bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Matching of Experimental Polymer Processing Flows to Viscoelastic Numerical Simulation
Authors: Agassant J. F. , Baaijens F. , Bastian H. , Bernnat A. , Bogaerds A. C. B. , Coupez T. , Debbaut B. , Gavrus A. L. , Goublomme A. , van Gurp M. , Koopmans R. J. , Laun H. M. , Lee K. , Nouatin O. H. , Mackley M. R. , Peters G. W. M. , Rekers G. , Verbeeten W. M. H. , Vergnes B. , Wagner M. H. , Wassner E. , Zoetelief W. F. 
Published: December 2013

Abstract
This paper describes work carried out in order to match experimental processing flows to numerical simulation. The work has brought together a consortium that has developed reliable experimental methods by which processing flows can be achieved in the laboratory and then ranked against numerical simulation.
A full rheological characterisation of a selected range of polymers was made and the results compared from different laboratories. The data was fitted to a number of rheological models. Multi-mode parameter fitting was universal for the linear viscoelastic response. Particular attention was paid to the non linear response of the material. Prototype industrial flow experiments were carried out for a number of geometries in different laboratories and the flow birefringence technique was used to map out the experimentally observed stress fields for different polymers in a range of complex flows that contained both extensional and shear flow components. Numerical simulation was carried out using a number of algorithms and a range of constitutive equations.
In order to make a quantitative comparison between experiment and simulation, an Advanced Rheological Tool (ART) module was developed that was able in some cases to quantify the level of fit between the numerically predicted and the experimentally observed stress patterns. In addition the ART module was able to optimise certain non-linear parameters in order to improve the quality of fit between experiment and simulation.
Flow Characteristics of Screws and Special Mixing Enhancers in a Co-rotating Twin Screw Extruder
Authors: Brouwer T. , Todd D. B. , Janssen L. P. B. M. 
Published: December 2013

Abstract
The flow behavior of a Newtonian fluid through special mixing enhancers in a modular intermeshing co-rotating twin screw extruder has been examined. The mixing enhancers are slotted screws and gear mixing elements. Particular attention has been directed to drag and pressure flow characteristics and residence time distribution in such devices. The data obtained are useful for guidance in the selection of appropriate mixing elements and validation of flow simulation models for twin screw extruders.
Pressure/Throughput Behavior of a Single-screw Plasticising Unit in Consideration of Wall Slippage
Authors: Potente H. , Ridder H. 
Published: December 2013

Abstract
The mathematical models so far available for describing the throughput behavior of plasticising extruders were developed with the assumption of a wall-adhering melt. There are, however, a series of plastic melts, and also elastomers, polymer suspensions, ceramic materials and food products that display wall slippage during processing. A mathematical model has been developed for this material behavior, which describes the flow behavior for the unidimensional, Newtonian, isothermal case.
Apart from the development of the analytical model, the flow behavior of wall-slipping polymer melts was also analysed with the aid of finite element calculations (FEM). A comparison of the results for the pressure/throughput behavior shows that the calculation results tally very well for the two methods. It is thus possible to develop a procedure which makes it possible to describe the phenomenon of wall-slippage for the non-Newtonian, multi-dimensional, non-isothermal case.
The Prediction of Sharkskin Instability Observed during Film Blowing
Authors: Rutgers R. P. G. , Clemeur N. , Husny J. 
Published: December 2013

Abstract
The characteristics of sharkskin surface instability for linear low density polyethylene are studied as a function of film blowing processing conditions. By means of scanning electron microscopy and surface profilometry, is it found that for the standard industrial die geometry studied, sharkskin only occurs on the inside of the film bubble.
Previous work suggests that this instability may be due to critical extensional stress levels at the exit of the die. Isothermal integral viscoelastic simulations of the annular extrusion process are reported, and confirm that the extensional stress at the die exit is large enough to cause local melt rupture. However, the extensional stress level at the outer die wall predicts melt rupture of the outside bubble surface also, which contradicts the experimental findings.
A significant temperature gradient is expected to exist across the die gap at the exit of the die, due to the external heating of the die and the low conductivity of the polymer melt. It is shown that a gradient of 20°C is required to cause sharkskin to only appear on the inner bubble surface.
Investigation of Design Parameters and Novel Design of Petaloid PET Bottles
Authors: Lyu M.-Y. , Kim Y. H. 
Published: December 2013

