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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Modeling and Analysis of Spin Coating on Spherical Surfaces
A formulation for modeling the spinning coating process on spherical surfaces is presented in this paper. The model can be adopted to predict film thickness profile on spherical surfaces with large central angles. The simulation results showed that the uniformity of final film thickness is not ideal with uniform initial film thickness distribution. The film thickness evolution and uniformity of film thickness were studied using this model and compared with literature to determine potential advantages of the new model.
Potential for efficiency improvements at different injection molding machines
Topic of this paper are the results of some investigations discovering potentials for improvements of two different injection molding machines with respect to the efficiency. During this investigations, the influence of process conditions on the energy consumption of two different driven injection molding machines have been focused. Finally some recommendations will be done for an improvement of the efficiency of the machines.
Laser Direct Structuring LCP for Mobile Antenna Applications
The rapid growth and global demand for wireless communication and increasing need for more functionality in smart phones have created a need for advanced engineering resin to meet new antenna requirements for mobile devices. This paper discusses performance of new laser direct structuring LCP grades and developmental grades with improved mechanical, thermal properties and dielectric properties engineered to meet new challenges of increased functionality and reduction in antenna size.
An Expanded Residence Stress Distribution Study in a Twin-Screw Extruder: The Effect of Stress Bead Strength
The ability to measure Residence Stress Distribution (RSD) in real time provides a greater understanding of the extrusion process. A method has been developed to characterize stress history within a 28-mm co-rotating twin-screw extruder (CoTSE) through the use of stress beads that break at critical stresses. Three different strength stress beads were used to provide an expanded and robust methodology. A Design of Experiment (DOE) approach was used to present the bead breakup results.
Residence Stress Distribution Study Using a Robust Design of Experiment Approach
A real time method of measuring Residence Stress Distribution (RSD) within in an 18-mm fully intermeshing, co-rotating twin-screw extruder (CoTSE) has been developed using stress beads. A Design of Experiment (DOE) grid allowed the results of the percent breakup of beads to be evaluated statistically. Further experiments have now been run to expand the mixing regimes inspected. The augmented range of operating conditions tested enabled a more robust and rigorous analysis of bead breakup trends.
Modeling of Single Ply Thermoplastic Polyolefin Roofing
A finite element simulation is developed to model the stress distribution of heat seamed Single Ply thermoplastic polyolefin (TPO) composite under FM wind uplift test conditions. Separate models are developed for the TPO layers, reinforcement layer, and lap-joint geometry in order to obtain an integrated TPO composite model. TPO membrane material and attachment parameters are evaluated for wind uplift enhancement. Good correlation is observed between model prediction and real wind uplift test results.
Resin Design for High Stiffness and High ESCR Performance in Rotational Molding Applications
This paper presents new developments in the design of ethylene copolymers for rotational molding applications with higher stiffness and ESCR requirements. The performance of novel ethylene copolymers is discussed based on phenomena fundamental to the rotomolding process and on the relative impact of the choice of comonomer, manufacturing technologies and resin design strategy.
Relating Polymer Viscoelastic Properties to Thermoforming Process: A Short Review
This paper reviews the relation between polymer viscoelastic properties and the plug-assist thermoforming process. One of the important attributes of polymers is their macromolecular interaction. Molecular interaction provides enhanced networks of molecules that contribute to minimizing polymer deformation at high temperatures. As a result, sheet sagging will be reduced during thermoforming. Additionally, molecular interaction could enhance the melt strength of the polymer by reducing its molecular mobility.
Upgrading the Capacity of an Existing Extrusion System
Several low-cost techniques are readily available to upgrade the capacity of an existing extrusion system. These techniques include upgrading a screw to restore the flight clearance due to wear, changes to the motor drive train system, and the use of high-performance screws. The technique used will depend on the rate limitation and the current process.
Troubleshooting and Mitigating Gels in Polyolefin Film Products
The term “gel” is commonly used to refer to any small defect that distorts a film product. Eliminating gel defects from extruded polyolefin film products can be difficult, time consuming, and expensive due to the complexity of the problem and the high levels of off specification product produced. This paper discusses the identification of gel types, the common root causes for gels, and the technical solutions for mitigating gels in film products produced using single-screw extruders.
