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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Mechanical Properties of Polyoxymethylene Copolymer Injection Moldings
Polyoxymethylene (POM) copolymer using dioxysolane (DOL) with polyethyleneglycol (PEG) was fabricated by injection molding. The DOL and PEG contents were varied, and the effects of them on morphology and mechanical properties were discussed. Small particles were observed in the case of PEG 1-5wt%, and the number and diameter increased with increasing PEG content. The charpy impact strength increased with increasing PEG content. Such morphology with particles resulted in the improvement of the impact strength.
Morphology of PC/ABS Blend Systems Fabricated by Injection Moldings
Morphology of PC/ABS injection moldings was observed by TEM in parallel to flow direction and transverse. The thin films, which thickness was less than 100 m, of PC and ABS were observed near the surface with regardless of injection speed, while ABS was in fibrous shape at the center. The geometry of butadiene rubber domains creating salami occluding SAN was a focus. It is confirmed that they elongated in flow directions.
An Approach to Gradation Mesh Generation in Injection Molding Simulation
Based on advancing-front method and Delaunay triangulation concept, a new interior point generation scheme is proposed. The longest edge at the current advancing-front is always chosen to create a new triangle element by using Delaunay triangle’s property, so that a high-quality graded mesh is obtained and a smooth transition in element size is maintained. The high-quality mesh can make plastics injection molding computer simulation more precise.
Influence of Clay Orientation and Aspect Ratio on Morphology and Mechanical Properties of Nylon-6/Clay Nanocomposites
The influence of clay orientation and aspect ratio on morphology and mechanical properties of nylon-6/clay nanocomposites is investigated. Our findings suggest that clay orientation can affect the nucleation and orientation of crystalline lamellae of nylon 6 matrix. The presence of clay also hinders the relaxation of nylon matrix during annealing. Consequently, clay aspect ratio and orientation can greatly influence the overall morphology and mechanical properties of the nanocomposite.
Simulation of Flow Patterns of Melt during Melting Process of Single-Screw Extrusion with Vibration Force Field
The polymer melting mechanism in a novel extruder with extra axial vibration was studied. A self-amended non-isothermal Maxwell constitutive equation was used in simulating the special flow patterns of melt in the melt film between the driving wall and the solid/melt interface with various vibration force fields. The simulation results indicate that within a certain vibration strength range, the vibration force field can optimize the distribution of the shear rate in the flow field, thus accelerates the melting process.
Novel Dynamic Nucleation Theory for Microcellular Plastics
Polystyrene microcellular plastics blown with supercritical carbon dioxide were prepared by novel electromagnetic dynamic foaming simulator. Bubble nucleation processes in stable and dynamic shearing flow field were analyzed. The experiments showed that after imposing vibration, cell size decreased and cell density increased. The key issue with dynamic nucleation is that the shear energy generated by mechanical vibration improved bubble nucleation. Novel dynamic nucleation theory was put forward from the viewpoint of shear energy in this paper.
Flow Dynamics in Injection Molding with Microfeatures
Filling the microchannels is very important in designing micro-injection molding, microdevices, etc. In this paper, flow dynamics was studied in injection molding with microchannels. A transparent PMMA mold was designed and the flow dynamics was observed. The experiment was performed using poly (ethylene oxide) (PEO) and polyacryamide (PA) aqueous solutions. The transient dynamic flow and flow competition between the base plate and the microchannels were observed. The flow observation was used to explain previous filling length results in microchannels during micro-injection molding.
The Effects of Runner Diameter and Cavity Size on Packing a Part in Injection Molding
This paper presents the study which challenges some of the classic theory regarding runner sizes as related to packing. This study has found that, in some cases, packing control can be maintained with runner diameters which may be as small as, or even smaller than, the wall thickness of the parts being molded. This study further showed that in some cases, increasing cavity size allowed for improvements in packing control. Both of these findings are contrary to the classical wisdom used for today’s runner designs.
Performance of a Machine Augmented Composite
An advanced machine augmented composite was fabricated and tested. This composite is composed of rigid polyurethane machines with pre-buckled walls as a reinforcement and soft polyurethane as a matrix. Dynamic properties of the composite were measured in the frequency of 0.1 ~100 Hz range at room temperature by load-controlled cyclic testing. Measured tan ? values and loss modulus showed noticeably higher values than the matrix did at the frequency range of 0.1~ 40 Hz.
Part Weight Prediction Using Capacitive Transducer in Injection Molding
Quality of the injection molding product is getting increasingly important in the industry. One of the most important product quality measurements is the part weight. In this paper, a novel method is proposed for on-line weight prediction with the use of a capacitive transducer (CT) installed inside the injection mold. Experiments with different conditions show that the proposed method of using CT signals, through simple linear fitting, can indeed provide on-line predictions of the product weight, providing a practical means for process monitoring and online quality control.
