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
ADVANCED RESULTS OF A PROSPECTIVE STUDY ON FLEXIBLE PLASTIC PACKAGING IN ANDEAN COUNTRIES: SCENARIOS AND STRATEGIES FOR THE PERIOD 2003 ƒ?? 2013
María del Pilar Noriega , Juan Diego Sierra, May 2008
A prospective study on flexible plastic packaging was carried out in Andean Countries with the participation of two plastic research institutes and 20 companies including raw material manufacturers processors converters and end users.The inputs of this prospective study were a review of the state of the art on flexible packaging a benchmarking study considering the 10 most important companies a study using the Delphi method with national and international experts who identified the key variables to the development and progress of the flexible packaging in the region and workshops.This study generated new projects and products on the field of barrier smart and active packaging biodegradable materials among others; it shows that the Andean region is applying R&D and technological alliances in its industrial processes.
TRITAN™ COPOLYESTERS
Emmett Crawford, May 2008
Tritan™ copolyesters are tough transparent copolyesters recently developed by Eastman Chemical Company. These new copolyesters have higher glass transition temperatures than Eastman’s heritage copolyesters of PETG PCTG and PCTA. The properties of Tritan™ copolyesters allow it to be used in applications in a variety of markets from housewares to signs. The unique properties of Tritan™ copolyesters are achieved by modifying poly(1 4-cyclohexylenedimethylene terephthalate) or PCT with 2 2 4 4-tetramethyl-1 3- cyclobutanediol (TMCD) . The properties of Tritan™ copolyesters can be tuned to meet the demands of applications by changing the level of TMCD modification. This paper describes the basic chemistry and structureproperty relationships of Tritan™ copolyesters. In addition this paper describes the properties for some of the commercial Tritan™ copolyesters grades available.
TRITAN COPOLYESTERS
Emmett Crawford, May 2008
Tritan copolyesters are tough, transparent copolyesters recently developed by Eastman Chemical Company. These new copolyesters have higher glass transition temperatures than Eastmanƒ??s heritage copolyesters of PETG, PCTG, and PCTA. The properties of Tritanƒ?› copolyesters allow it to be used in applications in a variety of markets from housewares to signs. The unique properties of Tritanƒ?› copolyesters are achieved by modifying poly(1,4-cyclohexylenedimethylene terephthalate), or PCT, with 2,2,4,4-tetramethyl-1,3- cyclobutanediol (TMCD) . The properties of Tritanƒ?› copolyesters can be tuned to meet the demands of applications by changing the level of TMCD modification.This paper describes the basic chemistry and structure-property relationships of Tritanƒ?› copolyesters. In addition, this paper describes the properties for some of the commercial Tritanƒ?› copolyesters grades available.
EVALUATION OF MOLECULAR ORIENTATION OF WELDLINE BY POLARIZED LASER-RAMAN SPECTROSCOPY
Koji Yamada , Kiyotaka Tomari, May 2008
Molecular orientation in weldline region of injection molded polypropylene was investigated by polarized laser-Raman spectroscopy. The intensity ratio of two intrinsic peaks in a Raman spectrum of weldline was considered to be a molecular orientation index. By setting the angle of incident laser beam in two ways so as to be parallel and perpendicular to the weldline the molecular orientation around the weldline was able to be clarified in detail. It was found that the molecules in weldline region oriented along the interface of the weldline even inside the moldings. Moreover the orientation degree of the area 0.3 mm away from the interface was higher than that of the interface itself. These findings are much different from our expectation obtained from the former experiments using polystyrene moldings in a similar method which suggests that the orientation parallel to the weldline is limited to the area beneath the surface. Although the cause of this difference has yet to be identified there is little doubt that crystallinity of polypropylene deeply plays an important role on it.
