bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dry Spinning of Polymer Fibers in Ternary Systems
Authors: Gou Z. , McHugh A. J. 
Published: December 2013

Abstract
This paper addresses the development and application of a two-dimensional, three component model for the dry spinning process of polymer fibers. The model presented is an expansion of a previously developed two-component dry spinning model [1] that incorporated both viscous and viscoelastic effects in the constitutive equation for the spin fluid, along with two-dimensional effects to account for radial variations in the fiber temperature and composition profiles along the spin line. The model presented in this paper includes the effects of water in the spin dope through incorporation of the diffusion equations for ternary mass transfer. Mass and energy balances on the gas side are also taken into account so that the effects of ambient conditions can be investigated. Calculations are based on the system: cellulose acetate-acetone-water. Results are presented for profiles of solvent concentration, temperature, and glass transition temperature profiles for typical industrial operating conditions. Force and stress distributions in the fiber at various points along the spinline, analyzed in terms of contributions from the viscoelastic and viscous terms in the constitutive equation, illustrate the role of these stresses in the freezing in of structure along the spinline. Model predictions are shown to be in good agreement with the principal characteristics of dry spinning.
Side Chain Extension of Maleated Polypropylene with Diamine
Authors: Kim K. Y. , Kim S. C. 
Published: December 2013

Abstract
In this study melt reaction of maleated polypropylene (PP-g-MA) with hexamethylene diamine (HMDA) and poly(propylene glycol)-bis-(2-propylamine) (Jeffamine D-400) was carried out. Three kinds of PP-g-MA (Polybond 3002, Polybond 3150 and Polybond 3200) having different maleic anhydride content of 0.2, 0.5, 1.0 wt.% respectively were used. FTIR spectra show that branches and crosslinks were formed through the formation of amide and imide linkages between maleic anhydride group and diamine, and titration results show that the reactivity of HMDA to maleic anhydride group is higher than that of Jeffamine D-400. For Polybond 3002, increases in melt index and decreases in molecular weight was found after reaction as a result of chain degradation. Hence increases in viscosity and moduli were not found in reacted Polybond 3002. Polybond 3150 and Polybond 3200 with higher MA content shows increase in molecular weight after reaction, and gels were detected when high concentration of HMDA was reacted. Increases in shear viscosities and modulus were observed in Polybond 3150 and Polybond 3200. In elongational viscosity measurement, when higher concentration of HMDA used, strain hardening was observed in Polybond 3150 and Polybond 3200.
Mold for Manipulation Microstructure Development
Authors: Silva C. A. , Viana J. C. , Dias G. R. , Cunha A. M. 
Published: December 2013

Abstract
The control of microstructure development in injection molding had attracted several important studies in the recent years, being well established that the thermo-mechanical environment imposed to the polymer melt depends on the material properties, molding geometry and processing conditions.
An entirely new design of an injection mold RCEM (Rotation, Compression and Expansion Mold) was developed and implemented, allowing for a wide variation of the filling and packing conditions in a flat disk geometry. One of the cavity walls (the ejection side) can rotate or move with a linear movement during the injection and holding stages. This enables several filling sequences and the variation of the cavity thickness. Two electric servomotors are use to directly drive those movements. Two temperatures and pressure sensors allow for the on-line process monitoring.
Several examples of the potential uses of the RCEM are shown for the cases of amorphous and semicrystalline polymers. Results obtained with short-fiber reinforced polypropylene are also presented.
Structure Development in Injection Molding: A 3D Simulation with a Differential Formulation of the Kinetic Equations
Authors: Smirnova J. , Silva L. , Monasse B. , Chenot J.-L. , Haudin J.-M. 
Published: December 2013

