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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DYNAMIC PROPERTIES OF CROSSLINKED POLYOLEFIN FOAMS
The material of choice in the foam industry for many years was Ethylene-Vinyl Acetate copolymers (EVA). This dominance was based on its flexibility, adhesion performance, and foaming window. In the last ten years, ethylene- ?-olefin inter-polymers (or Polyolefin Elastomers (POE)) have been integrated in foam formulations as a means to increase processability and cost efficiency. In recent years, the discovery of INFUSE™ Olefin Block Copolymers (OBC’s) has increased the benefits of using ethylene-?-olefin inter-polymers in foam applications. This paper shows that the characteristics that make INFUSE™ OBC’s of interest in Crosslinked (XL) foam systems are increased softness, improved shrinkage, and compression set resistance at elevated temperatures. The paper also shows that OBC foams long term fatigue behavior departs from that of EVA and POE foams with the same cure state. The room temperature data allowed one to draw the following conclusions: (i) OBC foams showed a more elastic response than EVA and POE as demonstrated by lower final strain and faster recovery after dynamic testing; the elastic response of OBC foams was attributed to its block architecture, and (ii) short chain branching based materials (OBC and POE) seemed to recover faster than the long chain branching based EVA foam.
GLASS FILLED POLYBUTYLENE TEREPHTHALATE WITH ENHANCED SURFACE AESTHETICS
Typically glass filled semi-crystalline polymers like polybutylene terephthalate (PBT) have poor surface aesthetics especially in gas assist molded high gloss surfaces like oven door handles but are still preferred due to their mechanical properties. Such surface issues have a tendency to show up more in dark colors like black which is one of the preferred colors for oven door handles. SABIC-IP has developed a new glass filled PBT based product to provide with improved surface appearance on gas assist molded in black colors. Higher gloss readings and lower glass fiber counts were observed on the surface of molded products.
SURFACE ENERGY EFFECTS OF PC/SAN/MWCNT BLENDS WITH THE ADDITION OF A REACTIVE COMPONENT
Carbon nanotubes (CNTs) have been shown to be a versatile filler that influences several properties favorably. One such property of concern is the electrical conductivity of multiwalled CNTs (MWCNTs) which can be transferred into insulating matrices by filler percolation. In melt-mixed co-continuous poly(styrene-co-acrylonitrile) (SAN)/ polycarbonate (PC) blends containing different types of MWCNTs, a selective localization of the CNTs in the PC phase is found. This was independent of the polymer phase in which the CNTs were first incorporated. This localization will be explained using the wetting concept. In the presentation we will show the effect of adding a reactive component.
INFLUENCE OF COMPONENT WARPAGE ONTO PROCESS CONTROL AND COMPONENT PROPERTIES DURING VIBRATION WELDING
Vibration welding is a well-understood and established joining technology in the industry. In numerous studies the process understanding and process control strategies have been developed. To reach reproducible weld properties, the phase of steady-state melt formation and constant melt-down rate must be achieved during the process. More recent results demonstrate the enormous influence of the decay time onto morphology and mechanical properties of the weld seam. These results confirm the known structure-properties relationship. Industrially manufactured components always have more or less deviations from the target geometry. Typical effects as large-scale warpage, local sink marks or lateral offset of the parts results in locally different conditions during the joining process. The current strategy in case of component warpage is to increase the joining pressure to achieve complete matching between the two joint surfaces. The force-depending deformation of the joint parts during welding results in locally different joining pressures over the weld length. These different joining pressures lead to locally different weld properties. The presented project shows the effects on process behavior and the results on weld quality, local and global. Longer welding times do not help.
