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
THE DEPENDENCE OF WALL THICKNESS ON CHANGES IN MATERIAL AND PROCESS CONDITIONS IN PLUG ASSIST THERMOFORMING
Christina Sabine Härter , Hans-Gerhard Fritz , Noel Tessier , Karel Kouba, May 2008
The European Commission, 6th Framework Program, Cooperative Research Project ƒ? Plug Materials Influence on Final Part Quality in the Thermoforming Processƒ? with Project acronym ƒ??PlugInƒ has as its goal to improve the understanding of plug assist thermoforming to increase productivity and competitiveness of the European thermoforming industry. This paper presents the PlugIn project work investigating the dependence of part wall thickness due to changes in plug-sheet material combination, plug geometry, plug velocity, plug depth and forming temperature.
ASSESSING THE THERMOFORMABILITY OF HIGH-PERFORMANCE POLYMERS FOR USE IN MEDICAL PACKAGING APPLICATIONS
T.P. O’Brien , G.M. McNally , W.R. Murphy , B.G. Millar , G.S. Garrett , A.H. Clarke, May 2008
A considerable number of polymers are available for usein medical and pharmaceutical packaging applications.Polymers such as polypropylene glycol modifiedpoly(ethylene terephthalate) polyacrylonitrile cyclicolefin copolymer and polychlorotrifluoroethylene exhibitdifferent mechanical and thermal properties therebyrequiring different processing conditions. Thethermoformability of these different polymers can beassessed in order to establish relative performance metricsprior to full scale production trials. This paper presentsmethods and analyses for assessing thermoformability.
THE ROLE OF GRAFTING DEGREE IN THE DISPERSION OF SILICA/POLYACRYLATE NANOCOMPOSITE PARTICLES INTO POLYACRYLATE MATRIX
He-ming Lin , Zhi-Qi Cai , Yan Yuan , Lin Lei , Dong-ming Qi, May 2008
A series of ‘guava-like’ silica/polyacrylate nanocomposite particles with different grafting degrees were prepared via mini-emulsion polymerization. The silica/polyacrylate composite particles were melt-mixed with unfilled polyacrylate resin to prepare the corresponding silica/polyacrylate molded composites and the dispersion mechanism of these silica particles from the ‘guava-like’ composite particles into polyacrylate matrix was studied by the section transmission electron microscope (TEM) micrographs of silica/polyacrylate molded composites. It was found that the grafting degree of silica particles played a crucial role in the dispersion of silica/polyacrylate composite particles into the polyacrylate matrix.
THE ROLE OF GRAFTING DEGREE IN THE DISPERSION OF GUAVA-LIKE SLICE/POLYACRYLATE MATRIX
He-ming Lin , Zhi-Qi Cai , Yan Yuan , Lin Lei , Dong-ming Qi, May 2008
A series of guava-like silica/polyacrylate nanocomposite particles with different grafting degrees were prepared via mini-emulsion polymerization. The silica/polyacrylate composite particles were melt-mixed with unfilled polyacrylate resin to prepare the corresponding silica/polyacrylate molded composites, and the dispersion mechanism of these silica particles from the ƒ??guava-likeƒ?? composite particles into polyacrylate matrix was studied by the section transmission electron microscope (TEM) micrographs of silica/polyacrylate molded composites. It was found that the grafting degree of silica particles played a crucial role in the dispersion of silica/polyacrylate composite particles into the polyacrylate matrix.
NEW PERSPECTIVE ON HEAT DEFLECTION TEMPERATURE OF GLASSY POLYCARBONATE
Xiangyang Li , James Mason, May 2008
For polycarbonate the HDT values can vary over 20±C. Many factors a®ect the test results. Among these ther- mal dilatation and creep were discussed in detail. Quan- titatively the contribution from thermal dilatation to HDT values varies little with physical aging time but the contribution from creep to HDT values changes greatly. When creep is insigni¯cant the HDT values can be cal- culated from an elastic beam de°ection equation and are close to the Tg values. This paper qualitatively disputes the claims of the e®ect of residual stress on HDT values. It is argued that changes in residual stress level and HDT values with physical aging are symptoms of the structural relaxation but no causal e®ect exists between these two symptoms. As a test method for amorphous polymers Vicat or Tg can provide more reliable results than HDT.
