bluuebunny/crossref_metadata_2025_split huggingface dataset:
Easy Tear Multilayer Film of Biaxially Oriented PA6/MXD6 by Double Bubble Tubular Film Process
Authors: Takashige M. , Kanai T. 
Published: December 2013

Abstract
In the market, a film which is adapted to environmental and barrier problems and easy tear property is desired. A previous report discussed easy tear PA6 film. This report discusses the film having not only easy tear, but also high barrier properties.
A biaxially oriented PA6/MXD6 blend film produced by double bubble tubular film process does possess gas barrier. So a multilayer film having high gas barrier layer and keeping easy tear cut has been studied. High gas barrier layer of high content MXD 6 in the center layer is added to PA6/MXD6 blend film in the outer layers.
When MXD6 blending ratio of PA6/MXD6 blending film layer is 30 %, the property of easy straight line cut is obtained. It is found that the plate-like cylinder structure was formed in the observation of TEM for PA6/MXD6 blend film.
The multilayer biaxially oriented film composed of PA6/MXD6 blend layer and MXD6 high content layer keeps high strength, easy tear property and high gas barrier. Namely, the material and production technology of a PA6 film could solve environmental and barrier problems.
Rotational Moulding of PVC Plastisol
Authors: Marcilla A. , García J. C. , Ruiz R. , Sánchez S. , Vargas C. , Pita L. , Beltrán M. I. 
Published: December 2013

Abstract
The viscosity during the earlier stages of the gelation process of plastisols formulated with 15 different commercial plasticizers has been obtained. Plastisols prepared were rotomoulded and mouldings obtained were characterized according to their wall thickness distribution. This parameter strongly depends on the minimum viscosity and on the rate of viscosity change during gelation (slope of the curves during the viscosity increase), and also on the temperature where no more flow of the plastisol is observed (gelation temperature). These variables are conditioned by the characteristics of the plasticizer and PVC employed, among other variables.
The effect of plate and arm velocity and rotation rate on the wall thickness distribution was also studied.
A simple model has been proposed to correlate the initial stage of the gelation of PVC plastisols formulated with the phthalate plasticizers. The suggested model assumes that the plastisol is a suspension constituted by a continuous phase (initially pure plasticizer) and a discontinuous phase constituted by PVC particles. It has been considered that the viscosity of the plastisol is influenced by the average mass molecular weight of the continuous phase and the temperature. The quantity of PVC dissolved in the continuous phase has been calculated by using a generic n-order kinetic equation for PVC dissolution rate. Additionally, a swelling process of the PVC particle by the plasticizer has also been considered and its effect on the viscosity of the suspension has also been accounted for. The model proposed provides a very good fitting of the sharp viscosity increase observed and is useful to predict the evolution of the viscosity of the parts in a rotomoulding process.
A Dilatometer to Measure the Influence of Cooling Rate and Melt Shearing on Specific Volume
Authors: van der Beek M. H. E. , Peters G. W. M. , Meijer H. E. H. 
Published: December 2013

Abstract
We developed a dilatometer to investigate the specific volume of polymers as a function of pressure (to 100 MPa), temperature (to 260 oC), cooling rate (to 100 oC/s), and shear rate (to 80 1/s). The dilatometer is based on the principle of confined compression and comprises of a pressure cell used in combination with a tensile testing machine with rotation capability. The design of the pressure cell is a mixture of a traditional ‘pistondie type’ dilatometer and a Couette rheometer, i. e. piston and die make up an annular shaped sample spacing. Typical dimensions of annular samples are: inner radius ri = 10.5 mm, outer radius ro = 11.0 mm, height h = 2.5 mm, and a typical mass of about 60 to 70 mg. Silicon grease is used to reduce loss of hydrostatic pressure in the sample due to friction occurring between the solidifying sample and the dilatometer wall. Specific volume measurements at low cooling rate using an isotactic polypropylene (i-PP) are compared with measurements performed using a commercial bellows type dilatometer, showing relative differences in the range of 0.1 to 0.4%. Finally, results for an isotactic polypropylene are presented showing a profound influence of cooling rate and melt shearing on the evolution of specific volume.
Nozzle Injection of Physical Blowing Agents in the Injection Molding of Microcellular Foams
Authors: Bravo V. L. , Hrymak A. N. 
Published: December 2013

