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

COMPUTER SIMULATION FOR FLOW BEHAVIOR ON MICRO- AND NANO-MOLDING

Kazumi Tada , Daisuke Fukuzawa , Ayako Watanabe , Hiroshi Ito, May 2010

3-dimensional FEM simulation was performed to clarify the mechanism on surface replication in micro-injection molding and thermal nano-imprinting.Especially the filling behavior into micro- and nanosurface features was discussed in comparison with the experimental results. The simulation results and the experimental results of injection molding show possibility of the generation of air traps in the filling stage and it is considered that those air traps have a strong relation with replication shape and replication rate. The simulation results of thermal imprinting clarified penetration behavior of polymer melt into nano-surface feature and show that the aspect ratio of the cavity and imprinting pressure influenced flow behavior in thermal imprinting.

ELASTIC RECOVERY BEHAVIOR OF THREE LAYER FILM STRUCTURES COMPRISED OF TPO AND VARIOUS ETHYLENE COPOLYMERS

Christopher Shelley , Nicolas Kokel, May 2010

Stretch hood films used to protect and unitize pallet loads are becoming more sophisticated structures that combine the unique properties of several advanced polymers. The combined properties of reactor TPO resins and ethylene copolymers will continue to expand the envelope of application and performance possibilities for film engineers delivering enhanced strength and pallet security heat resistance extensibility elastic recovery and material use reduction. This paper will discuss the relationships between film formulation and degree of orientation on the elastic and physical properties of a three-layer stretch hood film structure.

ELASTIC RECOVERY BEHAVIOR OF THREE LAYER FILM STRUCTURES COMPRISED OF TPO AND VARIOUS ETHYLENE COPOLYMERS

Christopher Shelley , Nicolas Kokel, May 2010

Stretch hood films used to protect and unitize pallet loads are becoming more sophisticated structures that combine the unique properties of several advanced polymers. The combined properties of reactor TPO resins and ethylene copolymers will continue to expand the envelope of application and performance possibilities for film engineers, delivering enhanced strength and pallet security, heat resistance, extensibility, elastic recovery, and material use reduction. This paper will discuss the relationships between film formulation and degree of orientation on the elastic and physical properties of a three-layer stretch hood film structure.

IMPROVEMENT OF THE MECHANICAL PROPERTIES OF THERMOPLASTIC FOAMS THROUGH MODIFICATION OF THE FOAM STRUCTURE

Walter Michaeli , Laura Flórez , Dominik Obeloer , Markus Brinkmann, May 2010

Foaming an injection molded thermoplastic part can reduce its weight warpage and the associated processing costs but it also results in a loss of mechanical performance. This loss can however be mitigated through specific modifications of the foam structure while at the same time the material consumption is minimized. This paper analyzes the changes that are induced by foaming in the mechanical performance of thermoplastic materials and demonstrates the gain in mechanical strength that can be achieved by inducing modifications of the foam structure for example in the skin thickness the mean cell size and the foam density.

IMPROVEMENT OF THE MECHANICAL PROPERTIES OF THERMOPLASTIC FOAMS THROUGH MODIFICATION OF THE FOAM STRUCTURE

Walter Michaeli , Laura Flórez , Dominik Obeloer , Markus Brinkmann, May 2010

Foaming an injection molded thermoplastic part can reduce its weight, warpage and the associated processing costs, but it also results in a loss of mechanical performance. This loss can, however, be mitigated through specific modifications of the foam structure, while at the same time the material consumption is minimized. This paper analyzes the changes that are induced by foaming in the mechanical performance of thermoplastic materials and demonstrates the gain in mechanical strength that can be achieved by inducing modifications of the foam structure, for example in the skin thickness, the mean cell size and the foam density.

