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THIN NANOCELLULAR PLASTIC SHEET WITH PATTERNED FOAMING
Junya Kojima , Tomoyuki Takada , Yoshiharu Nishikori , Hiroyasu Tachibana , Fumio Jinno, May 2008
A thin nanocellular plastic sheet with a designed foaming pattern which is difficult to prepare using the supercritical CO2 foaming method has been developed using a photochemical foaming technology. For this purpose a new acrylic polymer with t-butyl ester groups that produce the foaming gas by chemical reaction is introduced. With this technology foaming of the plastic can be controlled by ultraviolet irradiation and heating. A large-format nanocellular sheet can be manufactured in a continuous process.
THIN NANOCELLULAR PLASTIC SHEET WITH PATTERERNED FOAMING
Junya Kojima , Tomoyuki Takada , Yoshiharu Nishikori , Hiroyasu Tachibana , Fumio Jinno, May 2008
A thin nanocellular plastic sheet with a designed foaming pattern, which is difficult to prepare using the supercritical CO2 foaming method, has been developed using a photochemical foaming technology. For this purpose, a new acrylic polymer with t-butyl ester groups that produce the foaming gas by chemical reaction is introduced. With this technology, foaming of the plastic can be controlled by ultraviolet irradiation and heating. A large-format nanocellular sheet can be manufactured in a continuous process.
MEASURING DISTINCTNESS OF IMAGE OF HIGH GLOSS SURFACES
Dieter P. Gruber , Michael Buder-Stroisznigg, May 2008
Human eye-apparatus notices varying distinctness of image (DOI) of glossy surfaces very accurately. Therefore high resolving measuring techniques are required. This paper aims on presenting the Intensity Profile Analysis (IPA) a novel methodology for the measurement of distinctness of surface reflected images. IPA enables measuring fine detail reproduction of glossy surfaces with good correlation to standard DOI measurements while featuring considerably enhanced preciseness. IPA is a non-contact technique and therefore applicable for uncured or hot surfaces.
AN ASSESSMENT ON OPTICAL QUALITY OF MOLDED BACKLITE COMPARED TO THERMOFORMED BACKLITE
Chengtao Li, May 2008
Injection molding and thermoforming are common processes in both plastics and automotive industry. A preliminary study was made comparing the quality of large complex transparent and optical rear window parts (automotive backlite prototypes) produced from an injection-compression molding process and a vacuuming thermoforming process. Optical quality on the parts was evaluated in terms of optical clarity (only the haze is discussed in this paper) optical distortion birefringence and stress shape and dimension. It was demonstrated that overall the molded backlites had much better optical quality than the vacuum thermoformed backlites based on the same shape and dimensions. Process recommendation quality control and improvement for large complex optical application of plastic products such as automotive polycarbonate (PC) glazing are given during the discussion.
AN ASSESSMENT ON OPTICAL QUALITY OF MOLDED BACKLITE COMPARED
Chengtao Li, May 2008
Injection molding and thermoforming are commonprocesses in both plastics and automotive industry. Apreliminary study was made comparing the quality oflarge, complex, transparent, and optical rear window parts(automotive backlite prototypes) produced from aninjection-compression molding process and a vacuumingthermoforming process. Optical quality on the parts wasevaluated in terms of optical clarity (only the haze isdiscussed in this paper), optical distortion, birefringenceand stress, shape and dimension. It was demonstrated thatoverall the molded backlites had much better opticalquality than the vacuum thermoformed backlites based onthe same shape and dimensions. Process recommendation,quality control and improvement for large complex opticalapplication of plastic products, such as automotivepolycarbonate (PC) glazing, are given during thediscussion.
MELT FRACTURE OF LINEAR POLYETHYLENES: MOLECULAR STRUCTURE AND DIE GEOMETRY EFFECTS
Mahmoud Ansari , Savvas G. Hatzikiriakos, May 2008
The melt fracture polymer extrusion instabilities are studied primarily as functions of the geometrical details of die (cylindrical slit and annular) and molecular structure of polymers. Experimental observations concerning the flow curves the critical wall shear/extensional stresses for the onset of the instabilities and the effects of geometry and operating conditions are presented for two linear polyethylenes mainly highdensity polyethylenes (HDPEs). It is found that sharkskin and other melt fracture phenomena are sensitive to details of the molecular weight distribution (MWD). It is also found that critical conditions for the onset of various melt fracture phenomena depend significantly on the type of die used for their study. For example sharkskin melt fracture in slit and capillary extrusion was obtained at much smaller critical shear stress values compared to those found in annular extrusion. Such observations explain the lack of correlation between experimental results from the laboratory and the full scale process.
