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.
The SPE Library is just one of the great benefits of being an SPE member! Are you taking advantage of all of your SPE Benefits?
Conference Proceedings
GRADIENT MULTILAYER FILMS BY FORCED ASSEMBLY COEXTRUSION
M. Ponting , A. Hiltner , E. Baer, May 2010
A breakthrough in the design of novel uneven" split layer multiplying dies has enabled co-extrusion processing advancements from uniform to gradient layer thickness multilayered films. "Uneven" split layer multiplier and "forced assembly" technology provides flexibility in the design of gradient multilayer film distributions by (1) altering the die A/B split ratio and (2) changing the sequencing of a series of "uneven" split layer multiplying dies. Flexibility in the design of gradient layer distributions allows for the development of unique multilayered films for a variety of applications. Gradient films with layer thickness distributions in the micro- and nanometer scale have been shown to possess wide optical reflection bands which are envisioned to be used as light enhancers filters and reflectors in electronic and information devices. A breakthrough in the design of novel uneven" split layer multiplying dies has enabled co-extrusion processing advancements from uniform to gradient layer thickness multilayered films. "Uneven" split layer multiplier and "forced assembly" technology provides flexibility in the design of gradient multilayer film distributions by (1) altering the die A/B split ratio and (2) changing the sequencing of a series of "uneven" split layer multiplying dies. Flexibility in the design of gradient layer distributions allows for the development of unique multilayered films for a variety of applications. Gradient films with layer thickness distributions in the micro- and nanometer scale have been shown to possess wide optical reflection bands which are envisioned to be used as light enhancers filters and reflectors in electronic and information devices and controlled release applications. "
PROPOSAL OF WET REGULATED INSULATION MOLD SYSTEM (WRI-MOLD) FOR HIGH-GRADE SURFACE QUALITY UNDER LOW INJECTION PRESSURE
Chia-Hsun Chen, Kun Chang Lin, Chen-Feng Kuan, Hsu-Chiang Kuan, May 2010
In most injection molded parts, the surface appearance is especially important to enhance aesthetic qualities. Surface irregularities such as sink marks, weld lines and flow marks are undesirable although often unavoidable. Therefore, a novel concept, known as WRI-molding, was introduced whereby the temperature of the mold cavity and core surfaces were carefully regulated in order to change the tackiness of the resin as well as to generate resin movement towards the cavity surface to compensate for any surface irregularities of the product. Another interesting aspect of this technique is the possibility of producing moldings with good surface appearance under low injection pressures, irrespective of whether the material involved is of a neat resin or a filled composite system. The effectiveness of the WRI-molding technique in surface replication and enhancement of surface gloss in moldings will be discussed.
PROPERTIES OF COMPOSITES PREPARED FROM COCKLESHELL-DERIVED CaCO3 FILLED POLYPROPYLENE
Abbass Mokhtarzadeh, Avraham Benatar, Chung-Yuan Wu, May 2010
Mineral fillers were prepared from cockleshell derived CaCO3 and used to fill polypropylene. The composites were prepared by melt blending and fabricated by injection and compression molding techniques. The effects of micro filler on crystal structure, crystallization and thermal degradation characteristics of filled polypropylene composites were elucidated. The cockleshell filler promoted the formation of the ?ý- crystalline phase in PP, which improved the rigidity and toughness of the composites. However, stearic acid treatments on the filler would significantly affect the nucleation process and therefore hindered crystallization. Acceleration in thermal degradation of PP was also noted with increasing filler loading.
EFFICACY OF SATURATED DESIGN OF EXPERIMENTS IN MULTIVARIATE PROCESS CHARACTERIZATION
Darin VanDerwalker , Stephen Johnston , Dan Hazen , David Kazmer, May 2010
Process characterization provides a model of process responses as a function of process factors, which is useful for process optimization and quality control. In this paper, four Design of Experiments (DOE) are implemented for a thin wall molding process, including two fractional factorial designs, a D-optimal design, and a supersaturated fractional factorial design. The capability of the DOEs are subsequently analyzed with respect to the estimated main effects and defect prediction capabilities. The results indicate that fully saturated designs are satisfactory for process characterization, but all critical process factors should be investigated. Experimental designs having confounded process factors were found preferable to experimental designs of similar size that were not confounded, but investigated fewer factors.
