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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A Study of Filled Volume in a Co-Rotating Twin-Screw Extruder Using Analysis of Residence Time Distribution
The co-rotating twin-screw extruder is a mixing vessel with a certain free volume. The actual filled volume inside the extruder is expected to change at different screw speeds and at different feed-rates. The screw configuration plays a role in the actual filled volume in the extruder. Hitherto, the precise determination of the filled volume, a matter of great importance to understand the process, was not practical. A method based on using Residence Time Distribution (RTD) to determine filled volume is developed and presented in the form of a simple block diagram. The changes in filled volume at different conditions become the basis for a mathematical model for the twin-screw extruder.
High Thermal Conductivity of Thin-Wall Injection Molded Parts for Novel Polymer CompositesI
The processability and higher-order structure of thin-wall parts with ceramics filled polymer composites as a matrix polymer of poly(butylene terephthalate) (PBT) were investigated to produce new polymer composites with high heat diffusivity. Effects of boron nitride (BN) particles, aluminum oxide (Al2O3) and aluminum nitride (AlN) fibers composition and process parameters on processability, thermal property, and internal morphology of parts were discussed. Thermal diffusivity and thermal diffusivity increased concomitantly with increasing ceramic contents. In the case of AlN fiber, the thermal property was dependent upon the polymer and AlN fiber orientation. It is important to control the AlNorientation for improvement of heat-release characteristics. Overall, high processability and thermal properties were achieved using the polymer/AlN composites.
Application of Design of Experiments Methodology in the Kinetics of EPDM vulcanization reaction
The vulcanization kinetics of EPDM is studied using Differential Scanning Calorimetry (DSC) method. An unusual endothermic peak is found over the range of temperature where the vulcanization peak (exothermic event) occurs. Therefore, this study uses a methodology based on Design of Experiments (DOE) to determine and analyze the effect of the different additives present on the compound considering four response variables: Number of peaks presented in the range of vulcanization temperature (between 90°C and 250°C), initial and final temperature of the vulcanization peak, and the value of the heat of vulcanization. This methodology can be extrapolated to thermoplastic and thermoset material and helps to determine in an economic way the thermal effect of additives on thermal processing variables.
Plasticized Polyoxymethylene Performance in Fuels
Polyoxymethylene (POM) or polyacetal is an engineering thermoplastic resin that has been used for the past 50 years, primarily in injection molded articles. POM’s benefit is derived from its strength, stiffness, toughness, lubricity and inherent chemical resistance. This combination of properties has made standard POM a preferred material for applications involving fuel exposure — both in gasoline and diesel fuels. An innovative development has led to the introduction of plasticized POM, a material that has substantially increased flexibility and improved low-temperature performance versus standard POM. This paper details the properties of this new material and explores the performance of extruded tubing in different fuels.
Heat and Scratch Resistant Crosslinkable Thermoplastic Polyurethanes
Thermoplastic polyurethanes (TPU) offer high tensile strength, good low temperature flexibility, and excellent abrasion resistance. In this paper, we describe a novel route to prepare a crosslinkable TPU that can be processed with a conventional extruder. The extruded film can then undergo a photo-crosslinking step to yield a crosslinked material with enhanced heat and scratch resistance. This novel TPU combines the ease of processing of thermoplastics and excellent heat and scratch resistance of thermoset resins. It may be used as protection film in exterior and interior applications.
Polyurea-b-Polyimide block copolymer Coatings: Electrochemical Impedance and Dynamic Mechanical Studies
The corrosion resistance and diffusivity of Polyimide-b-polyurea copolymer coatings was significantly improved by the addition of polyurea, characterized by electrochemical impedance spectroscopy (EIS) in 3.5 wt% NaCl solution. The effect of polyurea on the damping ability of the coatings was studied by dynamic mechanical analysis (DMA). The hydrophobicity of coatings was determined by water contact angle. With increasing polyurea concentration, the corrosion inhibition, hydrophobicity and durability of coatings were remarkably enhanced, and the optimized copolymer was constituted of 50 mol.% polyurea. The incorporation of polyurea also decreases the damping ability due to the restriction of polymer chain motion by hydrogen bonding.
