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
IMPROVING BLOWN FILM YIELD BY REDUCTION OF RESIN USED TO COVER PROCESS SHORTCOMINGS
Daniel R. Joseph, May 2010
This paper introduces the concept of improving blown film yield by reducing excess resin being used to cover chronic gauge problems and manual width control methods. The term runaway resin is introduced and quantified for manual width control. A case study is presented that demonstrates reductions in runaway resin and yield improvement by adding an easy to install width control system to a basic 405mm die (without internal bubble cooling) running commodity products.
REVIEW PAPER: PROCESSING ASPECTS OF HOT MELT EXTRUSION IN PHARMACEUTICAL APPLICATIONS
Huiju Liu , Peng Wang , Marino Xanthos , Linjie Zhu , Costas G. Gogos, May 2010
Applying extrusion technology to drug manufacturing received increasing attention in the last two decades. Extrusion technology has the potential of replacing current pharmaceuticals manufacturing methods due to the advantages such as the elimination of solvent and the continuous and consistent high throughput. This article presents a brief review of Hot Melt Extrusion (HME) from polymer processing perspective, concentrating on mixing, material degradation and process analytical technology.
SIMULATION OF DISTRIBUTIVE AND DISPERSIVE MIXING IN A CO-ROTATING TWIN-SCREW EXTRUDER
L. Cong , M. Gupta, May 2010
Simulation results for mixing of two different polymers in a co-rotating twin-screw extruder are presented. Velocity distribution predicted by a threedimensional simulation of the flow is used to predict the change in the spatial distribution of initially segregated particles as well as the reduction in radius due to erosion.The predicted particle distribution is used to estimate the increase in Shannon entropy due to dispersive and distributive mixing along the extruder channel.
EXTRUSION FOAMING OF POLYMER NANOCOMPOSITES WITH DISTINCT STRAIN HARDENING CHARACTERISTICS
Amit K. Chaudhary, Krishnamurthy Jayaraman, May 2010
Thermoplastic foams were produced from two different polypropylene nanocomposites by extrusion with the help of a chemical blowing agent. The strain hardening ratio decreased with increasing strain rate for one of the nanocomposites. For the other nanocomposite melt, the strain hardening ratio was unchanged with strain rate. Smaller cell sizes (less than 40 microns in diameter) were obtained when the nanocomposite melt displayed strain hardening levels in extensional flow that were maintained over a range of strain rates.
STUDY ON MORPHOLOGY, CRYSTALLINITY, BARRIER AND MECHANICAL PROPERTIES OF PET NANOCOMPOSITE FILMS
Gowrishankar Srinivasan, David Grewell,, May 2010
Polyethylene terephthalate (PET) nanocomposite films were prepared by cast extrusion followed by stretching, using chill rolls. Tensile modulus, tear and puncture resistance of the cast films were measured in the machine (MD) and transverse (TD) directions. Differential scanning calorimetry (DSC) was used to study the effect of processing conditions on crystallinity of the products. Effects of draw ratio and clay content on the mechanical properties and on the oxygen permeability of the PET nanocomposite films were also evaluated.
NON-ISOTHERMAL SIMULATION OF THE FLOW IN CO-ROTATING AND COUNTER-ROTATING TWIN-SCREW EXTRUDERS USING MESH PARTITIOING TECHNIQUE
Mahesh Gupta, May 2010
A new algorithm for simulation of non-isothermal flow in a twin-screw extruder is introduced. In the new algorithm the finite element mesh of tetrahedral elements is created in the complete barrel including the space occupied by the screws. By partitioning the tetrahedral elements which are intersected by the screw surfaces into two tetrahedral pyramidal or prismatic finite elements the new algorithm allows the flow simulation in twinscrew extruder without regenerating the finite element mesh as the two screws rotate.
FLAMMABILITY OF FR-PP BASED SANDWICH INJECTION MOLDINGS
Makoto Seino , Manabu Nomura , Masaya Kotaki, May 2010
Flammability of frame retardant polypropylene (FR-PP) based sandwich injection moldings was investigated. Flame-retardant and filler were intentionally incorporated in the skin and the core parts of sandwich injection moldings. Sandwich injection moldings showed superior flame retardancy and mechanical properties when high contents of flame-retardant and filler were incorporated in the skin and the core parts respectively. This trend was remarkable when phosphorous flame-retardant (Intumescent) was used compared to bromine flame-retardant.
