SPE Library
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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Conference Proceedings
RHEOLOGY AND MELT FRACTURE OF BIODEGRADABLE POLY (?-CAPROLACTONE) POLYESTERS
Nazbanoo Noroozi, Jaclyn A. Thomson, Laurel L. Schafer, Savvas G. Hatzikiriakos, May 2012
The viscoelastic behaviour of a number of commercial and newly synthesized linear biodegradable polyesters - poly (?-caprolactone) (PCLs) with different molecular characteristics was investigated using both rotational and capillary rheometry. The variation of the zero-shear viscosity and relaxation spectrum with molecular weight was studied in detail. The PCL processing instabilities were studied by capillary extrusion using a number of capillary dies having various diameter and length-to- diameter ratios. Sharkskin and gross melt fracture was observed at different shear rates depending on the molecular characteristics of the resins and the geometrical details of the capillary dies.
UNDERSTANDING THE IMAPCT OF PIGMENT LOADING LEVEL ON INJECTION MOLDED COMPONENTS
Shantanu Shivdekar, May 2012
Pigment loading level is one of the most critical factors, governing the properties of the injection molded components. Changing the ratio of the pigment (Colorant) to the base resin could result in failure of the molded component. Material characterization such as Thermo Gravimetric Analysis (TGA) can be conducted to determine the pigment loading level and correlate the failure with functional characteristics of the molded component. Higher concentration of the pigment results in loosing mechanical property of the plastic and thus resulting failure during end use of the product.
DEVELOPMENT OF A METHOD FOR MEASURING THE THERMAL CONTACT RESISTANCE AND THERMAL CONDUCTIVITY OF ELECTRONIC MOLDING COMPOUNDS
Tamas Deak, David Kazmer, Norbert Kovacs, May 2012
The process simulation of thermoset molding processes (e.g. transfer molding, liquid injection molding) becomes increasingly important, because it can significantly reduce the cost of product development. This demands the correct determination of heat transfer and rheological coefficients. The aim of this study was the designing and construction of an apparatus which can measure the thermal contact resistance and thermal conductivity of epoxy molding compounds in the same circumstances which they encounter during processing.
ELECTROMAGNETIC INDUCTION COIL DESIGN FOR MOLD SURFACE HEATING
Ming-Shyan Huang, Sheng-Wei Tsai, Je-Wei Lian, Shih-Chih Nian, May 2012
The objective of this study is to find an optimal design of electromagnetic induction coil for mold surface heating. To simulate the temperature distribution of mold surface in the induction heating process, the commercial software of COMSOL Multiphysics is employed. Design parameters such as induction coils include coil diameter, heating distance, coil space, and electromagnetic induction frequency are considered in this research. The Taguchi method is used to analysis the effects of process parameters on the mold surface temperature distribution and heating rate. The simulation shows that: (1) coil diameter and coil space are the most significant parameters of affecting heating rate and temperature uniformity. (2) Small coil diameter increases the heating rate but results in non-uniform heating temperature. (3) Short heating distance is helpful for the heating rate but creates worse temperature variation. (4) Small coil space results in fast heating rate but generates significant temperature difference. (5) High induction frequency facilitates heating rate.
NANO-COMPOSITES CHARACTERIZATION BY HYPER DIFFERENTIAL SCANNING CALORIMETRY (HYPERDSC)
Andrew W. Salamon, Dave Norman, May 2012
Thermal analytical techniques that are used to characterize nanocomposite formulations. Differential Scanning Calorimetry (DSC, HyperDSC™), Thermogravimetry (TGA), Dynamic Mechanical Analysis (DMA), and the hyphenated technique Thermogravimetry-Gas Chromatography-Mass Spectrometry (TGA-GC-MS), are used to measure nanocomposites. These measurements help ensure that the nanocomposite manufacturing process is stable, reproducible, and reliable. This poster concentrates on the formulation and end product validation through Differential Scanning Calorimetry (HyperDSC™) characterization of the rigid and mobile amorphous fractions of a nanocomposite.