Abstract
Results obtained from the implementation of a physical foaming system for injection molding are presented. The implemented design involves the injection of gas in the upstream side of a special nozzle composed by a static mixing element (SMX type) and a shut-off valve. In order to avoid the formation of large pockets of gas in the injection point, a porous metal plug is used to create a multiple point injection area with 20 lm size pores. Gas injection simultaneously with polymer melt injection gave a consistent foamed material. However, given the total pressure drop in the system of static mixers, runners and mold, there is an inherent operational pressure limitation. The polymer injection pressure needs to be kept at a pressure below the gas injection pressure, therefore limiting the speed at which the polymer can be injected in the mold.
Experimental Study on the Filling of a Micro Injection Molding with Cylindrical Dot Patterns
Authors: Chang H.-C. , Young W.-B. 
Published: December 2013

Abstract
This study is to investigate the fabrication of a mold insert with negative cylindrical dot micro features using the LIGA-Like process and molding of the component. The effects of molding conditions on the filling of the polymer melt into the negative features were experimentally studied. A parametric study of the effect of the molding conditions on the filling of microstructure in micro molding was conducted. Increase of the mold temperature or injection rate is an effective method to ensure the complete filling of the microstructure. The application of packing pressure was shown to improve the filling in the microstructure also. With the low aspect ratio used in this study (about 0.2), the microdot array can be completely filled with the right selections of injection rate and mold temperature without vacuum.
Two Dimensional Description of Pressure-Throughput Behaviour of Newtonian Materials Considering Wall Slippage Effects
Authors: Potente H. , Kurte–Jardin M. , Klus S. , Timmermann K. 
Published: December 2013

Abstract
The description of pressure-throughput behaviour of wall adhering melts in plastifying machines has been issued in a number of publications, e. g. [1 to 4] in details. Nevertheless there are a variety of polymer melts as well as elastomers, polymer suspensions, ceramic materials and food stuff, which do not behave wall adhering in the course of manufacturing. The theoretical discussion of the pressure-throughput behaviour has not sufficiently been described up to now. Worth's [5] case studies include the isothermal one-dimensional flow of a Newtonian medium in an unwinded screw channel. He assumed that after exceeding a critical shear rate the slipping process starts on the barrel wall only – but not on channel wall and screw root surface. Mennig, [6 to 9] took up this statement again and assuming a shear rate on the barrel wall as well as on the screw root surface he derived simple relations for the radial velocity profile from it. Lawal and Kalyon [10 to 12] have developed an analytical model that describes the behaviour of visco-plastic liquids in flat channels for different quotients of wall slippage, which are derived from the wall slippage quotients on screw root surface and on barrel wall.
A mathematical model describing the flow behaviour for the two-dimensional Newtonian, isothermal case has been developed for wall slipping materials in order to describe the pressure-throughput behaviour multi-dimensionally.
In addition to the development of the analytical calculating model the flow behaviour of wall slipping polymer melts has been analysed by using the finite-element-calculation (FEM). Comparison of the pressure-throughput behaviour results show a high degree of conformity in the calculation results.
State of the Art: Recycling of EPDM Rubber Vulcanizates
Authors: Sutanto P. , Picchioni F. , Janssen L. P. B. M. , Dijkhuis K. A. J. , Dierkes W. K. , Noordermeer J. W. M. 
Published: December 2013