IN-MOLD SURFACE MODIFICATION AND IN-MOLD PRINTING DURING INJECTION MOLDING
Surfaces of plastic parts often need a pre-treatment before they can be further bonded or painted. In the presented project an innovative method of process-integrated surface modification by surface-reactive injection molding has been investigated. Before the injection cycle starts a thin modifier film is applied uniformliy (or selectively) on the mold surface. Then the high temperature of the injected polymer melt is used to initiate a chemical reaction binding functional groups to the newly created surface of the plastic part. Controlling the adhesion processes like chemical reactions in the millisecond range is especially challenging. This means that no subsequent surface pre-treatment is needed in order to save costs, time and energy. In contrast to many of the commonly used methods, the modification effect is permanent. The surfaces can be functionalized in a broad range by tailoring the type of the modifier for e.g. hydrophobic or hydrophilic surfaces. In current investigations even the modification of polyolefins could be achieved successfully. One of the most promising applications would be In-Mold Printing where fully finished surface decorated parts can be produced during injection molding. Here even two subsequent processing steps are saved compared to the common printing process of polymer parts: the surface modification for better adhesion and the printing itself are integrated in the process of injection molding. This could be realized by printing patterns of modified paint on the mold surface, e.g. by pad printing. During injection molding the paint is transferred completely to the surface of the polymeric part, which develops at this point. In-Mold Printing shortens the process chain, saves material, energy and time and opens new application fields, e.g. the integration of printed electronics to low-cost plastic products in mass-production.
EFFECTS OF COMPONENT VISCOSITIES AND DISPERSED PHASE VOLUME FRACTION ON RELAXATION BEHAVIOR FOR POLYMER BLENDS
The influences of the viscosities of the matrix and dispersed phase, and the volume fraction of the dispersed phase on the relaxation behavior reflected on the Cole-Cole plot and the imaginary part of complex viscosity curve are analyzed using the Maxwell and the Palierne models and experimental data. It is found that these three parameters have a great impact on the radii of the circular arcs of the Cole-Cole plot. Moreover, the total relaxation time of the deformed droplets increases with the increase of the viscosity and volume fraction of the dispersed phase, especially the increase of the viscosity of the matrix. In addition, it is important to found that the Cole-Cole plot is invalid to analyze the miscibility of the polymer blend when the droplets of the dispersed phase have not enough time to relax during dynamic frequency sweep test.
CHANNEL FLOW SIMULATION WITH DELAYED FOLGAR TUCKER FIBER ORIENTATION MODEL
A 2-D channel flow simulation is performed with delayed Folgar Tucker model for rigid short glass fiber orientation. The continuity and Navier-Stokes equations are discretized using Galerkin finite element method and the constitutive equation for fiber orientation is discretized using discontinuous Galerkin finite element method. Material parameters have been taken from a study conducted earlier in our group. The effect of fountain flow is included in the simulations by using a pseudoconcentration method and performing a full solution of balance equations.
IN SITU GENERATED BICONTINUOUS REINFORCEMENTS
The principle subject discussed in the current study is a method to form bicontinuous reinforcement within a polyether ether ketone (PEEK) polymer matrix by using metal stearates as fillers. X-ray scattering, differential scanning calorimeter, dynamic mechanical analysis (DMA) and melt rheology were used to investigate the dynamics of the material and the structure of the components. Metal stearates affect the packing of PEEK molecules and reduce the total crystallinity by slightly changing the crystal growth of PEEK with no change in unit cell of PEEK. Melt rheology and DMA results suggest that PEEK is a dominant phase in the composites and the metal stearates form a secondary continuous phase in the polymer resin. The reinforcing effect of the metal stearates at low temperatures is maintained up to their softening temperature around 100°C beyond which PEEK begins to dominate the mechanical behavior. Effective moduli of metal stearates in composites suggest that the secondary metal stearate phase forms bicontinuous morphology.
THE SYNERGISTIC EFFECT OF SIO2 ON THE FLAMMABILITY PROPERTIES OF INTUMESCENT FLAME RETARDED POLY(EHTENE-CO-OCTENE) ELASTOMER (POE)/ POLYPROPYLENE(PP) BLENDS
As a toughening agent, poly(ehtene-co-octene) elastomer (POE) could raise the notched impact strength of polypropylene(PP), especially in low temperatures. Ethylene-octene/ polypropylene blends were widely used in many domains. An Intumescent flame retardant and SiO2 were introduced into ethylene-octene/ polypropylene blends as flame retardant and its synergistic agent. The flame retardancy of the new system was estimated with the UL94 test, cone calorimeter test, of which contained heat release rate test and smoke release rate test, and Thermogravimetric property was also investigated. According to the results of flammability tests, the SiO2 showed synergistic effect apparently when its content reached 1%(weight percent of the whole system, the same below).
