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
INVESTIGATION OF COMPARITIVE STRESS DISTRIBUTIONS IN THERMOFORMING VERSUS INJECTION MOLDING
Thomas W. Shoaf, May 2010
The comparison of stress distributions has been investigated in thermoformed and injection molded parts of a similar design. Injection molding is traditionally preferred for automotive applications because of its ability to create parts with minimal internal stress. However in recent years because of potential cost reductions thermoformed parts are often being substituted. Matrox Inspector has been used to evaluate internal stress created by both processes. Results show a difference in the comparative stress distributions of similar parts that is dependent on location.
LOW TEMPERATURE CURE KINETICS OF VINYL ESTER AND UNSATURATED POLYESTER/CARBON NANOFIBER NANOCOMPOSITES
Siva Movva, Jose M Castro, L. James Lee, May 2010
Unsaturated polyester (UP) and vinyl ester (VE) resins are two of the most widely used thermoset resins in fiber reinforced composites due to their low cost and good processability. Adding nanoparticles like carbon nanofibers (CNFs) as a third phase into conventional composites results in hybrid nanocomposites with improved mechanical properties and multi-functionalities, and at the same time makes the curing reaction even more complex. In this paper, the effects of CNFs on the reaction kinetics of the two free radical polymerization systems are studied. VE/CNF kinetics is presented in more detail including interesting interactions between CNFs and curing ingredients in the system. Preliminary reaction kinetics data of UP/CNF is also presented.
VISUALIZATION STUDY ON THE FILLING PROCESS OF PS/SC-CO2 DURING MICROCELLULAR INJECTION MOLDING
Jian-Kang Wang , Xiang-Yang Liu , Han-Xiong Huang, May 2010
Microcellular injection molding attracts more and more interests in industry because of its advantages, such as weight reduction, energy saving, cycle time reduction, etc.. In order to investigate the filling process of microcellular injection molding, a visual mold was developed in this work. The filling processes of polystyrene/carbon dioxide was observed and recorded using a digital camera, while the mold cavity pressure was measured by a sensor. The final bubble morphology was observed using scanning electron microscope. The experiment results showed that melt temperature and mold cavity pressure were two most prominent factors influencing bubble morphology.
STRUCTURE AND PRPERTIES OF MELT-SPUN PET/MWCNT NANOCOMPOSITE FIBERS
Saeedeh Mazinani , Abdellah Ajji , Charles Dubois, May 2010
The structure and properties of polyethylene terephthalate (PET)/multi-wall carbon nanotube (MWCNT) fibers were investigated in this work. PET/MWCNT nanocomposite was obtained through melt mixing and CNT masterbatch dilution into desirable concentration. PET/CNT nanocomposite was then shaped to microfibers at different CNT concentrations and drawing conditions. The dispersion and distribution of CNT were optimized and the effect of processing condition on the morphology of nanocomposite was investigated by various microscopy techniques. Through the dispersion optimization, conductive fibers were obtained at 2% concentration of MWCNT. The study of crystalline structure of the fibers shows the role of CNT addition on enhancement of crystallinity in rod-like fibers; while in drawn fibers, it causes decrease in both the crystallinity and orientation during melt-spinning. Fiber production enhances the electrical conductivity along fiber axis. In addition, the increase in crystallinity by adding CNT shifts the mechanical properties to quite brittle behavior.
EFFECTS OF FREE SURFACE AND SUBSTRATE INTERACTIONS ON THE DISTRIBUTION OF GLASS TRANSITION TEMPERATURES IN NANOCONFINED POLYMERS
Hui Deng , John M. Torkelson, May 2010
A fluorescence/multilayer technique was used to determine the distribution of glass transition temperatures (Tgs) in nanoconfined poly(methyl methacrylate) films. Poly(methyl methacrylate) exhibits an attraction to silica shown by an increase in Tg near the substrate. Perturbations in dynamics associated with Tg near a free surface lead to a Tg decrease. Both effects are shown to penetrate some tens of nanometers into a nanoconfined film. Effects of nanoconfinement on the transition between free-surface bulk and substrate Tg are explored with potential application to nanocomposite behavior.