NEW PERSPECTIVE ON HEAT DEFLECTION TEMPERATURE OF GLASSY POLYCARBONATE
Xiangyang Li, May 2008
For polycarbonate, the HDT values can vary over 20?øC. Many factors affect the test results. Among these, thermal dilatation and creep were discussed in detail. Quantitatively, the contribution from thermal dilatation to HDT values varies little with physical aging time, but the contribution from creep to HDT values changes greatly. When creep is insignificant, the HDT values can be calculated from an elastic beam deflection equation and are close to the Tg values. This paper qualitatively disputes the claims of the effect of residual stress on HDT values. It is argued that changes in residual stress level and HDT values with physical aging are symptoms of the structural relaxation, but no causal effect exists between these two symptoms. As a test method for amorphous polymers, Vicat or Tg can provide more reliable results than HDT.
POLYMER-POLYMER INTERFACIAL SLIP MEASUREMENTS IN MULTILAYERED FILM
Patrick C. Lee , Hee Eon Park , Christopher W. Macosko , John M. Dealy, May 2008
Significant slip can occur during flow of twoimmiscible polymers due to reduced entanglements at theirinterface. The slip is of practical importance because of itseffect on morphology and adhesion of these multi-phasematerials such as disordered two-phase blends andmultilayer films. Using rheological technique we studiedthe interfacial slip in co-extruded multilayer films. Theviscosity drop of a multilayer sample below the averageviscosity of two neat components was observed for bothpolypropylene/polystyrene and polyethylene/fluoropolymer systems indicating interfacial slip.Furthermore the viscosity drop of a multilayer sampleincreased with the number of layers.
POLYMER-POLYMER INTERFACIAL SLIP MEASUREMENTS IN MULTILAYERED FILM
Patrick C. Lee , Hee Eon Park , Christopher W. Macosko , John M. Dealy, May 2008
Significant slip can occur during flow of two immiscible polymers due to reduced entanglements at their interface. The slip is of practical importance because of its effect on morphology and adhesion of these multi-phase materials, such as disordered two-phase blends and multilayer films. Using rheological technique, we studied the interfacial slip in co-extruded multilayer films. The viscosity drop of a multilayer sample below the average viscosity of two neat components was observed for both polypropylene/polystyrene and polyethylene /fluoropolymer systems, indicating interfacial slip. Furthermore, the viscosity drop of a multilayer sample increased with the number of layers.
STUDY OF TAKE-UP VELOCITY IN ENHANCING TENSILE PROPERTIES OF ALIGNED ELECTROSPUN NYLON 6 FIBERS
John Najem , Shing-Chung Wong, May 2008
The variation of both the tensile properties and the thermal properties of aligned electrospun fibers with the take-up velocity (TUV) of disc collector have not been widely investigated due to the difficulty of handling aligned nanofibers and measuring low loads. In this paper 25% of nylon 6 solution was electrospun into fibers and the fibers were aligned using a rotating disc collector. We evaluated both the mechanical and the thermal properties of aligned electrospun nylon 6 nanofibers having a diameter less than 200 nm as a function of the TUV based on a disc collector. It was determined that by increasing the TUV from 14.2 m/s to 21.4 m/s the tensile properties showed a substantial increase including the elastic modulus the strain energy density and the tensile strength which increased by 108% 100% and 75% respectively. Meanwhile the melting temperature remained the same compared to the bulk material.