EVALUATION OF MOLECULAR ORIENTATION OF WELDLINE BY POLARIZED LASER-RAMAN SPECTROSCOPY
Koji Yamada , Kiyotaka Tomari , Hiroyuki Hamada, May 2008
Molecular orientation in weldline region of injection molded polypropylene was investigated by polarized laser-Raman spectroscopy. The intensity ratio of two intrinsic peaks in a Raman spectrum of weldline was considered to be a molecular orientation index. By setting the angle of incident laser beam in two ways so as to be parallel and perpendicular to the weldline, the molecular orientation around the weldline was able to be clarified in detail. It was found that the molecules in weldline region oriented along the interface of the weldline even inside the moldings. Moreover, the orientation degree of the area 0.3 mm away from the interface was higher than that of the interface itself. These findings are much different from our expectation obtained from the former experiments using polystyrene moldings in a similar method which suggests that the orientation parallel to the weldline is limited to the area beneath the surface. Although the cause of this difference has yet to be identified, there is little doubt that crystallinity of polypropylene deeply plays an important role on it.
INVESTIGATION OF EVOH/KAOLINITE NANOCOMPOSITE FILMS
Danielle Froio , Sarah Schirmer , Jo Ann Ratto , Matthew Bernasconi , Christopher Thellen , Scott Winroth, May 2008
Two grades of ethylene vinyl alcohol copolymer (EVOH) were compounded with kaolinite nanoparticles at a loading level of 5% and subsequently extruded into blown and cast monolayer films. Films were analyzed for oxygen and water vapor barrier mechanical performance and thermal properties. The films showed slight changes in thermal stability no significant improvement in barrier properties a decrease in Young's modulus and no change in thermal properties such as melt and glass transition temperature.
INFLUENCE OF MOISTURE ON THE MECHANICAL AND BARRIER PROPERTIES OF MULTILAYER AROMATIC POLYAMIDE NANOCOMPOSITE FILMS
Christopher Thellen , Jo Ann Ratto, May 2008
Multilayer nanocomposite films containing nylon MXD6 as a barrier layer were produced through coextrusion and stored at elevated temperatures for various periods of time. Dramatic changes in the mechanical properties and moisture content of these films were observed after storage for 3 days at 140°F. Glasstransition temperature increases of 20-40°C were observed in the films after storage and mechanical testing revealed a shift from ductile to brittle failure as storage time and nanocomposite layer thickness increased.
INFLUENCE OF MOISTURE ON THE MECHANICAL AND BARRIER PROPERTIES OF MULTILAYER AROMATIC POLYAMIDE NANOCOMPOSITE FILMS
Christopher Thellen , Jo Ann Ratto, May 2008
Multilayer nanocomposite films containing nylon MXD6 as a barrier layer were produced through coextrusion and stored at elevated temperatures for various periods of time. Dramatic changes in the mechanical properties and moisture content of these films were observed after storage for 3 days at 140?øF. Glasstransition temperature increases of 20-40?øC were observed in the films after storage, and mechanical testing revealed a shift from ductile to brittle failure as storage time and nanocomposite layer thickness increased.
THE RELATIONSHIP BETWEEN PROCESSING-THERMOMECHANICAL ENVIRONMENT AND STRUCTURE ON INJECTED FLAT PARTS
S.L. Villarroel , R.A. Morales , A. Gordillo , M. Sánchez-Soto, May 2008
The microstructure of an injection moulding polypropylene part has been varied through systematic changes on the process conditions. The specimens were mouldedmodifying the holding pressure mass caudaland gate design. The skin-core structure was characterized by polarized light microscopy. The thermo mechanical environment imposed during processing was characterized using simulation commercial software.From the mould filling stage two thermo mechanical indices were calculated. The results show the relationship between these indexes and the micro structural features obtained in the moulded specimens
TOWARDS QUALITY PRODUCTS FROM BIO-BASED PLASTICS
Rolf Koster, May 2008
The importance of three inter-dependent factors i.e. (1) materials (2) manufacturing and (3) design and engineering is generally recognized. All factors are indispensable and equally important for product development. Manufacturing is often the least structured factor and many designers and materials experts do not consider themselves capable to deal with it. Fortunately expertise is sufficiently available and the best professionals are able to utilize plastics expertise properly in collaborative product development. For bio-based plastics which are rapidly emerging in some specific markets it is already clear that the relation between the three factors is different and more varied than for the currently well-known plastics. Critical factors for increased successful application of bio-based plastics will be product manufacturing and the expectations of applicators and consumers. From interviewing a variety of professionals it was found that clear true and complete information is currently not accessible for most whereas some assumptions are not realistic or not correct particularly the ones related to degradability and to environmental effects. Better and well-structured information will be needed resulting in fulfillment of elementary consumer expectations.