EFFECTS OF FREE SURFACE AND SUBSTRATE INTERACTIONS ON THE DISTRIBUTION OF GLASS TRANSITION TEMPERATURES IN NANOCONFINED POLYMERS
Hui Deng , John M. Torkelson, May 2010
A fluorescence/multilayer technique was used to determine the distribution of glass transition temperatures (Tgs) in nanoconfined poly(methyl methacrylate) films. Poly(methyl methacrylate) exhibits an attraction to silica, shown by an increase in Tg near the substrate. Perturbations in dynamics associated with Tg near a free surface lead to a Tg decrease. Both effects are shown to penetrate some tens of nanometers into a nanoconfined film. Effects of nanoconfinement on the transition between free-surface, bulk, and substrate Tg are explored, with potential application to nanocomposite behavior.
CHARACTERISATION OF DENSIFICATION TEMPERATURE IN ROTATIONAL MOULDING
P.R.W. Hanna , E. Maziers , M.P. Kearns , M. McCourt , G.M. McNally, May 2010
The temperature at which densification ends for a range of blends comprising a metallocene catalysed medium density polyethylene (PE) in two different physical forms (powder and micropellets) were investigated using a novel data acquisition system (TP Picture??) developed by TotalPetrochemicals [1]. The various blends were subsequentlyrotomoulded and test specimens prepared for mechanical analysis to establish the relationship between densification rate and bubble size / distribution on the part properties.The micropellets exhibited more rapid bubble removal times than powder.
EFFECT OF SURFACE MODIFIED MULTI-WALLED CARBON NANOTUBES ON THE LOW TEMPERATURE CURE KINETICS OF WIND BLADE EPOXY SYSTEM
M. Ponting1, D.S.Langhe, A. Hiltner, E. Baer, D.R.Paul, May 2010
The effect of multi-walled carbon nanotubes (MWNTs) on the curing kinetics of wind blade epoxy resin system was investigated. Isothermal differential scanning calorimetry technique was used to study the reaction kinetics. A comparison was made between the effect of pristine nanotubes and surface functionalized nanotubes on the epoxy polymerization kinetics. It was found that the curing reaction could be accelerated and resin conversion at room temperature could be increased using appropriate surface functionalization. This could find useful application in reducing the composite manufacturing times for large parts like wind blades.
EFFECT OF FORCED ASSEMBLY NANOLAYERING ON THE PHYSICAL AGING OF POLYSULFONE FILMS
M. Ponting , D.S.Langhe , A. Hiltner , E. Baer , D.R.Paul, May 2010
The effect of layer thickness on the physical aging of nanolayered glassy polysulfone (PSF) against a rubbery random copolymer ethylene octene (EO) layer was investigated via forced assembly coextrusion. A post-extrusion thermal treatment above the Tg of polysulfone was developed to allow for a reset physical aging process. Physical aging of thermally reset polysulfone/ethylene-octene nanolayered films was performed and monitored through a thermal aging under elevated temperatures. The relationship of layer thickness to polysulfone physical aging was investigated through thermal analysis microscopy and positron annihilation spectroscopy.
EFFECTS OF NYLON6 NANOCOMPOSITES WITH NANOCLAY QUANTITY ON PART MOLDABILITY OF IN MOLD DECORATION MOLDING
S.H. Masood, M. Nikzad, Vishal Patel, May 2010
Nylon6 nanocomposites (with2.0 wt% and 4.0 wt% nanoclay-montmorillonite) and two kinds of PC film with thickness of 0.125 mm and 0.175 mm combined varied ink formulas were used to investigate the effect of nanoclay quantity on ink washout of in mold decoration molding (square plate specimen with thickness of 2.0mm). It was found that Nylon6 nanocomposites with nanoclay quantity of 4.0wt% would increase 30% washout area than of 2.0wt% addition quantity. In addition, higher injection speed would increase shear stress leading to large ink washout area whereas higher melt temperature would decrease ink washout area.