STUDY OF TAKE-UP VELOCITY IN ENHANCING TENSILE PROPERTIES OF ALIGNED ELECTROSPUN NYLON 6 FIBERS
John Najem , Shing-Chung Wong, May 2008
The variation of both the tensile properties and the thermal properties of aligned electrospun fibers with the take-up velocity (TUV) of disc collector have not been widely investigated due to the difficulty of handling aligned nanofibers and measuring low loads. In this paper, 25% of nylon 6 solution was electrospun into fibers and the fibers were aligned using a rotating disc collector. We evaluated both the mechanical and the thermal properties of aligned electrospun nylon 6 nanofibers, having a diameter less than 200 nm, as a function of the TUV based on a disc collector. It was determined that by increasing the TUV from 14.2 m/s to 21.4 m/s, the tensile properties showed a substantial increase including the elastic modulus, the strain energy density, and the tensile strength which increased by 108%, 100%, and 75%, respectively. Meanwhile, the melting temperature remained the same compared to the bulk material.
MICROFLUIDIC MIXER FOR POLYMER MELTS
Doyoung Moon , Kalman B. Migler, May 2008
We present a novel microfluidic mixer for high temperature polymer melts based on the platform of the Multi-sample Micro-slit Rheometer (MMR). The device is essentially a static mixer with eight consecutive units of splitting and recombination flow formed by stacking three stainless steel shims (50 ?m thickness). The mixing results show both multilayer and domain/matrix morphologies depending on the channel configuration and blend pair. This mixer will be particularly useful not only as a polymer melt mixer but as a multilayer processor when a limited material quantity (typical sample size ? 20 ?L) is available.
MICROFLUIDIC MIXER FOR POLYMER MELTS
Doyoung Moon , Kalman B. Migler, May 2008
We present a novel microfluidic mixer for high temperature polymer melts based on the platform of the Multi-sample Micro-slit Rheometer (MMR). The device is essentially a static mixer with eight consecutive units of splitting and recombination flow formed by stacking three stainless steel shims (50 ?¬m thickness). The mixing results show both multilayer and domain/matrix morphologies depending on the channel configuration and blend pair. This mixer will be particularly useful not only as a polymer melt mixer but as a multilayer processor when a limited material quantity (typical sample size ƒ?? 20 ?¬L) is available.h
3D SIMULATIONS OF A REACTIVE FLOW IN SCREW ELEMENTS OF CLOSELYINTERMESHING TWIN SCREW EXTRUDERS: A SCALE-UP ANALYSIS
Estanislao Ortiz-Rodriguez , Costas Tzoganakis, May 2008
The peroxide-initiated degradation of polypropylene in fully-filled screw elements of closely intermeshing twinscrew extruders is being analyzed. For this purpose threedimensional simulations are being implemented to describe this reactive flow in screw elements of two different size extruders. The effects of the initial peroxide concentration mass throughput and especially extruder size on the final weight-average molecular weight and poly-dispersity index of the product are studied. In relation to the later the temperature of reaction resulting from the specified processing conditions is discussed.
DESIGN AND EVALUATION OF AN INTERBODY FUSION CAGE MOLD
V. Picón , M. Matos , C. Müller-Karger , M. V. Candal , H. Nicola, May 2008
The main goal of this project was to design evaluate and validate an interbody fusion cage (IFC) and its injection mold by means of CAE/CAD and finite elements tools (Pro-ENGINEER C-MOLD and ANSYS). IFC is employed as a supplement in the lumbar fusion. PEEK was chosen for IFC manufacture. Based on the interbody cage design two cavities and a double opening ejection system were used in the mold. Molds with different cooling and feeding systems were designed and evaluated using modelator and simulation software (C-MOLD). Results indicate that the best mold has only one standard lateral gate and four cooling channels in each cavity. The cycle time was less than 36 sec. After a financial study this project represents a feasible solution for Venezuelan patients.
ADVANCES IN PLASTICS JOINING TECHNOLOGIES FOR THE ASSEMBLY OF MEDICAL DEVICES
Nitin P. Phadnis, May 2008
With demand for the use of plastics in Medical Devices expected to continue growing there is also a growing demand for improved control and analysis of related assembly processes. Additionally there is a growing demand to use plastics in MEMS and Micro-fluidics for analytical and drug delivery devices. Therefore manufacturers are increasingly looking for joining technologies that are particulate free and will not occlude miniature channels. These trends have led to the introduction of several new methods to control monitor and analyze the assembly process as well as led to the use of new plastics joining technologies such as Laser and Infra Red Welding.