GLASS FIBER REINFORCED ENGINEERING PLASTICS SIZING AN ESSENTIAL COMPONENT FOR PERFORMANCE
Fiber glass reinforced engineering plastics are increasingly important construction materials in transportation, electrical and other field applications. With the use of fiber glass reinforcements, certain material properties such as stiffness, strength and temperature stability are significantly improved. Combined with the base plastics, attractive material properties are obtained making them suitable for very demanding applications. Traditional performance attributes such as mechanical and environmental properties, reductions in total part cost as well as lightweight benefits allow these materials to provide answers to more complex applications, while meeting lightweight, recyclability, food contact and other requirements. It is essential to use the right fiber glass product with the right sizing specific to the application. Sizing provides a powerful solution for many processes and performance attributes of short fiber compounds and allows the final product to meet a variety of additional requirements. In this paper, the latest developments in glass fiber reinforcement will be reviewed, focusing on some of the most important engineering plastics such as polyamide, polyester and others. It will be demonstrated how very small amounts of glass fiber sizing can be very effective in realizing performance attributes over a wide range of requirements. In addition, examples will show how glass fiber reinforcements can greatly enhance the performance of certain biopolymers.
DETECTING POLYMER LONG CHAIN BRANCHING STRUCTURES BY USING ANALYTICAL RHEOLOGY
Polymer rheology is a very sensitive indicator of polymer long chain branching, and therefore can be used as a tool to determine polymer structures. This paper is thus focused on the study of the relationship between polymer linear viscoelastic properties and polymer structures using both rheological experiments as well as theoretical modeling methods applied to both model polymers and commercial polymers. In this work, the “hierarchical model” was employed to predict their rheological behaviors as well as to identify the impurities in the materials using the “analytical rheology” concept. After validating the tube model theory successfully on the model polymer melts, we tried to access the validity of the modeling predictions for commercial polyolefins.
LOOK UPSTREAM TO AVOID ‘GIGO’ PITFALLS IN EXTRUSION
The American phrase ‘garbage in, garbage out’ (GIGO for short) succinctly describes a problem often faced by plastics extrusion processors worldwide: No matter how well an extruder extrudes, its output will not be on-spec if the input blend is off-spec. When formulation problems do arise, the on-line proportioning system draws initial troubleshooting focus. But the problem itself (or its underlying cause) may lie elsewhere, farther upstream. This presentation systematically addresses the major process operations prior to extrusion (and beyond to include the materials themselves) in an effort to indentify and avoid the various pitfalls that may plague reliably accurate formulation.
EFFECT OF BLEND COMPOSITION OF EPOXIDIZED NATURAL RUBBER AND FLUOROPLASTIC VIA DYNAMIC VULCANIZATION
This study is purposed to develop a thermoplastic elastomer via dynamic vulcanization made of epoxidized natural rubber (ENR) and poly(vinylidene fluoride) (PVDF). Rubber parts were mixed at room temperature by using two roll mill, then fed in twin screw extruder with thermoplastic parts to occur dynamic vulcanization for pre-cured stage and compression molding for post-cured stage. This research was emphasized on the contents of ENR, PVDF and curing agent including the addition of PLA that affected on the properties of the dynamically vulcanized blends in comparison to the ternary ones. Mechanical properties including tensile strength and hardness were observed. Oil swelling test was studied by using 4 fuel oil types which are gasohol 91, gasohol 95, E20 and E85 at room temperature. It was found that increasing thermoplastic and DBPH contents have enhanced the tensile strength, young’s modulus and oil swelling resistance. Addition of PLA gave similar results as non-additional ones in term of oil swelling resistance.
COMPARATIVE STUDIES ON THE CRYSTALLIZATION BEHAVIOR OF POLY ETHER KETONE (PEK)
The paper describes the crystallization and melting behavior of poly (ether ketone), PEK , prepared by Gharda Chemicals Ltd, India and compared with PEK supplied by Victrex Plc, UK. The routes of synthesis of the two polymers are different. Gharda Chemicals synthesizes PEK using cheap chlorine based monomers whereas Victrex Plc, synthesizes PEK using expensive fluorine based monomers. Crystallization of PEK was studied under non-isothermal conditions with differential scanning calorimetry. Crystallization parameters were evaluated with standard equations and the results were interpreted on the basis of nucleation, crystallisation, and activation energy of crystallization. The behavior of Gharda PEK and Victrex PEK was found to be comparable.