CHARACTERIZATION OF TENSILE PROPERTIES OF FUSED DEPOSITION MODELLING PROCESSED ABS MATERIAL
Prabin Kumar Chaudhary, S.H. Masood, May 2012
This paper presents the tensile properties of ABS parts fabricated by Fused Deposition Modeling rapid prototyping process. The mechanical behavior of FDM processed ABS parts for engineering applications is dictated by the FDM process parameters. This paper characterizes the tensile properties of ABS parts considering process parameters such as air gap, raster width, raster angle and build orientations. The tensile properties of FDM processed ABS parts are compared with that of injection molded ABS parts.
USING SIMULTANEOUS DSC-RAMAN TECHNOLOGY TO STUDY CRYSTALLIZATION OF NYLON 6
Richard Spragg, Geert van den Poel, Lilian Willems, Enrique lozeno Diz, Peng Ye, May 2012
Nylon 6 (polycaprolactam) is a polyamide that is widely used in the form of fibers. There are two crystalline forms, ? and ?. The common ? form has a fully extended planar zigzag conformation. The ? form differs in the hydrogen bonding between chains which produces a twisted gauche conformation about the C-N bond of the amide group. This change in conformation leads to significant differences in the Raman spectra of the two forms. The crystallization behavior of nylon-6 is known to differ between virgin and previously extruded material. DSC measurements show that crystallization from the melt occurs at about 173°C for virgin material but at about 185°C for samples that have previously been extruded. Combined Raman and DSC measurements provide different insights into thermally induced phase changes. In the case of semi-crystalline materials Ramandata gives qualitative information about molecular conformations to complement the purely quantitative information from DSC. We have used this approach to study crystallization in nylon-6.
CO-ROTATING FULLY INTERMESHING TWIN-SCREW COMPOUNDING EXTRUDERS: ADVANCEMENTS FOR IMPROVED PERFORMANCE AND PRODUCTIVITY
Paul G. Andersen, Frank Lechner, May 2012
The co-rotating fully intermeshing twin-screw extruder is the primary production unit for compounding of polymer based materials. It also has had a long term presence in processing material in the chemical and food industry and more recently in pharmaceuticals. While this equipment celebrated its 50th anniversary several years ago and might be considered a “mature” technology, it has not experienced a decline in new developments as might be expected, but rather a significant number of advancements continue to evolve. This paper will highlight several significant developments of the past 10 to 15 years. These are the implementation of high torque (power) designs, the use of increased rpm in conjunction with high torque for improved operating flexibility and productivity, and finally a technology breakthrough for feeding difficult to handle low bulk density materials.
EFFECT OF NANOCLAYS ON THE COMPATIBILITY OF MALEIC ANHYDRIDE-GRAFTED-POLYPROPYLENE/POLY (ETHYLENE OXIDE) BLEND
Abdulhadi A. Al-Juhani, May 2012
This study investigated the effect of surface modification of nanoclays on the compatibility of Maleic Anhydride-grafted polypropylene (PP-g-MA)/poly (ethylene oxide) (PEO) blends. Rheological testing confirmed the network formation of nanaoclays of all types. SEM confirmed the emulsifying role of nanoclays by reducing the PEO domain size. For the case of using dialkyl (C18)-modified nanoclays, mechanical testing showed that the elastic modulus and the toughness were respectively improved by 20% and 55% compared to unfilled samples.
TEMPERATURE DEPENDENCE OF THE INTERFACIAL SHEAR STRENGTH IN GLASS–FIBER POLYPROPYLENE COMPOSITES INVESTIGATED BY A NOVEL SINGLE FIBER TECHNIQUE
James L. Thomason, Liu Yang, May 2012
To obtain information on the temperature dependence of the interfacial strength (IFSS) in glass – polypropylene composites a thermomechanical analyser was adapted to enable microbond testing to be carried out in a well controlled temperature environment. Test results obtained by TMA-microbond testing showed excellent comparability with those obtained by normal microbond testing. The of IFSS of glass – polypropylene was measured from -40°C up to 100°C. The IFSS showed a highly significant inverse dependence on testing temperature.