APPLICATIONS OF HIGH-FREQUENCY INDUCTION HEATING TO HIGH-QUALITY INJECTION MOLDING

Nathan Tortorella, Charles L. Beatty, May 2010

High-frequency induction heating is an efficient way to rapidly heat mold surface by utilizing a high-frequency skin effect. Because the procedure allows for the rapid heating and cooling of mold surfaces, it has been recently applied to the injection molding in various purposes. The present work introduces various industrial applications of high-frequency induction heating to high-quality injection molding including: (i) moldability improvement in thin-wall injection molding, (ii) improvement of replication ratio of micro-features, and (iii) remove of weldlines for a mobile phone cover which contains multiple holes.

UNIQUE CRYSTALLINE NATURE OF A HIGH IMPACT STRENGTH POLYPROPYLENE ALLOY

Nathan Tortorella , Charles L. Beatty, May 2010

Isotactic polypropylene (PP) has been reactivelyblended with an ethylene-octene copolymer (EOC) in atwin screw extruder. Free radical polymerization ofstyrene and a multifunctional acrylate during meltextrusion has resulted in an enhancement of mechanicalproperties and discovery of unique features in bothamorphous and crystalline phases. DSC indicates thatsmall lamellar crystals are present in the reacted blends which melt and recrystallize in a much different mannercompared to ungrafted PP. XRD reinforces DSC resultsin that the size and perfection of the alpha crystallinephase are reduced by grafting. SEM shows a uniquecross-hatch structure as indicated by XRD. Polarizedlight microscopy gives evidence that grafting andbranching within the reacted blend causes a gelation-likerecrystallization.

DURABILITY OF NATURAL FIBER SHEET MOLDING COMPOUND (ECO-SMC)

Masaharu Nishiura , Makoto Sarata , Yuya Hidekuma , Masanori Okano , Asami Nakai , Hiroyuki Hamada, May 2010

Recent earth environmental concern requires easy recycle material system and the use of biodegradable polymer and natural fiber is noticed in composite materials. To apply the natural fiber for the structural parts the use as reinforcement of Sheet Molding Compound (SMC) is desirable because it is expected that SMC can be used in various fields in terms of high productivity and dimensional stability. Considering that fiber reinforced composite is used for structural part the use of long-span must be possible. Therefore the evaluation of the durability such as degradation is very important subject. In this study SMC (Sheet Molding Compound) that reinforcement was jute cloth were prepared. The jute cloth reinforced SMC was immersed in hot water to promote the degradation. And after immersion an increase ratio of water and bending properties were compared with that of jute cloth reinforced SMC without immersion. As a result the fracture mechanism changed from the combination of crack propagation in matrix area and delamination in the interface around the fiber bundle to only crack propagation in matrix area by water immersion.

Durability of Natural Fiber Sheet Molding Compound (Eco-SMC)

Masaharu Nishiura , Makoto Sarata , Yuya Hidekuma , Masanori Okano , Asami Nakai , Hiroyuki Hamada, May 2010

Recent earth environmental concern requires easy recycle material system, and the use of biodegradable polymer and natural fiber is noticed in composite materials. To apply the natural fiber for the structural parts, the use as reinforcement of Sheet Molding Compound (SMC) is desirable because it is expected that SMC can be used in various fields in terms of high productivity and dimensional stability. Considering that fiber reinforced composite is used for structural part, the use of long-span must be possible. Therefore, the evaluation of the durability such as degradation is very important subject. In this study, SMC (Sheet Molding Compound) that reinforcement was jute cloth were prepared. The jute cloth reinforced SMC was immersed in hot water to promote the degradation. And after immersion, an increase ratio of water and bending properties were compared with that of jute cloth reinforced SMC without immersion. As a result,the fracture mechanism changed from the combination of crack propagation in matrix area and delamination in the interface around the fiber bundle to only crack propagation in matrix area by water immersion.

