composites, which affects the yield point and the plastic deformation of the expanded composites. Models were fitted to the elastic and plastic regimes of deformation in the various materials at different temperatures.
EXPERIMENTS WITH CONVENTIONAL AND HIGH TEMPERATURE HOT PLATE WELDING OF THERMOPLASTICS USING DISPLACEMENT AND PRESSURE CONTROL
Abbass Mokhtarzadeh, Avraham Benatar, May 2012
During hot plate welding, the final forging phase can be controlled by either pressure or displacement. When using pressure control, the parts are placed under constant pressure thereby simultaneously squeezing and cooling the melt until the interface solidifies. In displacement control, the parts are pressed together until mechanical stops are reached and the weld cools further under no pressure. In this work, we studied contact hot plate welding of high HDPE and ABS using low and high temperature hot plate with both pressure and displacement control. For HDPE, the weld strength was high regardless of the hot plate temperature or control method. For ABS high temperature hot plate welding produced stronger joints for both control methods.
ENVIRONMENTAL AGING OF COATED FABRICS COMPOSITES
James M. Sloan, D. Flanagan, C. Pergantis, P. Touchet, H. Feuer, May 2012
The purpose of this work was to perform a comparative analysis of various candidate nitrile coated fabric materials supplied by potential vendors to be used as fuel storage tanks and compare the results to the currently fielded polyurethane storage tanks. Our strategy is to utilize advanced environmental ageing methods to simulate extended weathering conditions. Our results demonstrate that the nitrile coated fabrics performed well in our evaluation. Their breaking strengths are about equal to the currently fielded urethanes and they performed comparably when subjected to environmental ageing conditions.
COMPUTER SIMULATION OF RUBBER EXTRUSION IN THE CAPILLARY DIE USING VISCOELASTIC MODELS
J. H. Kim, Hyuk Kim, M.-Y. Lyu, S. H. Choi, H. J. Kim, May 2012
Rubber compounds have high viscoelastic property. The viscoelastic behaviors shown in die extrusion are an extrudate swell and circulation flow at the entrance of die. Application of viscoelastic models to a capillary extrusion has been investigated in this study. Experiment and simulation have been performed using fluidity tester and commercial CFD code, Polyflow respectively. Die swells of rubber compounds through a capillary die have been predicted using various viscoelastic models, such as PTT, Giesekus, and POMPOM models. Simulation results of die swell were compared with the experiment. Pressure drops, velocity distributions and circulation flows at the corner of reservoir have been analyzed through computer simulations.
MECHANICAL PROPERTIES OF SULFONATED BLOCK COPOLYMERS
J. M. Sloan, E Napadensky, D Suleiman, May 2012
Dynamic mechanical analysis (DMA), and FT-IR was used to examine a series of highly sulfonated poly(styrene- isobutylene-styrene) (SIBS) block copolymers. Sulfonation levels of 53%, 64% and 97% were studied. These block copolymers were subsequently neutralized with three inorganic counter-ions, Mg2+, Ca2+ and Ba2+. The substitution of inorganic counter-ions maintained the glass transition temperature of the membrane at -60°C regardless of cation exchanged and increased the modulus of the rubbery plateau indicative of a crosslinking complex formation. New relaxations were observed above Tg for the highly sulfonated counter-ion substituted samples attributed to the Tg of the functionalized styrene segments. FT-IR results show a shifting of the IR bands attributed to the sulfonate groups when counter-ions are added, indicating the formation chemical crosslinks.
RHEOLOGICAL PROPERTIES AND FOAMING BEHAVIOR OF COAGENT-MODIFIED POLYPROPYLENE
Ying Zhang, Marianna Kontopoulou, J.Scott Parent, Savvas G. Hatzikiriakos, Chul B. Park, May 2012
Reactive modification of linear PP by radical mediated grafting in the melt state is investigated as a means of increasing its melt strength, thus resulting in improved foam processing characteristics. A tri-functional coagent, triallyl trimesate (TAM) is used to introduce long chain branching to the linear PP homopolymer. Rheological characterization is conducted to relate the rheological properties to the modified PP chain architecture. The foaming behaviour of the linear and branched PPs is investigated using a batch foaming apparatus with N2 as a blowing agent.