EXPERIMENTAL VERIFICATIONS OF CAE PREDICTIONSONBIREFRINGENCE OF INJECTION MOLDED LENSES
Huai En Lai , Pei Jen Wang, May 2008
Injection-molded lenses have been widely employed for portable consumer products nowadays. A 3D CAE flow analysis program coupled with Generalized Newtonian Fluid (GNF) models based upon polymer melts and measurements of residual birefringence have been conducted for investigation on effects of prominent processing conditions. Furthermore experimental verifications of the predictions on residual stresses are investigated with two example cases of plastic lenses molded by cyclic-olefin-copolymers. Final results have shown that frozen-in shear stresses in terms of residual birefringence levels are mainly contributed by melt temperature and injection speed during the filling stage.The predictions agree well to the experimental measurements.
SIMULATION OF MULTIFILAMENT FIBER SPINNING
Christopher L. Cox , Young-Pyo Jeon, May 2008
We present a nonisothermal multifilament spinning model applied to a variety of polymer and process conditions.The model combines the flow-enhanced crystallization fiber spinning model of McHugh et al. with a generalization of Dutta's multifilament model. The model predicts fiber and quench air properties throughout the fiber bundle. The McHugh FEC model for a single fiber which includes effects of viscoelastic flow and crystallization has been experimentally validated. We compare the multifilament simulation results to experimental measurements. A secondary goal of the current effort is to develop a model which can be executed on a desktop in 2 to 3 hours or lesscontinuing work.
THE EFFECT OF SCREW DESIGN ON THE QUALITY OF INJECTION MOLDING PRODUCTS
Shai Barkai , Samuel Kenig, May 2008
The melt quality and its effect on the final product quality is one of the least studied subjects in the process of injection molding. Consequently the present study is aimed at investigating the plastification stage in injection molding. A general-purpose screw and a barrier type screw were studied with respect to the effect of melt temperature back pressure and screw rotation speed on product quality. Results indicated that the melt temperature and the back pressure are the decisive factor in the case of the general-purpose screw and the barrier screw respectively. Due to the longer residence times in barrier type screws lower temperatures should be used to avoid melt degradation and inferior mechanical properties.
THE EFFECT OF SCREW DESIGN ON THE QUALITY OF INJECTION MOLDING PRODUCTS
Shai Barkai , Samuel Kenig, May 2008
The melt quality and its effect on the final product quality is one of the least studied subjects in the process of injection molding. Consequently, the present study is aimed at investigating the plastification stage in injection molding. A general-purpose screw and a barrier type screw were studied with respect to the effect of melt temperature, back pressure and screw rotation speed on product quality. Results indicated that the melt temperature and the back pressure are the decisive factor in the case of the general-purpose screw and the barrier screw, respectively. Due to the longer residence times in barrier type screws, lower temperatures should be used to avoid melt degradation and inferior mechanical properties.
AN EVALUATION OF DIFFERENT INJECTION MOLDING SCREW DESIGNS AND THEIR EFFECT ON MIXING QUALITY USING AN INLINE MELT CAMERA (I.M.C)
Luke M. Miller , Walter S. Smith , Timothy W. Womer, May 2008
Improved color mixing for injection molding can be improved by different variables. Screw speed melt temperature back pressure barrel temperature profiles screw design dispersion discs etc. can all influence color dispersion. The mixing ability of an injection molding screw is an important element in the finished part quality of a part which is why screw design is the focus of this study. An I.M.C will allow examination of the molten melt stream prior to exiting the die to give a quantitative comparison of different injection molding screw designs.