RHEOLOGY AND MELT FRACTURE OF POLY(LACTIDES)
The wall slip and melt fracture behaviour of several commercial polylactides (PLAs) have been investigated. PLAs with molecular weights greater than a certain value were found to slip, with the slip velocity to increase with decrease of molecular weight. The onset of melt fracture for the high molecular weight PLAs was found to occur at around 0.2 to 0.3 MPa, depending on the geometrical characteristics of the dies. Addition of 0.5wt% of a poly(?- caprolactone) (PCL) into the PLA that exhibits melt fracture was found to be effective in eliminating and delaying the onset of melt fracture to higher shear rates.
OSHA’S COMBUSTIBLE DUST NATIONAL EMPHASIS PROGRAM AND COMBUSTIBILITY CHARACTERISTICS TESTING OF PVC RESINS AND PVC DUSTS
This paper provides an overview of the current and potential regulation of the hazards of combustible dust (CD) by the Occupational Safety and Health Administration (OSHA) and the influence of National Fire Protection Association (NFPA) standards and U.S. Chemical Safety Board (CSB) investigations on OSHA enforcement and rulemaking activities. This paper also presents the results of recent laboratory testing performed to determine the explosibility and other combustibility characteristics1 of samples of a variety of polyvinyl chloride (PVC) resin grades provided by resin producers. Explosibility testing was performed on samples of PVC dispersion resins, PVC copolymer resins, PVC suspension resins, and PVC dust particles sampled from a baghouse serving a PVC suspension resin production line. All test results fell into Class St 1, described as a weak explosion risk, when evaluated in a 20 liter test chamber. Because PVC resins by themselves do not have a known history of incidents where explosions occurred, this suggested the possibility that the test results from the 20 liter chamber test vessel reflected a false positive (or “overdriven”) situation caused by the ignition of the PVC particles as they passed through the flame of the ignition source rather than through the self-propagating deflagration that represents explosibility. As-received suspension resin samples from producers were retested for explosibility in a 1 cubic meter test chamber and the results indicated no explosion risk, falling into Class St 0. This suggests that, at least for the tested suspension resins, the test results from the 20 liter chamber test vessel reflected a false positive (or “overdriven”) situation and that the samples were not explosible. This paper was prepared for presentation at the SPE ANTEC on April 2, 2012.
TILTING DIE | THE CONVINCING NEW SOLUTION TO CENTRE AN ANNULAR DIE
A totally new solution was developed to centre the die in regard to the mandrel of an annular die. The tilting technology overcomes most of the drawbacks of the existing conventional centering solutions. The new tilting technology can be easily retrofitted to existing heads for pipes | for blown films and for the extrusion blow molding process. Tilting dies enable to further reduce remaining eccentric thickness differences in the extruded products. So they help to improve the quality of the products while in the same time the cost of the production is reduced.
High Performance EVOH Nanocomposites of Interest in Packaging Applications
EVOH are materials with broad application in high barrier packaging due to transparency and superior oxygen barrier. However | these materials suffer from strong plasticization in properties due to sorption of moisture | which handicaps their application under high moisture conditions such as those applied in many packaging cases. This paper shows the development of novel nanocomposites based on an optimized kaolinite grade | commercially marketed as O2Block® | which exhibit enhanced UV and gas barrier and decreased water permeability and sensitivity.
THE EFFECT OF COMPOSITION AND PROCESSING PARAMETERS ON THE MORPHOLOGY AND PROPERTIES OF PC/ABS/ORGANOCLAY NANOCOMPOSITES
In this study | blends based on poly(acrylonitrile-butadiene-styrene) (ABS) and polycarbonate (PC) were prepared and studied | in an attempt to explore the performance of mixtures deriving from recycling of waste electrical and electronic equipment (WEEE). The modification of ABS and ABS/PC blends via the incorporation of reinforcing fillers | such as organic modified montmorillonite nanoparticles (OMMT) | was also explored and its effect on the structure and properties was evaluated.
Failure Analysis of cracking HDPE cartridges. Optimization of Molding process using Dr. Taguchi Method of D.O.E.
This paper’s goal is to explain how to achieve the optimum molding conditions that minimize the effect of stress cracking without removing the causes of degradation during service use. Analyzing failure of HDPE caulking cartridges: due to premature initiation of cracking and brittleness at the cartridge wall.
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