NUMERICAL VERIFICATION OF RHEOLOGICAL CHARACTERIZATION OF POLYSTYRENE DURING MICROCELLULAR INJECTION MOLDING
Shia-Chung Chen, Kuan-Hua Lee, Yu-Wan Lin, Tai-Yi Shiu, Chuan-Wei Chang, Jimmy C. Chien, May 2012
The purpose of this study is to investigate the rheological behavior of Polystyrene melt with dissolved SCF of nitrogen during Microcellular Injection Molding process applied with Gas Counter Pressure (GCP) technology; also, rheological behavior is compared with independent theoretical simulation using moldex3D. A slit cavity is designed to measure the pressure drop of polystyrene mixed with 0.4wt% supercritical nitrogen fluid under different mould temperatures (185°C, 195°C, and 205°C), injection speeds (5, 10, and 15 mm/s) as well as counter pressures (0, 150, 300 bars). It was found that the melt viscosity is reduced by up to 30% when GCP is increased from 50 to 150 bar as compared to conventional injection molding. The simulation results of pressure history well agrees with the experiments and provide a theoretical point of view on process design.
MEASUREMENT AND MODELING OF PLANAR AND UNIAXIAL EXTENSIONAL VISCOSITIES FOR LDPE POLYMER MELT
Martin Zatlouka, May 2012
In this work, novel patent pending rectangle and circular orifice dies have been used in order to determine planar and uniaxial extensional viscosities for extrusion coating LDPE through entrance pressure drop determination on conventional twin bore capillary rheometr. It has been revealed that the uniaxial extensional viscosity/uniaxial extensional strain hardening is higher in comparison with the planar extensional viscosity and recently proposed non-Newtonian fluid model can described the measured rheological data reasonably well.
ANTIMONY TRIOXIDE-FREE FLAME RETARDANT SYSTEMS FOR POLYMERIC MATERIALS
Subramaniam Narayan, Marshall Moore, May 2012
Flame retardants in polymers play a significant role in protecting lives and reducing damage in the event of a fire. Typically brominated flame retardants (BFR) require a synergist such as antimony trioxide (ATO) that enables lower loadings of the BFR in polymer formulations. However for compliance to certain voluntary environmental standards, it is desirable to replace ATO partially or completely in polymer formulations. This work describes the replacement of ATO in formulations containing a newly developed flame retardant, Emerald 1000 (FR1). In high impact polystyrene (HIPS), FR1 is shown to exhibit good flame retardancy when combined with a char forming polymer like polyphenylene ether (PPE). Similarly in polycarbonate (PC)/acrylonitrile butadiene styrene (ABS) systems, FR1 shows good flame retardancy, without the need for ATO synergist. More importantly FR1 does not negatively impact the mechanical properties of the system.
HIGH-SHEAR-RATE RHEOLOGY OF POLYSTYRENE MELTS
Wei Sheng Guan, Han Xiong Huang, May 2012
This work presents a systematic analysis on the capillary rheology of polystyrene melts under high shear rates ranging from 103 to 106 s-1. The precise Bagley correction was achieved by means of the enhanced exit pressure technique. The end pressure drop was found to predominate over the Bagley-corrected capillary pressure drop in the high shear rate range. Furthermore, the dissipation heating, pressure dependence, and compressibility effects were quantitatively evaluated. Results implied that the apparent nonlinearity of the Bagley-corrected capillary pressure drop versus apparent shear rate profile, which occurred at the shear rates of above 105 s-1, mainly resulted from the dissipation heating. In the shear rate ranges investigated, the corrected rheological behavior could be adequately described by the power law.