ADVANCES IN PLASTICS JOINING TECHNOLOGIES FOR THE ASSEMBLY OF MEDICAL DEVICES
Nitin P. Phadnis, May 2008
With demand for the use of plastics in Medical Devices expected to continue growing, there is also a growing demand for improved control and analysis of related assembly processes. Additionally there is a growing demand to use plastics in MEMS and Micro-fluidics for analytical and drug delivery devices. Therefore manufacturers are increasingly looking for joining technologies that are particulate free and will not occlude miniature channels. These trends have led to the introduction of several new methods to control, monitor and analyze the assembly process as well as led to the use of new plastics joining technologies such as Laser and Infra Red Welding.
HYPERELASTIC MODELING OF ENHANCED MECHANICAL PROPERTIES OF ELECTROSPUN POLY(?-CAPROLACTONE) FIBERS
Xiaofan Wei , Shing-Chung Wong , Avinash Baji, May 2008
Little is understood on the deformation of electrospun nanofibers. This study aims to evaluate the electrospun nanofiber deformation in both macroscopic and nanometer length scales using the classical hyperelastic models. The Mooney-Rivlin models are used to evaluate the tensile properties of poly(?-caprolactone) (PCL) made by the electrospinning technique. The stress-strain relationships of single fibers are reported. This study also provides comparative analyses among Mooney-Rivlin models. Analytical calculations illustrate the importance of understanding crystallinity and molecular orientations of nanofibers.
HYPERELASTIC MODELING OF ENHANCED MECHANICAL PROPERTIES OF ELECTROSPUN POLY(?æ-CAPROLACTONE) FIBERS
Xiaofan Wei , Shing-Chung Wong , Avinash Baji, May 2008
Little is understood on the deformation of electrospun nanofibers. This study aims to evaluate the electrospun nanofiber deformation in both macroscopic and nanometer length scales using the classical hyperelastic models. The Mooney-Rivlin models are used to evaluate the tensile properties of poly(?æ-caprolactone) (PCL) made by the electrospinning technique. The stress-strain relationships of single fibers are reported. This study also provides comparative analyses among Mooney-Rivlin models.Analytical calculations illustrate the importance of understanding crystallinity and molecular orientations of nanofibers.
THE EFFECT OF UV IRRADIATION ON MELTING AND CRYSTALLIZATION BEHAVIOR OF POLY(1-BUTENE)
Lubomír Bení?ek , Roman ?ermák , Vincent Verney , Sophie Commereuc , Martin Obadal, May 2008
The work directs attention towards the influence of natural weathering and accelerated UV degradation on thermal behavior and subsequent transformation behavior of isotactic poly(1-butene) (PB-1). For these purposes two different commercial-available grades of PB-1 were chosen. Specimens prepared by compression molding were UV irradiated for 0 to 40 hours and naturally weathered up to 63 days. Significant changes were consequently observed in crystallization and melting behavior as well as in the phase transformation mechanism.
THE EFFECT OF UV IRRADIATION ON MELTING AND CRYSTALLIZATION BEHAVIOR OF POLY(1-BUTENE)
Lubomír Bení?ek , Roman ?ermák , Vincent Verney , Sophie Commereuc , Martin Obadal, May 2008
The work directs attention towards the influence of natural weathering and accelerated UV degradation on thermal behavior and subsequent transformation behavior of isotactic poly(1-butene) (PB-1). For these purposes, two different commercial-available grades of PB-1 were chosen. Specimens prepared by compression molding were UV irradiated for 0 to 40 hours and naturally weathered up to 63 days. Significant changes were consequently observed in crystallization and melting behavior as well as in the phase transformation mechanism.
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