Abstract
Since the past few decades, environmental issues have become a serious concern in society. It is a requisite for the industry to minimize waste, in order to protect the environment from being polluted. The term waste here comprises processing waste and post-consumer waste. The amount of processing waste should not be underestimated since it might consist of approximately 10% of the total production. The recycling of EPDM rubber is an interesting topic, especially if considered in connection with the continuous market growth of EPDM. This paper is a summary of efforts that have been taken so far on this subject. Studies done on EPDM recycling include reusing EPDM as filler in new rubber products and chemical, thermal, and mechanical devulcanization of EPDM in order to achieve a material that resembles the virgin one and could be revulcanized. Such studies on EPDM recycling are discussed extensively and in the conceptual frame of more general rubber recycling processes.
Thermal Flow Instability in Metal Injection Molding: Experiment and Simulation
Authors: Stevenson J. F. , Ilinca F. 
Published: December 2013

Abstract
Metal injection molding (MIM) is similar to plastic molding in many respects, but MIM compounds (metal powders with polymer binders) are more susceptible to thermally induced flow instability because of their higher thermal diffusivity. The flow patterns for a 17-4PH MIM compound were observed and simulated for mold filling through a diaphragm gate over a range of filling times and melt-mold interface temperatures. Simulation predicted the observed free annular jet and internal voids in the molded part and also predicted that initial contact with the outside wall of the gate would eliminate the jet, thereby reducing voids and surface defects. Parts made using a mold with a thicker gate verified these predictions. For combinations of operating conditions and mold geometry that gave large thermally induced viscosity gradients, both observation and simulation showed unstable, asymmetric flow. In these cases, flow slowed and stopped in one region of the gate and accelerated in other regions. When the flow was inherently unstable, simulations predicted an exponential growth in maximum temperature differences at symmetric locations in the mold gate. Based on 34 experimental observations and 102 simulations, a boundary was established between regions of stable and unstable flow in terms of the dimensionless Graetz number Gz (ratio of heat conduction time to fill time) and B, a dimensionless ratio indicating the sensitivity of viscosity to temperature differences in the mold. To establish a common basis for comparison of simulation and experiment, the melt-mold interface temperature was estimated using a heat transfer coefficient, which was a fixed value for experiment and a parameter for simulation.
Pressure and Temperature Dependence of LDPE Viscosity and Free Volume: The Effect of Molecular Structure
Authors: Sedlacek T. , Lengalova A. , Zatloukal M. , Cermak R. , Saha P. 
Published: December 2013

Abstract
Temperature and pressure dependencies of shear and elongational viscosities were examined using rotational and capillary rheometers. Two different batches of the same polymer grade have shown that the molecular structure diversion significantly influences the magnitudes of pressure coefficients, which vary more than the temperature coefficients. The pressure effect on viscosity notably depends on the amount of long-chain branching in polymer. Further, the paper shows that pVT data analysis via the Simha-Somcynsky equation of state can be employed to reveal differences in temperature and pressure viscosity dependencies through the free volume fraction.
Functionalization of PP with Sulfonyl Azide through Reactive Processing
Authors: Li Q. , Tzoganakis C. 
Published: December 2013

AbstractThe functionalization of polypropylene (PP) by 4-carboxybenzene sulfonyl azide (CBSA) was investigated in a batch mixer and the reaction was monitored through FTIR,1H-NMR and XPS spectroscopy. The degree of grafting was found to increase initially with azide feed content and subsequently to level off at azide concentrations of 2 wt.%. Experiments performed at different reaction temperatures showed that a maximum degree of grafting was obtained around 190°C. The linear viscoelastic properties the functionalized PPs were also evaluated by oscillatory shear measurements and were found to correlate with the grafting degree results. Finally, the adhesive properties of the functionalized PPs were evaluated through peel tests on aluminum substrates. The peel strength increased with the degree of grafting and it was found to be significantly higher for purified samples than for non-purified ones. Finally, it was demonstrated that the cooling rate of the PP/aluminum laminate specimens had a major effect on the peel strength.
Development of Planar Orientation in Polymer Processing
Authors: Horio Masao 
Published: December 2013

Abstract
A critical discussion is presented of the development of planar orientations in various polymer processing operations. These include tubular blown film and subsequently drawn and multiply stretched blown films. The response of polyethylene, various nylons, poly(ethylene terephthalate), cellulose and poly(p-phenylene terephthalamide) are discussed.
A Dispersive Mixing Testing Apparatus
Authors: Chohan R. K. , David B. , Nir A. , Tadmor Z. 
Published: December 2013