Comparison Study of Talc and Nanosilica as Nucleating Agents for Low-Expansion Foaming Applications
This paper compares the effectiveness of talc and nanosilica as nucleating agents for generating polypropylene foams with high cell density and low expansion. Experiments were conducted in two stages: 1) In-situ foaming observation in a batch system; 2) Extrusion foaming. Nanosilica was more effective than talc in inducing cell nucleation under static conditions. However, in extrusion, their effectiveness in enhancing cell nucleation was similar due to the presence of extensional and shear stresses.
Characterization of iPP-PDMS Elastomers
An isotactic polypropylene-polydimethylsiloxane (iPP-PDMS) elastomer was prepared by reactive extrusion with tert-butyl peroxide. Rheology and thermomechanical analyzer (TMA) experiments demonstrate typical elastomeric behavior. Two complimentary techniques TMA and differential scanning calorimetry (DSC) were combined to estimate the density of iPP in the crystalline phase and to calculate the volume change associated with melting and crystallization thermal transitions. Further, the analysis confirmed the presence of crystalline iPP and amorphous PDMS phases in the elastomer
Fiber length and orientation distribution measurement of a charge for D-LFT compression Molding
Initial fiber orientation distribution (FOD) and fiber length distribution (FLD) of a fiber glass reinforced polypropylene charge for a D-LFT compression molded part were measured using image processing techniques. The FOD was measured from ?-CT scans using two different image processing approaches. These results are intended to be used in compression molding simulations.
Supercritical CO2 Improving Compatibilization of PP/PS Blend in Continuous Extrusion
Supercritical carbon dioxide (scCO2) was used in extrusion for the improvement of polymer blend properties. The compounding took place in two-single screw extruder. The morphologies of prepared blends were compared. Carbon dioxide was added at 3, 5wt% based on polymer melt flow rates. The experimental results indicate that the viscosity of PP and PS blends were reduced obviously and a sharp decrease in the size of the dispersed phase was observed. The impact strength of press molded 80/20 polypropylene /polystyrene blends increase by the addition of CO2.
Considerations regarding the EN13900-5:2005 determination by filter pressure value test
With the increasing demands on masterbatches the DIN EN13900-5 standard has been used as a more stringent and objective indicator of dispersion quality in a polymer matrix. Introduced within the last 7 years this method is being widely adopted in the industry. This paper will examine the history and the key components needed to assess the dispersion of a colorant in a masterbatch as well as equipment considerations.
Reliable Damping Parameters for Simulating Flow of High Molecular Weight HDPE
Determination of damping parameters from uniaxial extensional flow data per K-BKZ/PSM model are evaluated for high molecular weight HDPE resins. It was found that the damping properties depend on strain rate. The strain dependence, however, cannot be represented reproducibly as the relaxation mode-dependent ?k per Luo-Tanner from SER data. More efficient description of the strain dependency remains to be further explored.
Laser Transmission Welding for Medical Devices
Laser transmission welding is a well established joining technique for molecular diagnostic devices such as lab on a chip. This paper provides an overview about the effects of the injection molding parameters and the joining process parameters on weld strength. Design of experiments was used to maximize the weld strength. Additional optical and microscopic tests are required to validate the process for medical devices.
Die Design Effect on Internal Die Drool Phenomenon
n this work, the effect of die exit design on the internal die drool phenomenon occuring during extrusion of HDPE has been experimentaly investigated. It has been revealed, that firstly, the effect of flared length and die exit angle on the internal die drool intensity during extrusion of HDPE has non- monotonic character and secondly, flared dies are more stabilizing in comparison with chamfered dies.
Influence of the Endgroup Nature on the Rheological Behavior of Branched Polycarbonate Resins
Branched polymer rheology represents a very active field of research with important challenges, both from the scientific and technological point of view. A study of the rheological properties of branched polycarbonate resins is presented. The effect of the endgroup nature on the polymer melt viscosity was investigated.
A New Rheometer Concept Extending the Capabilities of Rotational Rheometer
A new rheometer concept based on two air bearing supported motors is introduced. The combination of two motors into one rheometer system offers increased sensitivity and new testing capabilities not possible before. Three completely different testing modes such as combined motor transducer, separate motor transducer and counter rotation are available in one single rheometer system. The aim of the paper is to describe the new technologies involved and to outline applications.
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