DEPENDANCE OF CRACK-TIP TEMPERATURE ON STRESS INTENSITY AND NOTCH-SENSITIVITY OF POLYETHYLENE TEREPHTHALATE
Hyogap Kim, Ho-Jong Kang, May 2010
During tensile loading, the temperature of notched materials is correlated to the applied stress and its resultant strain. At crack propagation, the strain energy that is released, or work done during deformation, affects the temperature at the crack tip and the yielding axis. The intensity of the temperature is seen to depend on the notch depth and stress intensity at the notch root. In this investigation, an infrared camera was used to monitor the temperature distribution around the crack axis during the tensile loading of notched PET specimens. The correlations between the temperature distributions at the crack-tip, notch sensitivity and essential work of fracture were established. Results reveal that the one of the major fracture mechanism that increases temperature is a mixed mode fracture. This occurs when crazing precedes semiductile/ brittle fracture. It was observed that the highest change at the notch root temperature occurred in samples where the notch depths are located at the interface between the skin and the core regions.
TEXTILE INSERTED SANDWICH STRUCTURE BY INJECTION-PRESS MOLDING
Mark D. Wetzel, May 2010
The current study is to research the sandwich molding process of both the plate type reinforced material inserted sandwich structure and the textile inserted sandwich structure. The sandwich molding process in this study consists of injection molding process and injection-press molding process. The sandwich plate type insert glass fiber-reinforced polypropylene (GFPP) instead of textile was studied mainly. Additionally, the relationship between the improvement of strength and the lightening of weight was investigated through controlling the position of the plate type insert of GFPP in the sandwich structure. It is found that this sandwich molding process was effective in controlling position of the insert in the sandwich structure. And through controlling position of the insert, this sandwich process was possible to improve the strength and to lighten the weight by reducing thickness of the sandwich structure.
ENVIRONMENTAL HEALTH AND SAFETY ISSUES AND APPROACHES FOR THE PROCESSING OF POLYMER NANOCOMPOSITES
Mark D. Wetzel, May 2010
In 2005 Environmental Defense and DuPont entered into a partnership to develop a framework that seeks to identify and address potential environmental health and safety (EH&S) risks of nano-scale materials. The Nano Risk Framework was published to establish a systematic and disciplined process to identify and reduce potential risks during nanomaterial development and meet continued product stewardship commitments [1]. This paper describes an approach developed for and the application of the Framework to the processing of polymer nanocomposites at laboratory and semi-works scales. Carbon nanotubes were melt-blended into a polymer matrix with a batch mixer to improve mechanical and electrical properties.Nano-TiO2 nanocomposites were made on laboratoryand semi-works extruders. These case studies exemplify DuPontƒ??s approach to handling nanomaterials in the product research and evaluation phase of development.Utilization of the Framework enabled further refinement of internal EH&S management procedures and to identify questions to be answered for such applications before they move to commercialization.
NOVEL SILOXANE BASED CORE-SHELL IMPACT MODIFIERS
Remon Pop-Iliev, Kyoung-Ho Lee, Yean Cheang Chew, Chul B. Park, May 2010
Core-shell impact modifiers are special class of elastomers, which can be tailored to possess special functional groups and wide range of desired particle sizes. Such structural modifications can result in achieving miscibility or compatibility enabling desired/enhanced properties in polymeric compositions. A core-shell impact modifier based on siloxane core and polystyrene shell, with tunable particle size was synthesized by emulsion polymerization. The performance of synthesized material was evaluated in polyphenylene ether (PPE) formulations and compared with that of styrene block copolymers.
PROCESSING FINE-CELLED RECYCLABLE CBA-BASED POLYOLEFIN FOAMS IN COMPRESSION FOAM MOLDING
Remon Pop-Iliev , Kyoung-Ho Lee , Yean Cheang Chew , Chul B. Park, May 2010
This paper focuses on understanding the technological potentials for producing recyclable polyolefin foams by using a modified technique of the conventional compression molding process, referred to as compression foam molding. A two-step compression foam molding method is being developed. The main processing feature of this method is that it allows for complete sintering of the non-foamable resin prior the activation of the CBA. First, completely sintered intermediate foamable products that have no pre-decomposed CBA particles and entrapped air bubbles are manufactured. Second, these intermediate products are used in the actual foaming process. The principal advantage of this compression foam molding method is that it produces high quality recyclable foamed structures with high volume expansion ratios by avoiding the need for cross linking.
TRUE 3D NUMERICAL SIMULATION IN INJECTION COMPRESSION MOLDING (ICM)
H. Inoya, W. Klinklai, Y. W. Leong, H. Hamada, May 2010
Generally, injection compression molding (ICM) can provide better product quality than that of conventional injection molding (CIM) in some injection processes and products, such as micro-injection molding, less residual stress parts, and so on. To get a better understanding of ICM, a 3D simulation technology based on finite volume method is proposed. In this study, the influence of various process parameters with ICM is performed by using light guide plate (LGP) models. The cavity pressure distribution with ICM is lower and more uniform than that with CIM which will have more opportunities result in lower volume shrinkage and get better product quality.