MELT FRACTURE OF LINEAR POLYETHYLENES: MOLECULAR STRUCTURE AND DIE GEOMETRY EFFECTS
Mahmoud Ansari , Savvas G. Hatzikiriakos, May 2008
The melt fracture polymer extrusion instabilities are studied primarily as functions of the geometrical details of die (cylindrical, slit and annular) and molecular structure of polymers. Experimental observations concerning the flow curves, the critical wall shear/extensional stresses for the onset of the instabilities and the effects of geometry, and operating conditions are presented for two linear polyethylenes, mainly highdensity polyethylenes (HDPEs). It is found that sharkskin and other melt fracture phenomena are sensitive to details of the molecular weight distribution (MWD). It is also found that critical conditions for the onset of various melt fracture phenomena depend significantly on the type of die used for their study. For example, sharkskin melt fracture in slit and capillary extrusion was obtained at much smaller critical shear stress values compared to those found in annular extrusion. Such observations explain the lack of correlation between experimental results from the laboratory and the full scale process.
EXTRUSION-ASSISTED DIRECT-FOAMING ROTATIONAL MOLDING PROCESS
Kimberly Christian , Emad Abdalla , Gregory Eberle , Remon Pop-Iliev, May 2008
This paper focuses on the evolution and experimental validation of the novel patent-pending Extrusion-Assisted Rotational Foam Molding (EARFM) process intended for the fabrication of high quality integral-skin fine-celled foamed-core polyolefin moldings. The process innovatively conjoins the traditional rotational foam molding technology with extrusion melt compounding in a deliberate attempt to reduce the principal intrinsic disadvantages associated with rotational foam molding i.e. the energy intensive and very lengthy processing cycles. A lab-scale custom-made heavy-duty experimental setup along with three mold shape variations (cylindrical flat plate and container-like) have been designed and built. It was used for conducting a comparative experimental process validation by using all three mold designs for processing integral-skin foamed core polyethylene (PE) parts. The process control optimization included resin formulation optimization direct foaming concept implementation for process simplification and mold venting system re-design. The thereby modified process resulted in even shorter processing cycle times lower energy consumption and improved foam morphologies.
EXTRUSION-ASSISTED DIRECT-FOAMING ROTATIONAL MOLDING PROCESS
Kimberly Christian , Emad Abdalla , Gregory Eberle , Remon Pop-Iliev, May 2008
This paper focuses on the evolution and experimental validation of the novel patent-pending Extrusion-Assisted Rotational Foam Molding (EARFM) process intended for the fabrication of high quality integral-skin fine-celled foamed-core polyolefin moldings. The process innovatively conjoins the traditional rotational foam molding technology with extrusion melt compounding in a deliberate attempt to reduce the principal intrinsic disadvantages associated with rotational foam molding, i.e., the energy intensive and very lengthy processing cycles. A lab-scale custom-made heavy-duty experimental setup along with three mold shape variations (cylindrical, flat plate and container-like) have been designed and built. It was used for conducting a comparative experimental process validation by using all three mold designs for processing integral-skin foamed core polyethylene (PE) parts. The process control optimization included resin formulation optimization, direct foaming concept implementation for process simplification, and mold venting system re-design. The thereby modified process resulted in even shorter processing cycle times, lower energy consumption, and improved foam morphologies.
MORPHOLOGICAL AND MECHANICAL CHARACTERISTICS OF RIGID POLYURETHANE FOAMS
Nora Catalina Restrepo-Zapata , E. Alexander Ossa H. , Felipe Cano Mejia, May 2008
Cellular materials are formed by solid cells in a gaseous core. They exhibit good strength to mass ratio and they are used as insulators and as a core in sandwich composite manufacture. This work describes an extensive study on the structure and physical-mechanical properties of rigid polyurethane (PU) foams. The effect of composition and processing conditions on the mechanical properties were studied. Morphology specific strength and density were evaluated to determine the optimal levels of processing for a required application. Foam morphology was characterized using stereoscopy and optical microscopy. A basic mechanical property as compression strength was measured in the plateau zone.