PREPERATION AND CHARACTERIZATION OF PP-PET SEA-ISLANDS TYPE BICOMPONENT AS-SPUN FIBERS BY HIGH-SPEED MELT SPINNING
Joo-Hawn Yoo, Wan-Gyu Hamn, May 2012
In this study, to investigate characteristic fiber deformation behaviors in high-speed melt spinning process of sea-islands type bicomponent fiber, high-speed melt spinning for PP-PET sea-islands type bicomponent fiber was conducted upto 7 km/min. Overall diameter profiles from nozzle to winder for single- and bi-component fibers could be obtained through on-line measurement of diameter. Structure evolution of obtained as-spun fibers was systematically investigated by using 2D WAXD, DSC, birefringence, and tensile test etc.
MONITORING OF THERMAL HOMOGENEITY IN SINGLE SCREW EXTRUSION USING INFRARED TEMPERATURE SENSORS
Javier Vera Sorroche, Elaine Brown, Adrian Kelly, Phil Coates, May 2012
The ability of infrared temperature sensors to provide information relating to the thermal homogeneity and melting performance of single screw extruders has been investigated. Infrared sensors were located in the barrel of a single screw extruder close to the end of the screw and in an instrumented die adaptor. Results were compared to those obtained from a thermocouple grid sensor located at the entrance to the extruder die. Two grades of high density polyethylene were used in experiments with three extruder screw geometries at a range of screw speeds. When located in the die adaptor, the infrared sensor detected temperature fluctuations related to melting instabilities but these were smaller in magnitude than the actual fluctuations detected by the thermocouple grid sensor due to the limited penetration depth of the infrared sensor. When located in the extruder barrel the infrared sensor provided a bulk measurement of melt temperature across the depth of the screw channel in the metering section which correlated more closely with that measured using the thermocouple grid.
COMPUTER SIMULATION OF FLOW BALANCE IN THE DIE OF SLOT COATER: PART 1: LAND GEOMETRY
Hyun Kim, Yohan Park, Jinsoo Hong, M.Y. Lyu, S.K. Shin, J.K. Seo, May 2012
Coating operations such as spin coating, curtain coating, role coating, slide coating, slot coating, and etc. are dated from long time ago and still considered very important processing. Slot coating is considered very important specially for the manufacturing of liquid crystal display parts. Photo resistant is coated on the glass and is sent to next process to make TFT board. Coating quality such as uniformity of coating thickness can be divided into two categories, which are machine direction quality and transverse direction quality. Machine direction quality is related to die lip design and operation conditions whereas the transverse direction quality is related to flow uniformity inside of the die. The flow uniformity is governed by flow balance in the die. The most important design factors for the inside die geometry are manifold and land. Through this study the flow balance according to the land design has been examined by computer simulation. The parameters for land design are length and shape. Exit velocity at the outlet of die is different from land designs. The best land design has been investigated in this study.
SUPERCRITICAL FLUID DOSAGE CONTROL USING ARTIFICIAL NEURAL NETWORK (ANN) FOR MICROCELLULAR INJECTION MOLDING
Xiaofei Sun, Lih-Sheng Turng, Patrick J. Gorton, Eugene P. Dougherty Jr, May 2012
Supercritical fluid (SCF) dosage is one of the most important parameters for microcellular injection molding. Highly accurate and repeatable SCF dosage is required to ensure high part quality and consistency. In this study, an artificial neural network (ANN) based SCF dosage control strategy was proposed to predict and compensate for the possible variations in the coming SCF dosing stage to achieve a more repeatable SCF dosage. The result shows that this control strategy can be successfully implemented, and that it leads to significant improvements in dosage consistency and part quality.
PULL AND FOAM - INJECTION MOULDING METHOD: FOAMED RIBS FOR STIFFENING PLANE COMPONENTS
Hans-Peter Heim, Mike Tromm, Stefan Jarka, Joachim Schnieders, Stefan Gövert, May 2012
The pull and foam method is a foam injection moulding method which introduces the possibility to partially foam a component. In this way, thin-walled, hardly foamed components with foamed ribs can be made in one processing step, thus also components with graded properties. One the one hand this components possess a high stiffness, one the other hand a high surface quality. The method introduces the advantages of foam injection moulding procedure to new application fields.