The Criss-Cross Die
The typical center-fed manifold-die has a pressure at the center higher than at the edges that gives rise to an uneven flow distribution. This is eliminated by the crisscross die, which has two end-fed manifolds with half-flows in opposing directions. One half-flow has a pressure gradient equal and opposite to that of the other. The two opposed half flows and pressure gradients combine in a main delivery manifold to create a uniform pressure across the width of the die. The result is a die that produces extremely uniform widthwise flow for use in sheet manufacture and coatings.
Dielectric Properties of Graphite Nanocomposites
Polymer nanocomposites are an emerging class of multifunctional materials that have not been optimized for their functional potential. In this study the dielectric properties of graphite polymer nanocomposites were evaluated. The objective is to develop an alternative costeffective nanoscale carbon material with comparable properties like carbon nanotubes for composite applications.
Barrier Liner Material with Nanocomposite for Packaging Applications
Plastic containers for beer, juice or CSD require matching plastic closures. Recently we developed a multi-layer barrier liner with nanocomposite that inhibits ingress of O2 and egress of CO2, into and out of the container. A passive barrier layer of Nylon nanocomposite and one or two reactive layers with scavengers are included in multi-layer structures. The multi-layer liner material with nanocomposite and reactive layers perform better than other barrier materials at very high relative humidity.
Injection Molded Part Split Solved by Cae Simulation Software
CAE injection molding simulation software was performed for prediction fiber orientation of a laser printer part. The cylinder shaped part made from a short fiber reinforced material was split when the part sits inside a gear assembly. The simulation software was able to identify the problem and duplicate the split location in the part. Then, the part thickness was modified and the gate location was optimized for improving mold filling and fiber orientation. The simulation software was also able to predict not split in the improved part. Actually, the simulation result was proved by the final production part.
Characterization of Virgin/Recycled Nitrile Rubber Blends
Blends of Virgin and Recycled Nitrile Rubber within a blend ratio of 10-30 %wt recycled NBR were studied. Reference was made to mechanical and physical properties. Results obtained indicate that a maximum percentage of 20%wt recycled rubber can be added to a NBR formulation without diminishing considerably final properties, since higher percentages promote a premature vulcanization. Concerning chemical resistance, an excellent oil resistance and a very low resistance to polar solvents were obtained for all formulations.
Predictive Damage and Failure Modeling for Composites Made of Baypreg®-F
As composite structures become more commonplace, advanced finite element analysis routines are required to accurately predict their structural performance. To aid design engineers, a simple damage and failure model for multi-laminate, anisotropic composites is evaluated for the prediction of stiffness and strength behavior. Results from the model are compared to experimental data.
Factors Affecting Single Screw Extrusion Output Rate of Thermoplastic Vulcanizates (TPVs)
Factors affecting the output rate of TPVs in a single screw extruder are investigated. The factors examined in this study include extruder rpm, barrel temperature, TPV pellet temperature, and TPV material selection. Process optimization is demonstrated for maximum output rate in a safe operating condition. The fundamental extrusion mechanism of TPV is discussed in contrast to that of other polyolefin resins.
Modeling the Interaction of Glass Yarns with Molten Plastic in the Cable Extrusion Process
We present a cable extrusion study that involves flow around a deformable moving fiberglass strand inside a cable extrusion die. In addition to non-Newtonian rheology, the fluid-structure interaction (FSI) between the polymer melt and the moving strand is highly non-linear. Using computational fluid dynamics (CFD), we have gained insight of our extrusion process by studying the strand deflection, the strand speed and the strand tension. The numerical results showed value in guiding the extrusion process.
Immobilization of EGF onto Silica Nanoparticles
Epidermal growth factor (EGF), has been identified as an excellent candidate for targeting cancerous tissue. This biomarker attached to polymeric particles can be used for detection, drug delivery, and imaging applications. Silica nanoparticles incorporating this biomarker were synthesized. These particles were coated with a second layer of silica containing carboxylated silane to enable coupling to the biomarker. Immobilization onto EGF was performed via carbodiimide chemistry, and assayed for using fluorescein isothiocyanate (FITC) to confirm EGF immobilization.
The Effect of Crosslinking on the Mechanical Properties of PLA/PCL Blend
The improvement of brittle behavior of PLA resin was studied by blending it with PCL resin. Peroxide (DCP) was added in order to form co-cross linked structure at the interphase. These materials were blended, and they were fabricated into thin films. DCP content was varied accordingly (0, 0.1, 0.2, 0.3, 0.5, 1, 2phr). The value of ultimate strain peaked at 0.1 and 0.2 phr DCP contents, but it was low at higher DCP content. It was thought that the peak changes of FTIR denote the compatibility at the interphase.
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