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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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.
Compatibilizer Additives for Improving the Delamination Resistance of PET/Pa-MXD6 Multilayer Coinjection Stretch Blow Molded Bottles
The delamination resistance of multilayer PET/ PA-MXD6 coinjection stretch blow molded bottles was found to be significantly improved through the use of small amounts of specific dual-functional compatibilizer additives, blended into the nylon layer during the sequential coinjection molding step. Such modified multilayer PET bottles resist delamination even under stress-concentrated impact testing conditions.
The Effect of Coathanger Die Manifold Symmetry on Layer Uniformity in Multilayer Coextrusion
Multilayer coextrusion is a process in which two or more polymers are extruded and joined together in a feedblock or die to form a single structure with multiple layers. This paper will discuss the effect of die manifold channel symmetry of the flow of coextruded structures through coathanger style dies.
Lightweight Fastening Solutions for Thermoplastic Material
The constant improvement of the suitability of the fastener for light weight design applications is a development focus at EJOT. The DELTA PT® ALU, made of high-strength aluminum, is the answer to the constantly increasing demands on the direct assembly of plastic. The basis for this special fasteners is the proven DELTA PT® screw with the innovative thread geometry. The DELTA PT® ALU can be an alternative for the commonly used steel screws in many applications. Weight saving potentials can be utilized and the easy fastening of the plastic parts is also maintained.
Common Installation Failure Modes for In-Service Plastic Piping Components and Systems
Plastic pipe components are generally constructed into high integrity, high durability systems. However, some poor installation practices occur with sufficient frequency that they have been noted by the authors as recurring in root cause failure analyses. These installation based root causes differ with the application environment and the material of construction. This paper will address poor installation practices for polyethylene, poly vinyl chloride and chlorinated poly vinyl chloride based piping systems.
Innovative Waterborne & UV Resins for Plastics & Automotive Interior Applications
Innovative Waterborne & UV Resins for Plastics & Automotive Interior Applications
Wetting Measurements for Rapid Qualification of Surface Preparation Processes
Surface treatments of metals and polymers are frequently necessary to control properties such as adhesion of paints and sealants. Because surface properties are determined by only the uppermost few molecular layers, measuring these properties in manufacturing environments can be challenging. Water contact angles can be obtained very rapidly and conveniently and provide sensitive, quantitative feedback of surface properties important for adhesion.
Ensure Safe Operation of the GRP Lining Between Overhaul Period
Application of the electrical resistant and diffusion laws is effective way of the estimation of the ensure safe operation of the GRPL between overhaul periods and increase reliability of the technological equipment of concrete, steel or high filler plastic.
Determination of Thermal Conductivity for Industrial Applications
The thermal conductivity of various thermally conductive thermoplastics commercially available was determined experimentally and is compared with da-tasheet values. It was found that in most cases the thermal conductivities in-plane and through-plane deviate substantially from the manufacturers' values. The rea-sons as different measurement methods, part geometry and specimen preparation are discussed in detail in this paper. Finally the use of standardized methods is recommended.
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