AN EVALUATION OF DIFFERENT INJECTION MOLDING SCREW DESIGNS AND THEIR EFFECT ON MIXING QUALITY USING AN INLINE MELT CAMERA (I.M.C)
Luke M. Miller , Walter S. Smith , Timothy W. Womer, May 2008
Improved color mixing for injection molding can be improved by different variables. Screw speed, melt temperature, back pressure, barrel temperature profiles, screw design, dispersion discs, etc. can all influence color dispersion. The mixing ability of an injection molding screw is an important element in the finished part quality of a part, which is why screw design is the focus of this study. An I.M.C will allow examination of the molten melt stream prior to exiting the die to give a quantitative comparison of different injection molding screw designs.
PREPARATION AND PROPERTIES OF DYNAMICALLY CURED PE/MAH-G-SEBS/EPOXY BLENDS
Xueliang Jiang , Yinxi Zhang, May 2008
A new method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin was successfully applied in the PP/maleic anhydride-grafted styrene-ethylene butylenes-styrene (MAH-g-SEBS) triblock copolymer and the obtained blends named as dynamically cured PP/MAH-g-SEBS/epoxy blends. The stiffness and toughness of the blends are in a good balance and MAH-g-SEBS was acted as not only an impact modifier but also a compatibilizer. The structure of the dynamically cured PP/MAH-g-SEBS/epoxy blends is the embedding of the epoxy particles by the MAH-g-SEBS.
PREPARATION AND PROPERTIES OF DYNAMICALLY CURED PE/MAH-G-SEBS/EPOXY BLENDS
Xueliang Jiang , Yinxi Zhang, May 2008
A new method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin was successfully applied in the PP/maleic anhydride-grafted styrene-ethylene butylenes-styrene (MAH-g-SEBS) triblock copolymer, and the obtained blends named as dynamically cured PP/MAH-g-SEBS/epoxy blends.The stiffness and toughness of the blends are in a good balance, and MAH-g-SEBS was acted as not only an impact modifier but also a compatibilizer.The structure of the dynamically cured PP/MAH-g-SEBS/epoxy blends is the embedding of the epoxy particles by the MAH-g-SEBS.
VVARIABLE MOLD TEMPERATURE FOR IMPROVING SURFACE QUALITY OF MICROCELLULAR INJECTION MOLDED PARTS USING INDUCTION HEATING TECHNOLOGY
Shia-Chung Chen , Jeng-Sheng Huang , Ping-Shun Hsu , Jui-Pin Yang , Ho-Hsiang Wang, May 2008
In this study a variable mold temperature method via induction heating combined with water cooling was used to improve surface quality of microcellular parts. It was found that the surface roughness can decreases from 25?¬m to 6.5?¬m when mold surface temperature increases from 100?øC to 160?øC. The flow marks of gas bubbles on the part surface can be removed completely at mold temperature of 160?øC. When the mold temperature over a critical value about 180?øC the surface roughness can reach a saturated value about 5?¬m. Compared to conventional water heating with initial In 60?øC mold temperature surface roughness can be greatly improved by about 80% without a significant increase in cycle time.
EVALUATION OF MOLECULAR ORIENTATION IN POLYSTYRENE BY LASER RAMAN SPECTROSCOPY
Koji Yamada , Kiyotaka Tomari, May 2008
Molecular orientation in injection molded polystyrene was investigated by polarized laser-Raman spectroscopy. The relative intensity ratio of two specific peaks in a spectrum was determined as Orientation Index Ior in accordance with an earlier report. Two kinds of orientation peak along the depthwise direction were found in a section of the molded specimen. This result is qualitatively consistent with the orientation model presented by Tadmor. Polarized laser-Raman spectroscopy was applied to a weldline region in which molecular orientation is supposed to be one of main factors to reduce its mechanical properties. The degree of molecular orientation increased along the flow direction in the case of adjacent flow weldline occurring behind an obstructive pin in the flow channel. This means that the orientation along the weldline in the area near the pin is relatively low. The tensile strength of the area nearest to the pin was higher than that of the downstream area despite the fact that the surface V-notch was deepest. This fact insists that the molecular orientation affects significantly to the mechanical properties of weldline in injection moldings.
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