Abstract
Carbonated soft drink (CSD) Poly(ethylene terephthalate) (PET) bottle contains pressurized liquid and its bottom design is petaloid in shape for self-standing. The trouble in this bottle is bottom cracking. In this study the design parameters of the petaloid bottom of the PET bottle have been investigated. Cracking test has been performed for different shapes of petaloid bottles and for several sizes of bottles, too. Through the cracking test, it has been concluded that the design parameters that affect the crack generation are clearance, foot length and valley width in the petaloid bottom. Computer simulation has been performed to seek for the optimum values of the design parameters that can reduce maximum principal stress concentration. Consequently the novel design of the petaloid bottom has been completed.
Residence Time Distribution Curves of Screw Elements in Twin-Srew Extruder
Authors: Calumby R. B. R. , Canevarolo S. V. 
Published: December 2013

Abstract
The additiveness of equivalent residence times method of deconvolution/convolution was used to determine the RTD curves of individual screw elements in the melt region of a twin-screw extruder. Initially RTD curves were obtained injecting a tracer (TiO2) at two different ports in the extruder barrel, using several screw configurations and operation conditions. Both ports are downstream, after the melt seal, well inside the molten polymer screw section. Then using the deconvolution method the RTD curve referent to the portion between the two ports was calculated. Finally, using again the deconvolution method and the data from several screw configurations the RTD of each individual screw element was obtained. The independence of screw element positions was also evaluated, where specially designed screws (e. g. changing the position and type of screw elements) were tested, showing no significant effect in the RTD curves. Kneading elements of 45 degrees (KB45) showed an important contribution of conveying, while kneading elements of 90 degrees (KB90) practically do not show any conveying, being characterized mainly by a pressure flow. With RTD curves of individual elements is possible, using the convolution method, predict the RTD curve of any screw configuration. Experimental measurements using screw configurations specially designed were used to check this analytical method. Finally it was applied to data published in the literature, obtained using other deconvolution methods and the results compared and discussed.
Three-dimensional Numerical Modeling of Co-injection Molding
Authors: Ilinca F. , Hétu J.-F. 
Published: December 2013

Abstract
In this work, a three-dimensional finite element flow analysis code is used to solve sequential co-injection molding problems. Non-Newtonian, non-isothermal flow solutions are obtained by solving the momentum, mass and energy equations. Two additional transport equations are solved for tracking polymer/air and skin/core polymers interfaces. Solutions are shown for a center gated rectangular plate. The effect of varying the melt/mold temperature and the ratio between the skin and core materials is investigated. The solution obtained for the same skin and core materials is compared with those in which viscosities of core and skin materials are much different. Finally, the solution for the co-injection of a C-shaped plate is presented. The three-dimensional modeling of co-injection molding provides the complete shape of the core polymer as well as the skin polymer thickness at any location. This is a major improvement over the traditional mid-plane approach, which is unable to recover the material behavior in critical regions as near corners, obstacles, and changes in part thickness.
Biaxially Oriented PP Films Using the Double Bubble Process
Authors: Benkreira H. , Talford M. C. 
Published: December 2013

Abstract
Biaxially Oriented Polypropylene (BOPP) film has become an increasingly important commodity over the last 30 or so years, offering an alternative to more traditional cellulose films with much improved mechanical and optical properties. The process is similar to the traditional bubble process for manufacturing films from a polymer melt, and the main difference in modelling the two processes lies in the constitutive equation employed. As the manufacturing process involves large strain deformations, a convected Standard Linear Solid constitutive equation was used in conjunction with the Pearson and Petrie force balance equations and a suitable energy balance to arrive at a mathematical model of the double bubble process. The non-linear ordinary differential equations forming the model require simultaneous solution, carried out using numerical techniques. An experimental program was conducted to obtain large-scale biaxial tensile test data. This data was used to determine the necessary material properties required to allow the model to be applied to a particular commercial process. Material data not obtained thus far has been estimated using previously published data for similar materials. Operating data was obtained from a fully instrumented full-scale industrial bubble process to enable the model to be validated. Initial comparisons between the model results and process data suggest that the model developed is a good starting point for a process simulation but that more accurate material data is required.
Rheological Effect of Zinc Surfactant on the TESPT-Silica Mixture in NR and S-SBR Compounds
Authors: Kim K.-J. , VanderKooi J. 
Published: December 2013

Abstract
The effects of zinc surfactant (ZB) on the TESPT (bis(triethoxy-silylpropyl)tetrasulfide)-silica mixture in NR (isoprene rubber) and S-SBR (solution butadiene-co-styrene rubber) were investigated, and their processability, dynamic, mechanical, heat build-up, blowout properties, and silica dispersion characteristics were compared. In the NR composite, the addition of ZB increased the reversion resistance time, tensile modulus, and blowout time and lowered the viscosity, heat build up, and tanδ values. In the S-SBR composite, the addition of ZB increased the heat build up, and tanδ values and lowered the reversion resistance time, tensile modulus, blowout time, viscosity, and tanδ values of the compound.
Over all, in the NR compounds, addition of the ZB significantly increased the processability and mechanical property; however, in the S-SBR compounds, it increased the processability but it was not effective in improving mechanical property.
Flow Visualization of Filling Process during Micro-Injection Molding
Authors: Yang S. Y. , Nian S. C. , Sun I. C. 
Published: December 2013