Abstract
The purpose of the present work is to introduce a crystallization law into Rem3D, a 3D code written in C++ and dedicated to the injection molding of polymers. We kept the basic hypotheses of Avrami's model and cast the kinetic equations into a differential system that is solved numerically. The variation of the density of potential nuclei with temperature is taken into account. Furthermore, the distribution of mean spherulite sizes can be deduced from the calculations. The second part of the paper is an experimental study of crystallization in well-controlled conditions (2D, isothermal or constant cooling-rate). It establishes a procedure for the determination of the nucleation and growth parameters used in the theoretical model, and gives a first validation of this model. Finally, the crystallization equations are introduced into Rem3D, in order to assess the feasibility of our new approach. Some typical results concerning the evolution of the transformed volume fraction in injection-molded parts are presented.
3D Simulation of Gas Assisted Injection Molding Analysis of Primary and Secondary Gas Penetration and Comparison with Experimental Results
Authors: Polynkin A. , Pittman J. F. T. , Sienz J. 
Published: December 2013

Abstract
Techniques for the three dimensional simulation of gas assisted injection molding (GAIM) are presented, including analysis of primary and secondary gas penetration and the use of time and position dependent heat transfer boundary conditions, computed in a segregated 3D analysis of conduction in the tool, through many cycles of moulding. Predictions are compared with results of experimental trials using a mould tool with a glass window that allows video recording of the process. Accurate agreement is obtained for gas penetration distances in primary and secondary penetration and for the forms of the gas channel cross sections, in a part that incorporates typical features of a GAIM application. The success of the simulations relies on careful detailing of the computational model and numerical procedures, including the use of dynamically updated flow and heat transfer boundary conditions, the use of sufficiently high resolution meshes, and efficient, high accuracy iterative solution techniques.
Effect of Material Species on Flash Generation of PPS/GF Composites
Authors: Higuchi H. , Goto H. , Koyama K. 
Published: December 2013

Abstract
Reduction of flash in injection molding is of great concern for manufacturers of electrical parts. In a previous report we have proposed a theoretical model for flash generation. The present study prepares five different poly(phenylene sulfide)/glass fiber composites using three different PPS; linear, branched and crosslinked PPS and measures the length of flash generated in the molding of the composites. Then, we have compared the flash data with a flash parameter defined in the model. This comparison has elucidated that flash length can be related with the flash parameter irrespective of PPS structure, as long as GF content is the same and the clearance of a gas vent is almost identical.
External Calibration in PA12 Tube Extrusion
Authors: Carin A. , Haudin J.-M. , Vincent M. , Monasse B. , Bellet G. , Amouroux N. 
Published: December 2013

Abstract
Elongation at break is one of the major end-use properties of polyamide 12 extruded tubes. It is strongly affected by the tube microstructure and the molecular orientation resulting from extrusion conditions. Molecular orientation was characterized by X-ray diffraction and birefringence evaluation in light microscopy. Measurements were carried out on (r, z) sections obtained by polishing and microtoming. On the other hand, polymer drawing was measured on line by tracer techniques. Calibration stage was determined as the key step of the process that generates orientation in tubes: as the tube is drawn through a cylindrical calibrator under vacuum and cooled from its outside surface, calibration leads to a highly oriented zone in the twenty external microns. Calibration conditions and elongation at break have been connected through orientation level in this region. Molecular orientation was found to strongly depend on the draw ratio in the calibration tank. Finally, birefringence of the tube external layers and elongation at break were successfully correlated. Elongation at break can be enhanced by reducing orientation resulting from calibration conditions.
Experimental Studies and Modeling of Development of Dispersion and Fiber Damage in Continuous Compounding
Authors: Shon K. , Liu D. , White J. L. 
Published: December 2013

Abstract
An experimental study of mixing of various particulates into synthetic elastomers and polypropylene is presented. For the elastomers, a batch internal mixer and a commercial continuous mixer were used to disperse various small particles including silica, carbon black, and CaCO3. For the polypropylene, this same continuous mixer plus a Buss Kneader, co-rotating twin screw extruder and an intermeshing counter-rotating twin screw extruder with different modular screw configurations were used to follow the dispersion of CaCO3. The breakage of glass fibers in these machines was also followed. Generally the most severe breakage of agglomerates and glass fiber was by modular intermeshing counter-rotating screws with special Leistritz elements. A model was developed for breakdown of agglomerates and fibers. The agreement with experiment was promising.
Reactive Processing of Thermoplastic Polymers: A Review of the Fundamental Aspects
Authors: Cassagnau P. , Bounor-Legaré V. , Fenouillot F. 
Published: December 2013