MORPHOLOGICAL AND MECHANICAL CHARACTERISTICS OF RIGID POLYURETHANE FOAMS
Nora Catalina Restrepo-Zapata , E. Alexander Ossa H. , Felipe Cano Mejia, May 2008
Cellular materials are formed by solid cells in a gaseous core. They exhibit good strength to mass ratio and they are used as insulators and as a core in sandwich composite manufacture. This work describes an extensive study on the structure and physical-mechanical properties of rigid polyurethane (PU) foams. The effect of composition and processing conditions on the mechanical properties were studied. Morphology, specific strength and density were evaluated to determine the optimal levels of processing for a required application. Foam morphology was characterized using stereoscopy and optical microscopy. A basic mechanical property as compression strength was measured in the plateau zone.
NOVEL NANOBIOCOMPOSITES WITH ANTIMICROBIAL AND BARRIER PROPERTIES OF INTEREST IN ACTIVE PACKAGING APPLICATIONS
M.D. Sanchez-Garcia , E. Gimenez , M.J. Ocio , J.M. Lagaron, May 2008
It is well-known that the nanocomposites technology can significantly enhance among others the thermal mechanical and barrier properties of plastics. It is also known that most bioplastics including the thermoplastic biopolymers have lower than desired levels for certain properties which makes their use in certain packaging applications problematic. The combination of active technologies such as antimicrobials and nanotechnologies such as nanocomposites can synergistically lead to bioplastic formulations with balanced properties and functionalities for their implementation in packaging applications. The present work presents the development and characterization of novel nanocomposites of polycaprolactone (PCL) with enhanced barrier properties and with controlled-release of biocide natural extracts.The antimicrobial nanocomposites of biodegradable materials were prepared in solution by a casting method.The morphology of the biocomposites was visualized by transmission electron microscopy (TEM) and by Atomic Force microscopy (AFM) the thermal properties were investigated by differential scanning calorimetry (DSC) and the solubility and kinetics of released biocide were determined by Attenuated Total Reflection Fourier Transformed Infrared (ATR-FTIR) spectroscopy. Water and limonene barrier properties were also enhanced in the biocomposites.
A STUDY ON THE BLENDS OF HDPE AND LLDPE FOR ROTOMOLDING APPLICATIONS
Alexandra Fabre, May 2008
This paper examines the technical feasibility of using blends of high-density polyethylene (HDPE) with linear-low density polyethylene (LLDPE) for rotational molded underground water tanks application. Various blending ratios were investigated to determine the most optimum stiffness reasonable toughness and low warpage properties required in underground water tanks. Mechanical properties were characterized and determination of miscibility by different methods including zero shear viscosity study DSC analysis and Crystallization rate measurement were done in order to find the suitable ratio of blending. Rotomoldability was checked for this ratio to using vacuum tests. It was found that HDPE/LLDPE blends are miscible in all compositions and that the ratio 70:30 (HDPE:LLDPE) has the most optimum mechanical properties for underground water tanks and also for any load-bearing applications. The resulting warpage after vacuum tests confirmed mechanical characterization. The grade 70:30 with LLDPE MI 1 (g/10 min) can be used for underground water tank applications to increase mechanical properties and to reduce warpage.
HHEATING AND COOLING TECHNOLOGIES FOR INJECTION MOLDING TO IMPROVE PRODUCTS QUALITY
Hai-mei Li , Chang-yu Shen , Shia-chung Chen , Ho- hsiang Wang , Xin Wang, May 2008
Temperature is one of the most important processing parameters in injection molding which has effects on products quality and production efficiency. The relatively assistant heating and cooling technologies to adjust mold and resin temperature during the injection molding processing were discussed including heated water electric heater induction heating and chill water. Firstly the heating/cooling effects on the uniformity of mold temperature field and the time consumption to obtain the ideal processing temperature were considered by experiments. Then the appearance quality of molded parts (surface roughness) produced by the heating/cooling technologies were measured. The residual stress distribution of transparent PC parts made by different cooling rate was examined by photoelastic instruments.Compared with traditional processing it is found that microcellular injection molded specimens average surfaceroughness was reduced from 26 ??m to minimum 5.1 ??mwhen mold temperature above 18  ?? oC ?? From a series ofmulticolored band or fringe pattern it shows that whenmold temperature increase 20 oC ?? ?? ??he stress strip reducedfrom 6 to 2 which meant less residual stress.