MECHANICAL PROPERTIES OF RECYCLED PET/PP INJECTION MOLDINGS
H. Inoya , W. Klinklai , Y. W. Leong , H. Hamada, May 2010
Compatibilization effects on the phase morphology and mechanical properties of post-consumer recycled poly(ethylene terephathalate) (RPET)/ polypropylene (PP) blends were investigated. The blending of RPET and PP (RPET/PP:95/5) was carried out by a singlescrew extrusion process in the presence of various amounts of compatibilizer ranging from 0-35 phr based on the PP content. The compounded materials were injection molded into dumbbell test pieces which were subsequently used for mechanical and morphological characterizations. The addition of compatibilizer of up to 15 phr resulted in a size reduction of the dispersed phase while an apparent increase in density of the blends suggests an improvement in interfacial interaction following the depletion of hollow ligaments between the PP and RPET phases. The changes in morphological structure significantly affect the tensile and impact resistance of the moldings. An elongation at break (EB) of more than 350% could be achieved with the incorporation of just 15 phr of compatibilizer (as compared to <90% EB for un-compatibilized specimens) while significantly better impact performance was observed in all compatibilized specimens.
MICRO-FEATURE REPLICATION OF CYCLIC OLEFIN COPOLYMER AT ELEVATED MOLD TEMPERATURE
Peiman Mosaddegh , David C. Angstadt, May 2010
The focus of this study is on the ability of Cyclic Olefin Copolymer (COC) to replicate micron and sub-micron features when molded at an elevated mold temperature without externally applied pressure. Molding was performed on a treated silicon mold containing surface features as small as 700nm in depth with aspect ratios ranging from 5 to 0.02. In this study temperature was selected in order to overcome the viscosity resistance of polymer based on contact angle (wettability) measurements. Since increasing mold temperature can cause sticking to the mold surface an anti-adhesive layer made by TCS has deposited on the surface to facilitate mold release. Feature replication was assessed using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) to compare the molded feature depth ratio and surface roughness. It was observed that for the features with an aspect ratio (depth/width) bigger than 0.8 the quality of the feature replication declines. Without the anti-adhesive layer COC has shown rough surface finish especially in low aspect ratio features because of sticking to the silicon oxide layer. Using anti-adhesive improved surface finish of molded part and reduced the defects such as flashing and tear-off during demolding.
MICRO-FEATURE REPLICATION OF CYCLIC OLEFIN COPOLYMER AT ELEVATED MOLD TEMPERATURE
Peiman Mosaddegh , David C. Angstadt, May 2010
The focus of this study is on the ability of Cyclic Olefin Copolymer (COC) to replicate micron and sub-micron features when molded at an elevated mold temperature without externally applied pressure. Molding was performed on a treated silicon mold containing surface features as small as 700nm in depth with aspect ratios ranging from 5 to 0.02. In this study, temperature was selected in order to overcome the viscosity resistance of polymer based on contact angle (wettability) measurements. Since increasing mold temperature can cause sticking to the mold surface, an anti-adhesive layer made by TCS has deposited on the surface to facilitate mold release. Feature replication was assessed using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) to compare the molded feature depth ratio and surface roughness. It was observed that for the features with an aspect ratio (depth/width) bigger than 0.8 the quality of the feature replication declines. Without the anti-adhesive layer, COC has shown rough surface finish especially in low aspect ratio features because of sticking to the silicon oxide layer. Using anti-adhesive improved surface finish of molded part and reduced the defects such as flashing and tear-off during demolding.
NANOLAYERING AS AN ENABLING TECHNOLOGY FOR STUDYING FRACTIONATED CRYSTALLIZATION OF POLYPROPYLENE
D.S. Langhe , A. Hiltner , E. Baer, May 2010
Layer-multiplying coextrusion was used to fabricate assemblies of 257 layers in which PP nanolayers alternated with thicker polystyrene (PS) layers. When the assembly was heated into the melt interfacial driven breakup of the 12 nm PP layers produced a dispersion of submicron PP particles in a PS matrix. In the absence of a nucleating agent the submicron particles obtained from breakup of 12 nm PP layers crystallize almost exclusively by homogeneous nucleation at about 40 ºC. Addition of a nucleating agent to the PP layers offers a unique opportunity to study the nature of heterogeneous nucleation.