HYDROPHOBIC-MODIFIED CELLULOSE FIBERS AND CELLULOSE MICROFIBRILAS REINFORCEMENTS FOR BIOCOMPOSITES

Wilailak Chanklin , Shuzhao Li , Huining Xiao, May 2010

The hydrophobic modification of cellulose fiber (CF) and cellulose microfibril (CMF) was conducted by grafting 1'Octadecanol using TDI as a coupling agent. The optimum reaction conditions obtained for grafting were: molar ratio of cellulosic materials:1'Octadecanol:TDI 1:1:1 (molar ratios of OH groups in fibers and reactive groups in reagents), temperature of reaction 120?øC and reaction time 3 h. The grafting was confirmed by FT-IR; and TGA measurement indicated that the amounts of grafting were 16.9wt% and 13.9wt% for CF and CMF,, respectively. Moreover, the surface morphology and hydrohphobicity of the grafted fibers were investigated by SEM and static contact angle measurement.

FOAMING OF LDPE/SILICA NANOCOMPOSITES: IMPROVING THE CELLULAR STRUCTURE AND MECHANICAL PROPERTIES

M.A. Rodriguez-Perez , P. Garcia de Acilu Laa , J. Arevalo-Guiterrez , C. Saiz-Arroyo , E.Solorzano , J.A. de Saja, May 2010

Low density polyethylene/nano-silica nanocomposites has been foamed using an improved compression molding process. Different amounts of nanosilica (from 1 to 9 % by weight) were used. A high level of particle dispersion was achieved both in the solid precursor and in the foams. It was found a significant increment of the mechanical properties both in solids and foams; being the increase in properties more significant in the foams. A reduction in cell size has been observed with the addition of nanosilica. Cell sizes in the microcellular range were obtained.

FOAMING OF LDPE/SILICA NANOCOMPOSITES: IMPROVING THE CELLULAR STRUCTURE AND MECHANICAL PROPERTIES

M.A. Rodriguez-Perez , P. Garcia de Acilu Laa , J. Arevalo-Guiterrez , C. Saiz-Arroyo , E.Solorzano , J.A de Saja, May 2010

Low density polyethylene/nano-silica nanocomposites has been foamed using an improved compression molding process. Different amounts of nanosilica (from 1 to 9 % by weight) were used. A high level of particle dispersion was achieved both in the solid precursor and in the foams. It was found a significant increment of the mechanical properties both in solids and foams; being the increase in properties more significant in the foams. A reduction in cell size has been observed with the addition of nanosilica.Cell sizes in the microcellular range were obtained.

MECHANICAL HOLE BURNING SPECTROSCOPY IN POLYMERIC SYSTEMS - A NOVEL TECHNIQUE TO CHARACTERIZE DYNAMIC HETEROGENEITY

Philip Jacoby, May 2010

Mechanical Spectral Hole Burning (MSHB) is a novel rheological technique to probe dynamic heterogeneity for polymeric materials, which exhibit relatively weak dielectric responses. In the present work, mechanical spectral hole burning (MSHB) was applied to a block copolymer and a series of polystyrene solutions in order to investigate its capability of detecting the heterogeneity and the possible relationship between the length scale of heterogeneity and hole properties. The results illustrate the power of MSHB to probe the dynamic heterogeneity of polymeric systems as evidenced by the presence or absence of mechanical holes in the vicinity of the order-disorder transition of a block copolymer. The results also suggest the hole properties are not governed by the length scale of the heterogeneity, rather they are dominated by the dynamics, i.e., whether the MSHB is performed in close to Rouse regime, rubbery plateau regime, transition regime from plateau to terminal region or the terminal flow regime.

LONG TERM POLYURETHANE CATHETER ALCOHOL COMPATIBILITY I, PHYSICAL AND RHEOLOGICAL STUDIES

W. Michaeli, Sebastian Hessner, Fritz Klaiber, May 2010

Thermoplastic urethanes (TPU) offer broad property range, processing flexibility, and biocompatibility for medical applications. Alcohol based disinfectants have a long history of effective and safe use. Expanding on earlier rheology molecular weight data indicating minimal reduction, we conducted a long term compatibility study covering all known urethane types in a hemo-dialysis setting with a simulated clinical exposure protocol for 90 days. After 90 days exposure, minor changes in physical properties on the catheter body and components were detected, often similar to the saline control. Most importantly, resultant properties far exceeded ISO requirements for catheters.