FLAMMABILITY OF FR-PP BASED SANDWICH INJECTION MOLDINGS
Makoto Seino , Manabu Nomura , Masaya Kotaki, May 2010
Flammability of flame retardant polypropylene (FR-PP) based sandwich injection moldings was investigated. Flame-retardant and filler were intentionally incorporated in the skin and the core parts of sandwich injection moldings. Sandwich injection moldings showed superior flame retardancy and mechanical properties when high contents of flame-retardant and filler were incorporated in the skin and the core parts, respectively. This trend was remarkable when phosphorous flame-retardant (Intumescent) was used compared to bromine flame-retardant.
IMPROVEMENT IN SURFACE QUALITY OF MICROCELLULAR INJECTION MOLDED PARTS
Jungjoo Lee , Lih-Sheng Turng, May 2010
Microcellular injection molding has many advantages such as cost savings reduced cycle times and excellent shrinkage properties. However surface defects on the microcellular injection molded parts—such as gas-flow swirl marks and a lack of smoothness—still remain a challenge. This paper describes a method to improve the surface quality of microcellular injection molded parts.
IMPROVEMENT IN SURFACE QUALITY OF MICROCELLULAR INJECTION MOLDED PARTS
Jungjoo Lee , Lih-Sheng Turng, May 2010
Microcellular injection molding has many advantages such as cost savings, reduced cycle times, and excellent shrinkage properties. However, surface defects on the microcellular injection molded partsƒ??such as gas-flow swirl marks and a lack of smoothnessƒ??still remain a challenge. This paper describes a method to improve the surface quality of microcellular injection molded parts.
BATCH FOAMING OF GLASS FIBER REINFORCED WOOD PLASTIC COMPOSITES
Hamid O. Semeralul , Ghaus M. Rizvi , Mohammad Rubyet Islam, May 2010
Foaming of wood plastic composites (WPC), along with the addition of small amounts of glass fiber can improve the mechanical properties of WPC. Such improvements have the potential to help WPC find applications in areas where it has been previously overlooked due to factors such as its low strength and high density when compared with natural wood. The foaming process involves many parameters that interact to determine the quality of the final product. This paper investigates some of these parameters with the aim of optimizing them.
CHARACTERIZATION OF PROPERTIES OF WOOD PLASTIC COMPOSITES (WPC) WITH GLASS FIBER REINFORCEMENTS
Hamid O. Semeralul , Ghaus M. Rizvi, May 2010
The mechanical properties of wood plastic composites (WPC) can be improved with the addition of small amounts of glass fiber. This improvement can help WPC find applications in areas where it has been previously overlooked due to factors such as its lowstrength when compared with natural wood. Mechanical properties such as flexural and impact strength showed improvements upon the addition of glass fibers (GF) in certain compositions. This paper examines the effects of GF upon these properties.
FINITE ELEMENT MODELING AND MICROSTRUCTURE ANALYSIS FOR CONTOUR LASER TRANSMISSION WELDING OF GLASS FIBRE REINFORCED NYLON 6
M. Chen , G. Zak , P.J. Bates , M.R. Kamal , M. Al-Wohoush, May 2010
This paper presents FEM heat transfer analysis and experimental results for contour laser transmission welding of glass fibre reinforced Nylon 6. Predicted temperature fields near the weld interface were compared with the dimensions of the heat affected zone, and weld widths. Temperature profiles at the weldline were also estimated from the modeling data.
STUDY ON THE SHEAR VISCOSITY OF HDPE-WOOD COMPOSITES/SUPERCRITICAL CO2 SOLUTION
Jingjing Zhang , Jing Wang , Chul B. Park , Ghaus M. Rizvi , Han-Xiong Huang, May 2010
In this work the shear viscosities of wood plastic composites (WPC)/ supercritical CO2 (sc-CO2) solutions at different die temperatures and sc-CO2 contents were measured by a slit die attached on a single-screw extrusion system. A theoretical model based on the Cross-Yasuda model and Arrhenius equation was developed to describe the shear-thinning behavior of the WPC/ sc-CO2 solution. The model was a function of temperature pressure sc-CO2 content and shear rate.