NANOLAYERING AS AN ENABLING TECHNOLOGY FOR STUDYING FRACTIONATED CRYSTALLIZATION OF POLYPROPYLENE
D.S. Langhe , A. Hiltner , E. Baer, May 2010
Layer-multiplying coextrusion was used to fabricate assemblies of 257 layers, in which PP nanolayers alternated with thicker polystyrene (PS) layers. When the assembly was heated into the melt, interfacial driven breakup of the 12 nm PP layers produced a dispersion of submicron PP particles in a PS matrix. In the absence of a nucleating agent, the submicron particles obtained from breakup of 12 nm PP layers crystallize almost exclusively by homogeneous nucleation at about 40 ?§C. Addition of a nucleating agent to the PP layers offers a unique opportunity to study the nature of heterogeneous nucleation.
THREE-DIMENSIONAL MODELING OF GAS PENETRATIONS DURING GAS-ASSISTED INJECTION MOLDING
Reiichi Konishi, Kazushi Yamada, Yasuo Hashimoto, Yew Wei Leong, Tetsuya Tsujii, Hiroyuki Hamada, May 2010
Although Gas-Assisted Injection Molding (GAIM) has gained acceptance in eliminating sink marks and preventing warpage in the plastic industry, many problems are still encountered for the complicated gas-melt flow interactions. In this study, a full 3D numerical approach is proposed to model GAIM process. The behavior of gas penetration are investigated numerically. Simulation results are in the form of fully featured 3-D animations, giving highly realistic images of flow fields. The predicted melt front location and gas penetration behavior show good agreement with the experimental results, and several complex applications are shown as well.
MECHANICAL PROPERTIES OF HEAT-SEALED PART IN THERMAL LAMINATED FILM
Reiichi Konishi , Kazushi Yamada , Yasuo Hashimoto , Yew Wei Leong , Tetsuya Tsujii , Hiroyuki Hamada, May 2010
Plastic packaging has been a very important application that significantly improved our way of living. One of the most common forms of plastic packaging is the plastic bag which is often heat sealed at several ends. In order to increase the heat-seal performance of plastic bags laminated films e.g. oriented PP/cast PP have been used.However much solvent is used during the laminating process and the effects of volatile compounds on health and environment were the main concerns when introducing these solvents. Hence in this study a new lamination process i.e. thermal lamination was developed to avoid the usage of solvents. The characteristics of the thermal laminated films as well as their mechanical properties upon heat-sealing are discussed.
MECHANICAL PROPERTIES OF HEAT-SEALED PART IN THERMAL LAMINATED FILM
Reiichi Konishi , Kazushi Yamada , Yasuo Hashimoto , Yew Wei Leong , Tetsuya Tsujii , Hiroyuki Hamada, May 2010
Plastic packaging has been a very important application that significantly improved our way of living. One of the most common forms of plastic packaging is the plastic bag, which is often heat sealed at several ends. In order to increase the heat-seal performance of plastic bags, laminated films e.g. oriented PP/cast PP have been used. However, much solvent is used during the laminating process and the effects of volatile compounds on health and environment were the main concerns when introducing these solvents. Hence, in this study, a new lamination process, i.e. thermal lamination, was developed to avoid the usage of solvents. The characteristics of the thermal laminated films as well as their mechanical properties upon heat-sealing are discussed.
MECHANICAL PROPERTIES OF INJECTION-MOLDED JUTE/GLASS REINFORCED HYBRID COMPOSITES
Tomoko Ohta , Yoshihiro Takai , Yew Wei Leong , Asami Nakai , Hiroyuki Hamada , Tsutomu Nagaoka, May 2010
Bio-composites are generally made from natural fibers as reinforcement and a biodegradable polymer matrix such as poly(lactic acid) or poly(caprolactone).However the mechanical properties of these composites are relatively low. For practical applications glass fibers were added to create hybrid composites. The concept of ƒ??degree of greenƒ? is introduced to identify the true content of biodegradable material in the composite. Three different fiber hybridization methods are proposed i.e.dry blending mixing of pellets and sandwich injection molding. The mechanical properties of these hybrid composites are evaluated and the relation between the properties and degree of green is discussed.
DEVELOPMENT OF MOISTURE RESISTANT RECYCLED POLY(ETHYLENE TEREPHTHALATE)
Y. W. Leong , H. Inoya , S.F. Aminuddin , B.C. Ogazi-Onyemaechi , H. Hamada, May 2010
The recycling activities related to poly(ethylene terephthalate) PET has been slow since the material is always thought to possess inferior properties when compared to virgin PET. This study involves the development of novel processing methods to significantly enhance the properties of recycled PET (RPET) especially in terms of moisture resistance.This is particularly important especially when RPET is used for further processing that involves heating such as injection molding since the presence of moisture would severely degrade the material. The drying process of RPET pellets would also require at least a few hours which could significantly affect production cycles. The improvement in moisture resistance can be realized through the control of crystallinity and morphological structure of the RPET pellets during compounding and extrusion processes.
.jpg)
.jpg)
.jpg)
.jpg)