QUALITY ANALYSIS OF INJECTION-COMPRESSION MOULDED OPTICAL LENSES

W. Michaeli , Sebastian Hessner , Fritz Klaiber, May 2010

The manufacturing of optical components by injection moulding and injection-compression moulding is a serious challenge for mould and machine technology as well as for process control. Polymer lenses were manufactured with a modularly designed injectioncompression mould base thus different injectioncompression moulding technologies could be examined. To evaluate the quality of optical parts the accuracy of the moulded geometry as well as the resulting optical performance has been analysed. At present a geometrical moulding accuracy in the lower micron range has been achieved. Overall injection-compression moulded lenses showed a better optical performance than injection moulded lenses.

QUALITY ANALYSIS OF INJECTION-COMPRESSION MOULDED OPTICAL LENSES

W. Michaeli , Sebastian Hessner, May 2010

The manufacturing of optical components by injection moulding and injection-compression moulding is a serious challenge for mould and machine technology as well as for process control. Polymer lenses were manufactured with a modularly designed injection-compression mould base, thus different injection-compression moulding technologies could be examined. To evaluate the quality of optical parts the accuracy of the moulded geometry as well as the resulting optical performance has been analysed. At present a geometrical moulding accuracy in the lower micron range has been achieved. Overall injection-compression moulded lenses showed a better optical performance than injection moulded lenses.

UTILIZING ADVANCED SIMULATION AND MELT MANAGEMENT TECHNOLOGIES TO RE-DEFINE THE INDUSTRY STANDARD

Eric D. Bowersox, May 2010

Plastic products are occasionally designed in such a way that due to required injection locations and polymer flow traits the product will inherit certain quality defects. Two specific defects that if generated could often constitute a non-conforming product are weak weld lines and burn marks. Initial process alterations can be utilized in order to minimize or eliminate defects; however more costly mold or product alterations are often necessary. This paper presents a case study of how plastic flow simulation and the latest in melt management technologies can be utilized in order to create products that re-define the industries approach to handling these specific product defects.

UTILIZING ADVANCED SIMULATION AND MELT MANAGEMENT TECHNOLOGIES TO RE-DEFINE THE INDUSTRY STANDARD

Eric D. Bowersox, May 2010

Plastic products are occasionally designed in such a way that, due to required injection locations and polymer flow traits, the product will inherit certain quality defects. Two specific defects that if generated could often constitute a non-conforming product are weak weld lines and burn marks. Initial process alterations can be utilized in order to minimize or eliminate defects; however more costly mold or product alterations are often necessary. This paper presents a case study of how plastic flow simulation and the latest in melt management technologies can be utilized in order to create products that re-define the industries approach to handling these specific product defects.

A METHOD TO OBTAIN BALANCED FLOW IN PROFILE EXTRUSION DIES

Oktay Yilmaz , KadirKirkkopru, May 2010

One of the problems encountered in the extrusion of complex profiles is the unbalanced flow of polymer melt as it leaves the die. In this study a systematic method to obtain balanced flow is proposed by using a CFD tool. First the results of a production test that is performed for a profile and the results of the CFD simulation compared and it is seen that the velocity distribution at the die exit is similar indicating an unbalanced flow. For the profile to be produced a new die geometry which provides balanced flow at the die exit is proposed by use of numerical simulations. A balanced exit flow is achieved by using flow separators.

A METHOD TO OBTAIN BALANCED FLOW IN PROFILE EXTRUSION DIES

Oktay Yilmaz , KadirKirkkopru, May 2010

One of the problems encountered in the extrusion of complex profiles is the unbalanced flow of polymer melt as it leaves the die. In this study, a systematic method to obtain balanced flow is proposed by using a CFD tool. First, the results of a production test that is performed for a profile and the results of the CFD simulation compared and it is seen that the velocity distribution at the die exit is similar, indicating an unbalanced flow. For the profile to be produced, a new die geometry which provides balanced flow at the die exit is proposed by use of numerical simulations. A balanced exit flow is achieved by using flow separators.