Abstract
The dispersion process of agglomerated soldis, such as carbon-black, into rubbers and plastics is still not understood to a satisfactory extent. Dispersive mixing is commonly carried out in roll mills, internal mixers and continuous intensive mixers. It is accomplished by repeated passage of the mixture, through converging-tight clearance high stress regions, of the mixers. The key design and operational variables are the geometry of this region, the stress history of the fluid element, and the passage distribution function. A laboratory apparatus was designed and built to enable a systematic study of the effect of these variables on mixing. The apparatus, and experimental results are described. Results verify that the number of passages is a dominant variable in dispersive mixing, and proves the utility of the apparatus to study the dispersive mixing process.
Shear Modification of Polyolefines and its Integration in Polymer Processing
Authors: Ritzau G. 
Published: December 2013

Abstract
The viscous and especially the elastic properties of polymer melts can be altered by a previously imposed deformation history. This phenomenon, usually termed as shear modification, is caused by the reversible physical disentanglement of the polymer molecule chains. The shearing unit presented in this paper was used to systematically investigate the processing parameters governing shear modification.
A set of rheological tests was carried out with the shear modified sample material and the expected changes in the rheological behaviour were detected. The relative change of the storage modulus G', measured using a Rheometrics On-line Rheometer system, was taken as a measure for the degree of modification and was found to correlate with the specific energy dissipated during sample preparation. The effects of shear modification on product properties were investigated for the tubular film-blowing process. Changes in the optical and mechanical properties of films which can be attributed to the previously imposed shear modification process were found.
Shear Flow Properties of Carbon Fibre-Filled Polyethylene Melts
Authors: Kitano T. , Funabashi M. , Klason C. , Kubát J. 
Published: December 2013

Abstract
A fundamental investigation of the influence of fibre loading, fibre length and matrix properties on shear viscosity, complex viscosity and the first normal stress coefficient of filled polyethylene melts prepared by different compounding techniques was carried out. Carbon fibre was compounded into two different types of low-density polyethylene (PEA and PEB) at concentrations up to about 20% by volume using different compounding techniques: a single screw extruder, and a twin screw extruder. The main difference in flow behaviours for the two kinds of carbon fibre-filled systems (CF/PEA and CF/PEB) is not due to differences between the matrix polymers, but due to the difference in fibre length or its distribution caused by the difference in compounding technique. Increasing fibre loading and fibre length increases the shear viscosity and the normal stress coefficient, with the highest increase observed at low shear rates. Especially for longer fibre-filled melts (CF/PEA series) one can estimate the yield stress in the very low shear rate region from the steady shear and dynamic flow data. In the moderate and high shear rate regions the viscosity and normal stress coefficient are influenced greatly by shear flow. Data on the relative viscosities ηr, the relative complex viscosities |η*|r and the relative normal stress coefficients ψr of the two filled systems in the moderate and high shear rate regions were compared with the empirical equation derived previously for ηr for short fibre filled polymer melts. It was found that a form of the expression similar to that obtained previously could describe ηr, |η*|r, and ψr for relatively long carbon fibre filled systems.
Modelling of the Peroxide Degradation of Polypropylene
Authors: Tzoganakis C. , Vlachopoulos J. , Hamielec A. E. 
Published: December 2013

Abstract
A fully-predictive mathematical model has been developed for the peroxide promoted degradation of polypropylene in a plasticating single-screw extruder. The model is based on a free radical kinetic mechanism for the degradation reaction and on conventional plasticating extrusion theory. Solids conveying, melting, melt pumping and reaction phenomena have been combined and the interactions between flow pattern, mass and heat transfer fields via residence time distribution and the chemorheology of the reactive melt have been considered. Given the geometrical configuration of the screw, the operating conditions and the physical properties of the starting polymer, the model can predict: flow rate, pressure, temperature and molecular weight profiles in the extruder channel and in the die, and the residence time distribution in the system. Finally, model predictions are compared with experimental data from runs on a 38mm, 24:1 L/D single-screw extruder using various peroxide concentrations and rotational screw speeds.
Simultaneous Interpenetrating Networks of Polybutadiene-based Polyurethane/Poly (Methyl Methacrylate-co-Glycol Dimethacrylate)
Authors: Jia D. M. , You C. J. , Wu B. , Wang M. Z. 
Published: December 2013