AbstractThe review is devoted to the fundamental aspects of the reactive processing of thermoplastic polymers. First of all, some reactive processing examples, including polymer grafting (vinyl silane, maleic anhydride) and/or functionalization, bulk polymerization (urethane, lactams, acrylate, ∊-capolactone), polyester modification and new copolymers synthesis, are presented. From a fundamental point of view, the review covers the state of the art in the domains of rheology (specifically modelling of rheo-kinetics), diffusion and mixing in highly viscous reactive or non reactive media. Finally, 1, 2 and 3-D simulation of the reactive extrusion process in twin-screw extruder is reported at the end of the review.
The Modelling of Mold Filling in Resin Transfer Molding
Authors: Gauvin R. , Chibani M. 
Published: December 2013

Abstract
The resin transfer moulding process (RTM) allows the industrial production of large FRP parts. In this technique layers of reinforcements (mats, woven rovings) are inserted into the mold cavity and resin is injected to fill the closed mold applying external pressure. Due to the strong interdependence between mold design, filling behavior and part quality it is most important to control the cavity pressure as the major influencing process parameter. A simple model is proposed to represent the pressure distribution during mold filling. It is based on Darcy's law for flow of liquids through a porous media and can be applied to single type or combinations of different reinforcements.
Rheological Characterization of Sulfuric Acid Solutions of Poly(p-phenyleneterephthalamide)
Authors: Kim B. C. , Hwang S. S. , Kim K. U. 
Published: December 2013

Abstract
Several grades of poly(p-phenyleneterephthalamide) (PPD-T) with different molecular weights were prepared. The rheological properties of sulfuric acid solutions of PPD-T were measured. In the vicinity of the critical concentration tan δ and η′/G′ exhibited a minimum value, but G′/2G″ and η* showed a maximum value. High concentrations produce an anisotropic phase. Tendencies of yield behavior were observed for these solutions in the anisotropic phase. Above the saturated concentration the solution system showed gel-like properties, i.e., with increasing concentration abrupt reduction of G′/2G″ and abrupt increases of η*, η′/G′ and tan δ were observed. With increasing temperature the viscosity of isotropic and anisotropic phases was decreased but that of biphase was increased. The critical concentration was reduced with increasing molecular weight, but increased with increasing temperature. Use of reduced variables seemed to eliminate molecular weight dependency on the critical concentration curve. The shear viscosity appeared to be proportional to (Mw)6.7.
Fiber Spinning with Molecular Models
Authors: Chen Z. , Papanastosiou A. C. 
Published: December 2013

Abstract
The isothermal fiber spinning of ciscoelastic liquid is analyzed successfully by means of the Curtiss-Bird integral constitutive equation derived from molecular theory, Glaerkin/finite element method, and Newton iteration. The analysis accounts for shear and elongational prehistories, and specified draw ratio or drawing force. Solutions are obtained at high values of elasticity, draw ratio and drawing force. The predictions agree with the analytic solution for Newtonian liquid in the limit of zero relaxation time and with experimental data from the literature on spinning of polystyrene and polypropylene melts.
Thermal and Crystallization Behaviour of Polyphenylene Sulfide in Engineering Polymer Blends with HDPE
Authors: Nadkarni V. M. , Shingankuli V. L. , Jog J. P. 
Published: December 2013