MELT FLOW ANALYSIS OF ABS IN FUSED DEPOSITION MODELLING PROCESS
S.H. Masood , M. Nikzad , Vishal Patel, May 2010
This paper presents a numerical study of melt flow behaviour of ABS plastic through the melt flow tube of the liquefier head of the Fused Deposition Modelling (FDM) rapid prototyping process using the finite element analysis. Main flow parameters including temperature, velocity and pressure drop have been investigated. Liquefier head of FDM machine has been modelled parametrically and the effects of physical modifications including nozzle angle variation on the melt flow parameters have been investigated accordingly. Results provide promising information on flow behaviour of new ABS based composites for processing in the FDM system to fabricate new products.
POLYSTYRENE MONTMORILLONITE NANOCOMPOSITE MICROCELLULAR FOAM USING SUPERCRITICAL CARBON DIOXIDE AS BLOWING AGENT
Babu Padmanabhan, Chetan Chincholi Jayanth, May 2010
Exfoliated organoclay in the polystyrene-block-poly(2-vinyl pyridine) was used the as a model material for investigating the heterogeneous nucleation effect of nanoclay in polymer foams. Using strictly controlled foaming process, the experimental results indicate that exfoliated clay in polymer matrix is able to decrease the cell size and increase the cell density. The cell size can be reduced to about 1.4 ?¬m and the cell density increase to 8.4*1010 cells/cm3 when 20 wt.% of organoclay was added. On the contrary, aggregated nanoclay has no effect on the cell size and cell density.
SPECIAL INTAKE ELEMENTS TO OVERCOME FEED LIMITATION IN COROTATING TWIN-SCREW EXTRUDERS -DESIGN FEATURES AND EXPERIMENTAL RESULTS
Babu Padmanabhan , Chetan Chincholi Jayanth, May 2010
Forced and starve feeding are well known feeding methods to input material into a co-rotating twin screw extruder. Polymers in powder form and materials such as talc and mica are a challenge to introduce into the extruder. The geometry of the intake zone screw elements and the side-feed zone screw elements decide the conveying ability and the intake capacity of the extruder. The problem of lower intake capacity is solved by the use of Single Flight Shovel (SFV) Triple Flight Shovel (TFV) and Regular Flight Shovel (RFV) classified as 'FV' type elements (Patent Pending). The screw flights are designed to plough through the material similar to the working of a snowplough. Increase in intake capacity compared to Erdmenger-type and Schubkanten-type screw elements is discussed.
SPECIAL INTAKE ELEMENTS TO OVERCOME FEED LIMITATION IN COROTATING TWIN-SCREW EXTRUDERS -DESIGN FEATURES AND EXPERIMENTAL RESULTS
Babu Padmanabhan , Chetan Chincholi Jayanth, May 2010
Forced and starve feeding are well known feeding methods to input material into a co-rotating twin screw extruder. Polymers in powder form and materials such as talc and mica are a challenge to introduce into the extruder. The geometry of the intake zone screw elements and the side-feed zone screw elements decide the conveying ability and the intake capacity of the extruder. The problem of lower intake capacity is solved by the use of Single Flight Shovel (SFV), Triple Flight Shovel (TFV) and Regular Flight Shovel (RFV) classified as 'FV' type elements (Patent Pending). The screw flights are designed to plough through the material similar to the working of a snowplough. Increase in intake capacity compared to Erdmenger-type and Schubkanten-type screw elements is discussed.
3D SIMULATIONS OF A REACTIVE FLOW IN SCREW ELEMENTS OF CLOSELY INTERMESHING TWIN SCREW EXTRUDERS: CONVENTIONAL AND VARIABLE SPEED EXTRUDERS
Babu Padmanabhan, Chetan Chincholi Jayanth, May 2010
The peroxide-initiated degradation of polypropylene in conveying screw elements of closely intermeshing twin screw extruders (COITSEs) is analyzed by means of a three-dimensional (3D) simulation approach. The simulations are implemented for a conventional and a special design screw element (from a variable speed extruder). Different values of peroxide concentrations and mass throughputs are implemented to analyze the reactive system of interest in terms of the specified extruder design.