Abstract
Micro-injection molding has been under development for the mass manufacture of micro parts. This paper presents fundamental research on the filling characteristics during micro-injection molding. Flow visualization was employed to observe the fast filling process. A lab-made impact type micro-injection machine was developed and used in this study. Filling of 4 × 4 × 0.2 mm3 and 2 × 2 × 1 mm3 cavities in quartz glass molds was recorded with a high-speed video camera. The effects of the processing conditions on the filling behaviors are systematically studied. The processing parameters include air pressure, mold temperature, and melt temperature. Based on the analysis of flow patterns, it was found that the melt fronts advanced quickly and filled the cavity in less than 0.1 seconds. The filling process can be divided into impact-filling and pressure-filling stages. Mold temperature and air pressure are found to be the dominant processing parameters.
Visualisation and Analysis of the Flow along the Kneading Block of a Twin-screw Extruder
Authors: Carneiro O. S. , Poulesquen A. , Covas J. A. , Vergnes B. 
Published: December 2013

Abstract
The flow of a silicone oil of high viscosity along a block of staggered kneading discs of a co-rotating twin screw extruder was investigated with the use of an acrylic transparent barrel. A digital video camera recorded the flow path of a red dye, dispersed in the silicone oil, along the screws and in the intermeshing zone. Different geometrical configurations were studied, namely various staggering angles (+30°, 90° and −30 °) and thicknesses (7.5, 15.0 and 22.5 mm) of kneading blocks. The effects of these geometrical parameters on the pressure generation and filling ratio were investigated. It was observed that, even for negative staggering, the filling ratio of the kneading block was lower than one. Based upon these experiments, analytical expressions describing the filling ratio as function of geometry (staggering angle, thickness and number of discs) and operating conditions (feed rate and screw speed) were derived.
Melt Spinning of Reactive Extruded and/or Blended Polymer Fibers by Means of an Online Coupled Twin Screw Extruder
Authors: Beyreuther R. , Tändler B. , Vogel R. , Hoffmann M. 
Published: December 2013

Abstract
After some general introductory remarks to the advantageous application of a twin screw extrusion to the melt spinning the lecture deals with investigations of elastomeric fibers consisting of ethylene-octene-copolymers which have been grafted by organosilanes and additionally blended with polybutylenter-ephthalates (PBT) and/or polyesterelastomers (PEE), all by means of a reactive twin screw extruder coupled with a side feeding single screw extruder in an online melt spinning process. It will be demonstrated that considerably improved mechanical properties of the elastomeric EO-fibers can be reached with this additional blend step. All spun fiber samples will be characterized regarding their structural and mechanical properties extensively.
This work is a decisive expansion of our results published during the last two years regarding to the twin screw extrusion melt spinning [1 to 4].
Influence of Non-Newtonian Behaviour on the Processing Characteristics of Wall-slipping Materials
Authors: Potente H. , Kurte M. , Ridder H. 
Published: December 2013

Abstract
So far it has been assumed that when describing the flow process in single-screw extruder, the melt will be wall-adhering. Using certain process conditions, however, some materials such as PVCs, high-molecular PEs, elastomers, polymer suspensions, ceramic materials and food products become wall-slipping [1 to 4].
During simulation of the flow process using the Finite Element Method (FEM), the boundary condition of “wall-adhering” was substituted for “wall-slipping”. The numeric results refer to one-dimensional, non-Newtonian, isothermal flow processes and have been evaluated accordingly.
Since the wall-slipping properties are dependent on critical shear stress, the influence of non-Newtonian behaviour on wall shear stress is illustrated by investigating the barrel and screw root surface. Conclusions with regard to wall-slipping properties may be drawn from the resulting upper and lower limits.
The effect of wall slippage on pressure/throughput behaviour is examined along with the various velocity profiles, resulting from different compression ratios, dimensionless critical shear stress, material-related constants and screw configuration.
Flow Behavior of Sandwich Injection Molding in Sequential and Simultaneous Injection
Authors: Watanabe D. , Ishiaku U. S. , Nagaoka T. , Tomari K. , Hamada H. 
Published: December 2013