Abstract
The thermal and crystallization behaviour of polyphenylene sulfide (PPS) in its blends with high density polyethylene (HDPE) is reported. Three grades of HDPE ranging in MFI from 0.4 to 52 were used in the investigation. The effect of composition and molecular weight of HDPE on the crystallization process and morphology of PPS in the blends has been investigated by the technique of Differential Scanning Calorimetry (DSC).
In the blends, PPS crystallizes in presence of molten HDPE. It is observed that the morphology of PPS in terms of crystallite size and crystallite size distribution in the blends is significantly affected by blending with HDPE. The temperature onset of melting was found to increase with increasing HDPE content and the melting peak width was found to decrease with increasing HDPE content. This indicates a larger crystallite size and a narrower crystallite size distribution of PPS in blends. The effect is more pronounced in HDPE-rich compositions. The extent of the variation in the temperature onset of melting and peak width were comparable for all the grades of HDPE. The degree of crystallinity of PPS in the blends is reduced significantly (55–70%) in HDPE-rich blends. Therefore, it is concluded that the crystallization of PPS is affected by the presence of HDPE melt.
The crystallization scans of PPS in the blends, obtained in the cooling mode, did not show any evidence of accelerated nucleation. On the other hand, a marginal reduction in the temperature onset of crystallization was observed. The temperature range of crystallization of PPS in the blends was found to be less for all compositions except for 90/10 (PPS/HDPE). In summary it is concluded that blending of HDPE with PPS influences the crystal growth of PPS significantly although the effect on its homogeneous nucleation is also considerable. As a result, the morphology of PPS crystallized in blends is different from that of the homopolymer. The changes in the morphology of PPS are not sensitive to the molecular weight of HDPE probably because of the high temperature of PPS crystallization relative to the melting point of HDPE.
The Processing Science of Thermoplastic Structural Composites
Authors: Cogswell F. N. 
Published: December 2013

Abstract
A sound scientific basis for understanding what happens during the processing of materials, and how that stage affects the service performance of the structure, is an essential prerequisite to the development of efficient low cost fabrication technology. This paper considers the phenomena - chemical, thermal, thermodynamic and rheological - which occur during processing and reviews the information which we have available today as a basis on which to build a more comprehensive study and data base.
Effect of High Molecular Mass Tail in the Mol Mass Distribution of Polypropylene on Injection Molding
Authors: Qian R. , Guo M. , Li S. 
Published: December 2013

Abstract
The effect of high molecular mass (MM) tail in the molecular mass distribution (MMD) of polypropylene (PP) on injection molding has been studied using injection molded tensile bars from a commercial PP resin and two samples of the above resin deprived of the high MM tail in different degrees by controlled degradation during extruder reaction with an added processing aid named Promax. The central portions of the tensile bars were studied by polarizing microscopy of microtomed sections parallel and perpendicular to the melt flow direction, and by density and birefringence profiles across the thickness of the bar. Mechanical properties and acoustic emission behavior in stretching of these injection molded tensile bars are also discussed. The experimental results show that by stripping off the high MM tail in the MMD the injection molded tensile bar has smaller degree of crystallization, less frozen orientation, improved uniformity across the thickness and the thickness of the skin part is greatly reduced. Better quality of the fabricated articles is to be expected by using Promax with PP for injection molding.
Process Analysis of a Laboratory Internal Mixer
Authors: Menges G. , Grajewski F. 
Published: December 2013

Abstract
In order to gain an idea of the flow processes in an internal mixer coloured mixtures were produced. Using these the randomness with which the distribution of the flow properties in the mixing chamber occurs could be shown. The thermal boundary conditions were found to have a strong effect on the flow processes in several regions of the chamber. Further experiments showed that the feeding behaviour of the mixture between the rotors and the time required for the incorporation both depend highly on the wall temperatures. In practice, fluctuating wall temperatures are caused by start-up effects, because mixing is a discontinuous process. A model was developed with which the variation of the internal wall temperatures can be calculated. This forms a basis for estimating the conditions to adjust heating systems in order to minimize temperature fluctuations.
Rheovulkameter
Authors: Moos K.-H. 
Published: December 2013

Abstract
In practical rubber processing the compounds will be subjected to high shear rates. Hence in order to optimize processing conditions and also to guarantee a constant quality of the compounds it's a must to test processibility of rubber compounds in the shear rate range of practical processing. Processibility of rubber compounds is predominantly determined by its viscosity that's balanced by two effects; viscosity of these materials decreases drastically with increasing shear rate (pseudoplasticity) but increases markedly with the onset and development of curing. The rheovulkameter has been developped especially to take care of these effects and allowing to measure easily and fast processibility of rubber compounds under conditions of practical processing. It can be used like a capillary rheometer but like an injection molding tester as well. Rheovulkameter tests given information about both: flowing (Rheo-) and curing (Vulkameter) of rubber compounds and other curing systems, too.
Modelling Flow in Pin-Barrel Screw Extruders
Authors: Brzoskowski R. , White J. L. , Szydlowski W. , Nakajima N. , Min K. 
Published: December 2013