SHEAR UNIFORMITY IN CO-ROTATING TWIN SCREW EXTRUDER - A GEOMETRICAL STUDY OF SHEAR RATES IN A FULLY FILLED ZONE
Babu Padmanabhan , Chetan Chincholi Jayanth, May 2010
Increase in screw speed results in increased localized shear rates in co-rotating twin-screw extruders due to higher radial and meta-radial shear. This results in shear non-uniformity which in-turn results in degradation of shear sensitive material. Shear rates induced by kneading elements with different geometries are studied in the axial (longitudinal) radial and meta-radial shear planes. Elements with fractional lobed geometry having unequal tip angles show greater shear uniformity minimizing excessive shear in small regions. A careful study of the geometries of kneading elements and their shear distribution is provided for practical use in compounding application.
SHEAR UNIFORMITY IN CO-ROTATING TWIN SCREW EXTRUDER - A GEOMETRICAL STUDY OF SHEAR RATES IN A FULLY FILLED ZONE
Babu Padmanabhan , Chetan Chincholi Jayanth, May 2010
Increase in screw speed results in increased localized shear rates in co-rotating twin-screw extruders due to higher radial and meta-radial shear. This results in shear non-uniformity which in-turn results in degradation of shear sensitive material. Shear rates induced by kneading elements with different geometries are studied in the axial (longitudinal), radial and meta-radial shear planes. Elements with fractional lobed geometry having unequal tip angles show greater shear uniformity minimizing excessive shear in small regions. A careful study of the geometries of kneading elements and their shear distribution is provided for practical use in compounding application.
TWIN SCREW EXTRUSION OF THERMOPLASTIC POTATO STARCH
D. Lawton, G. Wang, Q. Liu, M.R. Thompson, May 2010
Among starch species, potato tends to have a much narrower processing window in extrusion machinery for the preparation of thermoplastic starch compared to other common starch sources from corn or wheat. The present study demonstrates through a series of screw design refinements, a working approach to setting up a reasonable processing window of this starch type and discusses the issues involved. Finally the paper demonstrates through a series of trials with one of the optimal screw configuration, the influence of shear and formulation on final properties for the thermoplastic product.
IN-SITU ULTRASONIC COMPATIBILIZATION OF PEN/LCP BLENDS
T. Kuboki, Y.H. Lee, J.W.S. Lee, W. Zhu, C.B. Park, M. Sain, May 2010
In-situ compatibilization of immiscible blends of PEN and thermotropic LCP was achieved by the ultrasonically-aided extrusion process. Ultrasonically treated PEN underwent degradation. In PEN/LCP blends, LCP acted as a nucleating agent. Ultrasonically induced copolymer formation was detected by MALDI-TOF mass spectrometry in the blends. Ultrasonic treatment of 90/10 PEN/LCP blends improved interfacial adhesion in fibers spun at intermediate draw down ratios (DDR), improving their ductility. The lack of improvement in the mechanical properties of fibers spun at high DDR after ultrasonic treatment was attributed to the disturbance of interfacial copolymer by high elongational stresses.
EFFECTS OF CLAY ON MECHANICAL PROPERTIES OF INJECTION MOLDED HIGH-DENSITY POLYETHYLENE/CLAY NANOCOMPOSITE FOAMS
T. Kuboki , Y.H. Lee , J.W.S. Lee , W. Zhu , C.B. Park , M. Sain, May 2010
This paper investigates the effects of clay on the mechanical properties of injection molded high-density polyethylene (HDPE)/clay nanocomposite foams that contained a very small amount of clay in the range of 0.1 to 1 wt%. Nanocomposite compounds were prepared by a melt blending masterbatch process and injection molded by using an advanced structural foam molding machine inwhich N2 was used for foams as a physical blowing agent.The results suggest that the addition of clay increased the flexural strength and modulus of both solid and foam nanocomposites as its contents were increased. The results also indicate that the foam nanocomposites always exhibited lower flexural properties but higher notched Izod impact strength than solid nanocomposites at each given clay amount.
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