ENVIRONMENTAL STRESS CRACKING OF A POLY(ACRYLONITRILE:BUTADIENE:STYRENE) CUP HOLDER
Christelle F. Poquette, Niles G. Stenmark, May 2012
Environmental stress cracking (ESC) resistance has become an essential industrial criterion for engineering thermoplastics, as ESC causes unexpected brittle fracture of ductile amorphous plastics. In the automotive industry, a variety of amorphous plastics are used, which need to be ESC resistant, as they come in contact with various fluids while subjected to mechanical stresses. PC-ABS materials offer a good compromise between processibility, cost and mechanical properties. However, this material is prone to ESC failure.
COMPOUNDING EXTRUSION OF POLYPROPYLENE CARBON NANOTUBE COMPOSITES: OPTIMISING AND ECONOMIZING PROCESS WITH A COMMERCIAL PERSPECTIVE – A CASE STUDY
Daniel Berkowitz Zamora, Shyam Sathyanarayana, Patrick Weiss, Christof Hübner, Jan Diemert, Frank Henning, Peter Elsner, May 2012
Compounding extrusion of Polypropylene-Carbon nanotube composite is presented as a case study with Design of Experiments approach to identify best processing parameters for optimum dispersions and conductivity. Influence of Specific Mechanical Energy input on resulting morphology and volume resistivity of extruded strands are analyzed with statistical viewpoints. Resistances of the melt are measured with an online process monitoring approach and correlated with measurements on extruded strands. This aids process planning, and economization.
INVESTIGATIONS OF THE BRITTLE FAILURE CAUSED BY AN ENVIRONMENTAL STRESS CRACKING OF A PLASTIC ENCLOSURE
Ahamed Shabeer, Gerald F. Zamiski, May 2012
The causes of a drastic reduction in the service life of plastic enclosures molded from an acrylonitrilebutadiene- styrene (ABS) resin have been investigated. The mechanism and type of failure have been deduced from a detailed morphological examination of the fracture surface. Various factors responsible for a rapid failure of the enclosure have been identified. Analytical testing such as infrared spectroscopy and differential scanning calorimetry were performed to identify a specific material characteristic responsible for the failure. The results obtained during the evaluation indicated that the failure was due to environmental stress cracking, which occurred as a consequence of the presence of an incompatible chemical and assembly stress. The nature of the chemical agent was found and its effect on the properties of the ABS is discussed.
FLOW BEHAVIOR OF DIFFERENT POLYETHYLENES IN CAPILLARY FLOW
Evan Mitsoulis, Thanasis Zisis, Mahmoud Ansari, Savvas G. Hatzikiriakos, May 2012
Three major polyethylene (PE) engineering plastics, linear-low-density (LLDPE), low-density (LDPE) and high- density (HDPE) are studied in capillary flow. The purpose is to find experimentally and predict numerically their flow behaviour, namely the pressure drop in flow through tapered dies. This behavior is related to their individual rheological and flow properties. Using a series of capillary dies having different diameters D and length-to-diameter L/D ratios, a full rheological characterization has been carried out, and the experimental data have been fitted with the viscoelastic K-BKZ/PSM model. The branched LDPE has a strong pressure-dependence of viscosity, with a pressure-dependent coefficient ?p. For the linear LLDPE and HDPE melts, the pressure-dependence of viscosity is weak, but slip at the wall is strong and affects their flow behaviour. Thermal effects due to viscous dissipation are included but are rather mild. It is found that the viscoelastic simulations are capable of reproducing the experimental data well, in the whole range of apparent shear rates and L/D ratios.