Abstract
The flow behavior of skin and core materials in co-injection molding was investigated to understand the flow patterns that could lead to core breakthrough in sequential and simultaneous injection molding. A spiral-flow mold was used and the core material was loaded with a black master batch to facilitate the monitoring of the core material. PC/ABS blend was used as the skin material and ABS was the core material. It was revealed irrespective of simultaneous injection time, sandwich injection molding display the four flow regions identified earlier i. e. primary injection region, core advance region, core expansion region and core breakthrough region. The flow length of core expansion region lengthened with increasing simultaneous injection time of skin and core material while the overall injection time decreased. It was also observed that the core became thinner and wider with increasing simultaneous injection time.
Rotational Moulding and Powder Processing of Natural Fibre Reinforced Thermoplastics
Authors: Torres F. G. , Aguirre M. 
Published: December 2013

Abstract
The present paper describes the development of a new processing technology: rotational moulding of natural fibre reinforced thermoplastics. Different polymer-natural fibre and polymer-flour systems have been characterised. A rotomoulding grade of high density polyethylene has been used as the polymer matrix for the experiments. Fibres, including jute, sisal and cabuya, as well as wood, pecan and rice shell flour of different types have been used as reinforcements.
The rotomoulding process for those composite systems has been studied using an in-house built two-axis rotomoulding rig with variable speed. The final products have been characterised with special emphasis on estimating the level of dispersion of the fibres and their degree of orientation, as well as the consolidation, sintering and bubble formation processes during the different stages. Comparisons have been made with other powder processing routes, involving the sintering of fibre (or flour) reinforced polymer particles including compression moulding.
Morphological characterisation techniques have been adapted to determine the structure-property relationships in these materials at different processing stages. Important improvements in the compression strength of the natural fibre reinforced rotomoulded products compared to the unreinforced materials, accompanied of a good dispersion level of the reinforcing fibres have been reported.
Electret-thermal Analysis of Polymer Blends
Authors: Pinchuk L. S. , Goldade V. A. , Kravtsov A. G. , Zotov S. V. , Jurkowski B. , Kelar K. 
Published: December 2013

Abstract
Electret-thermal analysis (ETA) was used to study polymer blends and processes of their compatibilization. Potentialities of ETA method have been visualized by the analysis of thermally stimulated current (TSC) spectra of the polyamide-polyethylene blends with a maleic anhydride functionalized styrene-(ethylene-co-butylene)-styrene block copolymer as compatibilizers. Peaks on TSC spectra of blend composites are identified with the composition and distribution of the components in the blend. Based on the physical method of analysis it has been proved that the charge state and structure of the blends strongly depend upon compatibilizer content and the degree of the melt mixing. It was confirmed previous conclusion that in a studied case compounding does not result in the formation of any new chemical compounds. ETA in combination with traditional physical methods appeared to yield trustworthy estimates of components distribution in the blend, the degree of their chemical interaction and on this base to preliminary forecast mechanical properties of blends.
Influence of Low Molecular Weight Additives on Die Extrusion Rheometer Flow of Thermoplastic Melts
Authors: Ahn S. , White J. L. 
Published: December 2013

Abstract
An experimental study of slippage induced in various thermoplastics in rheometers by the presence of small amount of low molecular weight additives is described. Capillary and cone-plate experiments are reported. A series of polymers of varying polarity including polyethylene, polypropylene, polystyrene, poly (methyl methacrylate) and polyamide 12 are compared. Five eighteen-carbon amphiphilic ω-compounds are used as additives including octadecanoic acid, octadecanamide, octadecanol, calcium stearate and zinc stearate. The greatest effects were found in polyethylene and polypropylene. Little or no effects are found with the other polymers. The most effective additives were octadecanoic acid and zinc stearate. Octadecanamide and octadecanol had some effectiveness. Mechanisms for this behavior are described.
Design of a Static Temperature Scanning Ultrasonic Measurement System and Application to Multi-phase Polymer Systems
Authors: Adebayo G. , Cakmak M. 
Published: December 2013

Abstract
A static bench ultrasonic setup was designed and implemented after due consideration for the heat transfer characteristics. The set up allows the measurement of the temperature profile of pertinent ultrasonic variables. The ultrasonic attenuation-temperature profiles in a few compositions of a partially miscible blend of Poly(α-methyl styrene acrylonitrile)/Poly(methyl methacrylate), as well as a PVC compound filled with mineral calcium carbonate fillers of three different particle sizes were followed using this set up. It was found that as the temperature was increased, the attenuation decreases with increase in the PαMSAN content of the blend, reached a peak and then decreases with further temperature increase. The peak value occurred in the 1-phase region while the peak temperature increases with PαMSAN content in the chosen blends. In the filled PVC system, the attenuation also increases with filler loading, especially within the vicinity of typical processing temperatures. The ultrasound technique, if applied to polymer processing, looks promising especially in closed regions along processing equipments.