HEATING AND COOLING TECHNOLOGIES FOR INJECTION MOLDING TO IMPROVE PRODUCTS QUALITY
Hai-mei Li , Chang-yu Shen , Shia-chung Chen , Ho- hsiang Wang , Xin Wang, May 2008
Temperature is one of the most important processing parameters in injection molding which has effects on products quality and production efficiency. The relatively assistant heating and cooling technologies to adjust mold and resin temperature during the injection molding processing were discussed, including heated water, electric heater, induction heating and chill water. Firstly, the heating/cooling effects on the uniformity of mold temperature field and the time consumption to obtain the ideal processing temperature were considered by experiments. Then the appearance quality of molded parts (surface roughness) produced by the heating/cooling technologies were measured. The residual stress distribution of transparent PC parts made by different cooling rate was examined by photoelastic instruments. Compared with traditional processing, it is found that microcellular injection molded specimens average surface roughness was reduced from 26?m to minimum 5.1?m when mold temperature above 18? oC? From a series of multicolored band or fringe pattern, it shows that when mold temperature increase 20 oC???he stress strip reduced from 6 to 2, which meant less residual stress.
SOLID STATE SHEAR PULVERIZATION AND CHEMICAL RECYCLING OF POLYMERS
Hossein Hosseini , Mohammad Mosaddegh , Behzad Shirkavand-Hadavand, May 2008
Solid state shear pulverization is a novel technology in polymer processing for production of new polymeric materials. By implementation of this technology various processes such as polymer recycling compounding and improving of mechanical-chemical properties of polymers can be enhanced. This is a continuous and one-stage process with low energy consumption. During this process polymers are subject to high pressure and shear forces. In this paper this technology and its applications to polymer processing is perused. At the end recycling of PET wastes by this technology is presented that have higher efficiency in comparison with existing methods.
SOFT THERMOPLASTIC POLYURETHANES
Donald Meltzer, May 2008
The synthesis and physical properties of soft plasticizer-free thermoplastic polyurethanes (TPUs ) exhibiting durometers below 70A on the Shore scale have been investigated. The TPUs have been further characterized in terms of their thermal and tensile characteristics set and tear properties as well as density. By employing hydrocarbon polyols along with suitable chain extenders aromatic TPU with specific gravity less than 1.0 that exhibit acceptable physical properties and exhibit low compression set characteristics have been prepared. Furthermore these TPUs are hydrophobic an unusual characteristic for a TPU which suggests that they could be useful for applications where TPUs would not normally be considered e.g. water barriers.
SOFT THERMOPLASTIC POLYURETHANES
Donald Meltzer, May 2008
The synthesis and physical properties of soft plasticizer-free thermoplastic polyurethanes (TPUs ) exhibiting durometers below 70A on the Shore scale have been investigated. The TPUs have been further characterized in terms of their thermal and tensile characteristics, set and tear properties as well as density. By employing hydrocarbon polyols along with suitable chain extenders, aromatic TPU with specific gravity less than 1.0, that exhibit acceptable physical properties and exhibit low compression set characteristics, have been prepared. Furthermore, these TPUs are hydrophobic, an unusual characteristic for a TPU, which suggests that they could be useful for applications where TPUs would not normally be considered, e.g., water barriers.
EVALUATION OF MULTI-SAMPLE MICRO-CAPILLARY RHEOMETER
Doyoung Moon , Anthony J. Bur , Kalman B. Migler, May 2008
We present a Multi-sample Micro-capillary Rheometer (MMR) which is capable of measurements over a broad range of temperatures viscosities and shear rates. The instrument is simple as the flow is generated by external gas pressure and the shear rate is measured optically. We test the MMR against two National Institute of Standards and Technology (NIST) Standard Reference Materials (SRMs) three low viscosity standards and one commercial polymer (Polydimethlysiloxane Polyisobutylene solution Oils and Polystyrene) and report a high level of accuracy and precision. This instrument will be particularly useful as a combinatorial method and in cases of limited material quantity (typical sample size 20 ?¬L). The dynamic range of the instrument is eightorders of magnitude in viscosity and four orders of magnitude in shear rate.
IMPROVED PROPERTIES AND COST EFFICIENCIES OF CYCLIC OLEFIN COPOLYMER ENHANCED FORMING FILMS
Paul D. Tatarka, May 2008
Cyclic olefin copolymers (COC) can provide film producers and packaging converters with an opportunity to create thermoforming films. COCs are amorphous thermoplastics with excellent moisture barrier high temperature stability and stiffness. Mono- and multi-layer examples of LLDPE-based forming films compared against commercially available products clearly demonstrate how well the addition of COC improves physical properties thermoforming and packaging performance. COC improves material distribution of LLDPE formed trays. These improvements enable the formed tray to withstand higher crushing force. Enhanced performance permits possibility of down gauging.


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