STUDY ON THE SHEAR VISCOSITY OF HDPE-WOOD COMPOSITES/SUPERCRITICAL CO2 SOLUTION
Jingjing Zhang , Jing Wang , Chul B. Park , Ghaus M. Rizvi , Han-Xiong Huang, May 2010
In this work, the shear viscosities of wood plastic composites (WPC)/ supercritical CO2 (sc-CO2) solutions at different die temperatures and sc-CO2 contents were measured by a slit die attached on a single-screw extrusion system. A theoretical model based on the Cross-Yasuda model and Arrhenius equation was developed to describe the shear-thinning behavior of the WPC/ sc-CO2 solution. The model was a function of temperature, pressure, sc-CO2 content, and shear rate.
VIBRATION WELDING POLYPROPYLENE – EFFECT OF MFI ON WELD STRENGTH AND MICROSTRUCTURE
P.J. Bates , A. Powell, May 2010
This paper examines the weld strength and microstructure of three polypropylene homopolymers of different melt flow indices (MFI). The heat affected zone thickness was observed to be inversely proportional to weld pressure and polymer MFI. The weld strength was observed to decrease with pressure. The weld strengths of lower MFI polymers were more weld-pressure sensitive.
VIBRATION WELDING POLYPROPYLENE ƒ?? EFFECT OF MFI ON WELD STRENGTH AND MICROSTRUCTURE
P.J. Bates , A. Powell , M. Kontopoulou, May 2010
This paper examines the weld strength and microstructure of three polypropylene homopolymers of different melt flow indices (MFI). The heat affected zone thickness was observed to be inversely proportional to weld pressure and polymer MFI. The weld strength was observed to decrease with pressure. The weld strengths of lower MFI polymers were more weld-pressure sensitive.
THE INFLUENCE OF THE PROCESSING CONDITIONS ON THE PS/MWCNT COMPOSITES PREPARED WITH TWIN SCREW EXTRUDER
Jian-Kang Wang, Xiang-Yang Liu , Han-Xiong Huang, May 2010
Polystyrene/multi-wall carbon nanotube composites, PS/MWCNT, were prepared with co-rotating twin screw extruder. PS/MWCNT was prepared by diluting highly concentrated MWCNT masterbatch chips. We investigated rheological and mechanical properties of PS/MWCNT composites. Rheological and mechanical properties of PS/MWCNT composites depended on concentration of PS/MWCNT and processing conditions such as screw speed, feeding rate.
NATURAL FIBER-PHENOLIC-HANNEBACHITE COMPOSITES: EFFECTS OF FIBER TYPE
Hui Deng , John M. Torkelson, May 2010
The management of greenhouse gasses can certainly benefit from better marshalling of our wooded lands. Therefore, our recent research has focused on developing wood-substitute composites without wood in them from natural fibrous materials, e.g., jute, miscanthus, kenaf, wheat straw, and industrial hemp and plate-like hannebachite crystallites. Imaging, DSC, flexural strength and water sensitivity measurements were undertaken on composites formulated from the aforementioned natural fibers. Comparative effects on the mechanical and thermal properties were ascertained.
3D SIMULATIONS OF A REACTIVE FLOW IN SCREW ELEMENTS OF CLOSELY INTERMESHING TWIN SCREW EXTRUDERS: CONVENTIONAL AND VARIABLE SPEED EXTRUDERS
Babu Padmanabhan, Chetan Chincholi Jayanth, May 2010
The peroxide-initiated degradation of polypropylene in conveying screw elements of closely intermeshing twin screw extruders (COITSEs) is analyzed by means of a three-dimensional (3D) simulation approach. The simulations are implemented for a conventional and a special design screw element (from a variable speed extruder). Different values of peroxide concentrations and mass throughputs are implemented to analyze the reactive system of interest in terms of the specified extruder design.
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