Abstract
The flow in a pin-barrel extruder has been analyzed based on a Newtonian fluid model. A numerical simulation based on the FAN method of Tadmor and his coworkers and an analytical model were used. The calculations show that the introduction of slices into screw flights and pins make the apparatus a much poorer screw pump. It would appear that the machine is though an effective continuous (distributive) mixing device.
Polymer Melt Temperature in Single Screw Extrusion
Authors: Wilczynski K. 
Published: December 2013

Abstract
An attempt of estimation of the melt temperature fluctuation (in a single screw extrusion) by means of dimensionless numbers has been made. To this aim the screw metering zone has been considered by presentation of equations of motion and energy which describe the polymer flow within that zone in a dimensionless form (a model of a viscoelastic fluid has been assumed). It has been shown on the basis of the performed measurements that the best correlation with the temperature fluctuation may be obtained by means of Fourier number. Applicability of that number for the estimation of the temperature fluctuation has been discussed. A concept of criterion of estimation of the temperature fluctuation based on the Fourier number has been presented which would take into account an influence of polymer melting upon said fluctuation. Use of that criterion has led to a good agreement (correlation) with the experimental results.
DSC Studies on Fibre-Filled Polyethylene
Authors: Hatakeyama T. , Kitano T. , Klason C. 
Published: December 2013

Abstract
Four kinds of inorganic fibres: carbon, silica glass, brass and aluminium, were filled in two kinds of low density polyethylenes (PE, Melt Flow Rates (MFR) at 190°C, 2.16 kg; 4 and 8 g/10 min) by extrusion molding. The filling ratio of fibres was varied from 0 to about 20% in volume. The melting and crystallization of the above systems were measured by differential scanning calorimetry. The fibre-filled PE was crystallized at a temperature higher than that of the original PE. This phenomenon was observed through a wide range of cooling rate. The temperature of the main melting peak moved slightly to the low temperature side and a broad shoulder peak appeared, as the filling ratio of fibre increased. It was also recognized that the maximum temperature of the molten state affected the crystallization behavior of the system. This was observed for the fibre-filled PE having low melt flow rate. The variation of fibre species scarcely affected the melting and crystallization behavior. The results suggested that the filled fibre accelerated the nucleation process and retarded the crystal growth of PE.
Computer Simulation of Melt Viscoelasticity Functions for Binary Polyblends
Authors: Plochocki A. P. , Dey S. K. , Kiani A. 
Published: December 2013

Abstract
Composition dependence of the polyblends' properties is usually associated with a synergism (the positive deviation from additivity). Using the bicubic spline interpolation technique and the melt viscoelasticity data the effects of shear stress on the location and intensity of the synergism is demonstrated for a set of binary mixtures of commercial polyolefins. Principal patterns of the “transient” and the “set-in” synergisms are identified.
Rheological Properties of Glass Fiber Filled Nylon 6 Composite System
Authors: Park T. S. , Kim K. U. 
Published: December 2013

Abstract
The dynamic and physical properties of neat and glass fiber filled nylon 6 systems were examined. The dynamic viscosity of neat nylon 6 melt was well fitted to:

(I)

η
′

=
a
/

(

1
+
b

ω

)

c

For the glass fiber filled nylon 6 composite systems, however, a modification of Eq. (1) was required to accommodate the viscosity data. Various types of rheological models are examined to describe the effect of glass fiber on the suspension viscosity, and respective constants of models were determined by a curve fitting. A silane coupling agent had a profound influence on the rheological and physical properties. It increased the dynamic viscosity of composite and yield value, but slightly decreased the activation energy of flow, particularly at high frequency range. Further, it increased the loss factor over the frequency range examined. Plot of storage modulus against loss modulus instead of frequency eliminated the effects of temperature and coupling agent. From the tensile fractured surface of coupling agent treated system, a fibrillar structure was observed.