SOME ISSUES ARISING IN FINDING THE DETACHMENT POINT IN CALENDERING OF PLASTIC SHEETS
Evan Mitsoulis, May 2012
Calendering is a process for producing plastic sheets of a desired final thickness and appearance. The thickness of the exiting sheet during a calendering operation is uniquely found by the Lubrication Approximation Theory (LAT) and the application of the Swift boundary conditions, which dictate that both the pressure and its axial derivative are zero at detachment. This cannot be used in a 2-D analysis of the process, where the detachment point is the anchor of a free surface, and hence a singular point where both the pressure and the stresses go through numerical oscillations. This difficulty can be circumvented by using the Boundary Element Method (BEM), which uses as primary variables velocities and tractions, and thus avoids pressures and stresses. Then the detachment point is found as the point where the tangential traction becomes zero. Numerical tests undertaken here with the Finite Element Method (FEM) show that the LAT results can be used as a good approximation for the detachment point, which is then fixed. Comparisons with 2-D BEM results show a good agreement for all flow field variables. However, the exact position of the detachment point in a 2-D FEM analysis is still elusive, since for viscous polymer melts the contact angle is not known and should be part of the solution. Some thoughts are given about how to tackle this still unresolved issue, based on double nodes with discontinuous velocities and pressures.
MISCIBILITY CHARACTERIZATION OF INDOMETHACIN AND EUDRAGIT® E PO BY RHEOLOGICAL AND THERMAL ANALYSIS
Huiju Liu, Herman Suwardie, Xueyan Zhang, Peng Wang, Costas G. Gogos, May 2012
The miscibility between drug indomethacin and excipient Eudragit® E PO were extensively characterized by rheological and thermal analysis. The evolution of glass transition temperature and activation energy with indomethacin concentration indicates the existence of overall positive deviation which represents anti-plasticization effect. The rheological analysis is in agreement with the thermal analysis, and both methods indicate that the miscibility between them is very good for indomethacin concentrations up to 60~70%.
CHARACTERISTIC OPTIMIZATION OF ELECTRICALLY CONDUCTIVE INJECTION-MOLDED PARTS USING THE EXAMPLE OF HIGH TEMPERATURE BIPOLAR PLATES
Johannes Wortberg, Marco Lenzen, Georg Lenze, May 2012
Topic of this article is the result of some investigations which are representing the foundations for quality optimization of highly filled injection-molded parts, represented by the electrical conductivity. In this context the influence of the process conditions on the electric conductivity of high temperature bipolar plates is subject of research. Especially the cavity pressure, the melt temperature and the time dependence of these values became essential.
INTEGRATED STORAGE ACTUATOR MODULE FOR CONTINUOUS POWER CONSUMPTION IN PERIODIC PROCESSES
Johannes Wortberg, Marco Lenzen, May 2012
The injection molding process is widely known as one of the most advanced processes for manufacturing of parts that range from simple commodities to accurate technical parts. Due to the cyclical process the power consumption is highly discontinuous causing distinct peak power. This article describes an alternative local drive concept, which is able to realize a continuous power consumption during the injection molding process. This concept is designed for tasks with a high power demand, for example clamping forces about 13.000 kN.
BLOWN FILMS OF NANOCOMPOSITES PREPARED FROM ORGANOCLAY/COPPER-NANOPARTICLE POLYPROPYLENE
Pitchaya Naneraksa, Ratanawan Magaraphan, May 2012
Polypropylene blown film containing 1 wt% nanoparticles was fabricated which organoclay and copper nanoparticles were incorporated for barrier and antimicrobial purpose. Effect of copper nanoparticle content (5, 10, 15 and 20 wt% of total nano-fillers) on clarity and mechanical properties of polypropylene nanocomposite film was investigated. Nanocomposite PP films were fabricated via water-quenched blown film extrusion. A sodium neutralized ethylene-methacrylic acid ionomer of 2 phr was used to modify compatibility between polypropylene and nano-fillers.
LIGHT SCATTERING ANALYSIS OF POLYETHYLENE BLOWN FILMS: RELATIONSHIPS BETWEEN INTERNAL HAZE AND MORPHOLOGY
Lizhi Liu, Teresa P. Karjala, Xuming Chen, Jian Wang, Mehmet Demirors, Selim Bensason, May 2012
The morphological basis of improvements in film haze achieved by blending LDPE into LLDPE was explored with light scattering. Two-dimensional light scattering patterns were analyzed by a novel approach to define a “Morphology Index”. Besides its utility as a numeric descriptor of the superstructure in the continuum from spherulitic to fibrillar morphologies, the Morphology Index was also found to correlate well with the internal haze of films.
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