Abstract
Polybutadiene-based polyurethane/poly (methyl methacrylateco-glycol dimethacrylate) interpenetrating polymer networks (PU (HTPB)/P(MMA-co-EGDMA)-IPN) was synthesized by simultaneous polymerization. FTIR and dynamic mechanical spectra (DMS) show no apparent chemical bonds between the two component polymers. The results of DMS also demonstrated that the interpenetration of networks exists mainly between P(MMA-co-EGDMA) and the hard segments of PU(HTPB). The results of transmitting electron microscopy (TEM) indicate that when the amounts of P(MMA-co-EGD-MA) are from 20 to 80 wt%, the domain sizes increase from 100 to 200 Å to several microns, and the morphology features vary from the interpenetration of microphase separation structure to the boundary interpenetration of cellular structure. Besides, the IPN has dual phase continuity. With increasing amounts of P(MMA-co-EGDMA), the stress-strain curves indicate that the corresponding IPN materials transform from reinforced rubbers to toughened plastics. The mechanical properties of the full-IPN are far superior to those of the corresponding linear blends, and also higher than those of the corresponding semi-IPN.
The Processing and Properties of γ-irradiated HDPE Granules
Authors: Bowman J. 
Published: December 2013

Abstract
Granular high density polyethylene has been irradiated to relatively low doses prior to processing. The molecular weight was, at the lower doses, increased and the molecular weight distribution broadened with increasing dose. At the two highest doses an insoluble gel was introduced. These variously irradiated granules were processed by two routes, compression and injection molding, and selected structural features and mechanical properties ascertained. For all granule doses compression molded samples could be produced, with the plaque density decreasing with increasing granule dose. While the ductility of the moldings improved with increasing granule dose, the modulus and yield stress both declined as the density of the moldings decreased. Injection molded samples could only be prepared from granules free of gel. The density of the moldings depended on both granule dose and barrel temperature: in general, the density first increased then declined with increasing granule dose, an effect associated with preferred molecular orientation. The yield stress and modulus both appeared to correlate better with melt flow index rather than density, to infer that preferred molecular orientation is significant in injection moldings and can override the influence of density.
Dynamic Measurements on Polymer Liquid Crystals**
Authors: Horio M. , Kamei E. , Yao S. , Ishikawa S. , Matsunobu K. 
Published: December 2013

Abstract
The dynamic experiments were made on the solutions of poly (l,4-phenylene-2,6-benzobisthioazole) (PBT) in poly(phosphoric acid) at frequencies from 10−2 to 102 radian· sec−1. For the liquid-crystalline solutions, the logarithmic plots of G′ and G″ against frequency show abnormally small slopes and those of η′ exhibit large slopes at low frequencies in contrast to the plots for the optically isotropic solutions. However, the viscoelastic behavior of liquid-crystalline solutions is regarded as linear. The temperature of anisotropic-isotropic phase transition of solution is higher for high-molecular-weight PBT than for lowmolecular-weight PBT. The dilution of solution lowers the transition temperature. The transition goes through various stages of mixed phases. The method of reduced variables is applicable to the isotropic solutions, and the resulted composite curves were discussed. The method, however, is inapplicable to the anisotropic solutions, suggesting that the configuration, interaction and aggregation state of molecules in liquid-crystalline solutions may change sensitively by temperature. The slow relaxation mechanisms are involved in the mesophase systems, but the quick shrinkage of highly oriented nematic mesophase at the onset of relaxation produces the zigzag-fibrillar structure of fibers and films made by stretch spinning or casting.