COMPATIBLIZED POLYPHENYLENE SULFIDE/LIQUID CRYSTAL POLYMER ALLOY FOR ELECTRICAL&ELECTRONIC APPLICATIONS
Rong Luo, Xinyu F. Zhao, May 2012
The combination of polyphenylene sulfide (PPS) and liquid crystal polymer (LCP) in polymer blend is a potential way of creating new polymer properties. However, the two polymers are incompatible, and typical physical blends do not realize synergistic performance. Herein we report a compatiblized PPS/LCP alloy. Morphology and thermal analysis confirm the improved compatibility of PPS and LCP. As a result, mechanical properties of the compatiblized PPS/LCP alloy are improved. In particular, the notched Izod impact improves by 45% and weld line strength improves by 37% compared to PPS/LCP physical blend. The surface quality as measured by surface gloss of the compatiblized alloy is also improved significantly. In addition, the compatiblized PPS/LCP alloy is halogen free according to IEC 61249-2-21 standard and meets V-0 flammability of the UL-94 standard. Such compatiblized PPS/LCP alloy is an ideal material for electronics applications such as connectors and printer parts.
ULTRA-HIGH THERMALLY TREATED LLDPE NANOCOMPOSITES: TRANSPORT PROPERTIES AND ELECTROMAGNETIC SHIELDING
Byron Villacorta, Amod A. Ogale, Todd Hubing, May 2012
The electromagnetic shielding effectiveness (EM SE) and the electrical properties of ultra-high thermally treated carbon nanotubes/nanofibers in LLDPE matrix were evaluated. EM SE displayed dependence on electrical resistivity and electrical permittivity. Nanocomposites at 60wt% nanomodifier content showed EM SE values as high as 67 dB at 1.5GHz. The primary shielding mechanism in these nanocomposites was absorption. Therefore, such nanomaterials have potential use in electromagnetic compatibility applications.
PROGRESS ON SIMULATING LONG-GLASS FIBER ORIENTATION IN COMPLEX MOLDING GEOMETRIES
Kevin J. Meyer, Donald G. Baird, May 2012
The mechanical properties of fiber reinforced materials are highly dependent on fiber orientation generated within the composite during molding operations. Rheologically obtained parameters for fiber suspensions are applied to current models to predict fiber orientation in complex geometries independent of experimental considerations. This method provides an a priori pathway to determine fiber orientation based solely on rheological testing of the suspension and independent of the mold geometry. Furthermore, predictions for fiber orientation are carried out using the traditional rigid fiber Folgar-Tucker model as well as the semi-flexible Bead-Rod model which allows for the inclusion of fiber bending to be taken into account often witnessed in long-glass fiber (LGF) systems. Computations for fiber orientation are performed for center-gated disks and predictions with the two above models are compared to experimental data.
HIGH PERFORMANCE METALLOCENE POLYETHYLENE BASED ON SK INNOVATION’S NEXLENE™ TECHNOLOGY
Sewon Oh, Seungbum Kwon, Hyeongtack Ham, Sungseok Cha, May 2012
SK innovation has developed a new polyethylene technology, Nexlene™, capable of producing from mPOE to mHDPE based on SK’s novel metallocene catalyst. The process technology is based on a solution process and therefore is capable of producing octene-1 copolymers. Additionally, the bimodal process allows for product tailoring via adjusting the molecular weight distribution and co-monomer distribution. So we can obtain high performance Nexlene™ products with superior general physical properties, transparency, processibility, and organoleptic properties.
A NOVEL METHOD TO PREPARE PET NANOCOMPOSITES BY WATER-ASSISTED MELT COMPOUNDING
Maryam Dini, Pierre J. Carreau, Tahereh Mousavand, Musa R. Kamal, Minh-Tan Ton - That, May 2012
Polyethylene terephthalate (PET) nanocomposites were prepared via melt compounding of PET using a twin screw extruder. Water was fed to the extruder to assist in intercalation/exfoliation. The ratio between the water and PET feed rates was varied and Cloisite Na+, Cloisite 30B and Nanomer I.238E were used. Wide angle x-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and rheometry were used to characterize the PET nanocomposites.
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