New PCT Compound for LED Reflector Resin
Light-emitting diodes (LED), as a new light source, are being used more and more as display backlight and general lighting. Due to the increase of brightness and electrical current of LED packaging (PKG), there are demanding requirements of LED reflector resins on heat and light stability. A high performance polyester poly(1,4- cyclohexylenedimethylene terephthalate) (PCT) compound has outstanding reflectance stability under heat and light, enabling medium power LED PKGs for applications such as backlight in LCD televisions. In this paper, a new PCT compound is discussed in detail in the context of a LED reflector resin, and performance compared with high temperature polyamide compounds. The processing conditions for injection molding are also discussed.
Polymorphism in Poly(Etherketoneketone) (PEKK) High Performance Thermoplastics
High-performance thermoplastics represent the most promising candidates for the adoption of engineering resins into high demanding applications. Hence, the fundamental understanding of their structure and its effect on their expected performance in critical environments is crucial for the development of new technologies and complex processing techniques. This study provides a detailed evaluation of the morphology of poly(etherketoneketone) (PEKK), focusing on the polymorphic behavior observed in these materials when subjected to controlled heat treatment. The results presented here offer a general overview of the morphological changes observed in these systems at elevated temperatures, providing insight on the expected performance of PEKK materials in high demanding applications. We anticipate that precise control over these morphological changes is critical for the successful introduction of PEKK and other high-performance engineering resins in applications such as aerospace and oil and gas exploration among others.
High Flow Improved Mold Release PC/ABS Blend For Automotive Applications
Polycarbonate and poly(acrylonitrile butadiene styrene) (PC/ABS) blends are the material of choice for automotive applications in both interior and exterior trims, largely due to the combination of easy processability and good physical/mechanical properties. Recently, there is an emerging trend for higher heat and higher flow materials in addition to existing stringent long term stability requirements. To respond to this market need, developmental efforts have been under way to formulate a PC/ABS blend which meets these requirements, and this paper shall address the various aspects of the same. The use of proprietary blends technology has led to the development of a solution that exhibits improved processing characteristics in terms of flow and superior mold release.
Quantitative Prediction of Miscibility Between LDPE and LLDPE in The Blends
Low-density polyethylene (LDPE) is generally blended into linear low-density polyethylene (LLDPE) to improve the processability and optical properties of blown films. The miscibility between the blend components is one of the important factors determining the extent of improvement in these characteristics. In this study we developed a method to calculate the immiscibility index between different LLDPE and LDPE resins based on van Gurp-Palmen plots. An attempt was made to correlate the immiscibility index with the optical properties of the blown films.
Eco-friendly Bio-based Adhesive Tapes made from Biomass Materials
There are some bio-based plastic films however some properties of the films should be modified to use as adhesive tape film and adhesive compound materials should be designed. We improved film properties by adjusting the sheeting process. Regarding the film, it was confirmed that poly lactic acid (PLA) film, which has good heat resistance and tear strength, was obtained by using the calendar sheeting process. On the other side, low glass transition temperature materials and crosslinking materials were selected and formulated for adhesive polymers. Developed bio-based adhesive tape was evaluated and compared to conventional acrylic adhesive tape, and comparable properties were obtained. In addition, in the case of surface protection tape, it indicated enhanced properties. We can introduce Eco-friendly Bio-based Adhesive Tape made from biomass materials.
Review of Titanium Dioxide Ability to Scatter Light
ne of the most popular pigments used for plastic film applications is titanium dioxide, TiO2. Titania-based pigments are popular because of several desirable properties. For example, TiO2 is preferred in plastics applications because it is non-toxic and a relatively inert material. In addition, TiO2 does not migrate in a polymer matrix and generally does not require large shear forces to disperse it into a polymer melt when properly treated. TiO2 morphology can be adjusted so as to attenuate different wavelengths of light for plastic end uses. This attenuation is often referred to as “opacity” within the TiO2 industry. This paper describes the relationship of opacity as a function of titanium dioxide concentration, the thickness of the plastic matrix and the opacity performance.
Improved Impact-Modified Polyoxymethylene Co-Polymers for use in Small Off-Road Engine (SORE) Gas Tank Applications
Ticona has developed a new family of impact-modified polyoxymethylene (POM) co-polymers that demonstrate a combination of improved permeation resistance, cold temperature impact strength, and melt strength that make them suitable for use in the small off-road engine (SORE) gas tank sector. The unique properties of the new products have been achieved through the modification of the polymer backbone, along with the use of a specific coupling technology. The new grades provide a monolayer tank solution with enhanced permeation resistance and impact strength for a variety of injection molding and blow molding small off road fuel tank applications.
Controlled Rheology Polypropylenes for Processes and Applications Requiring High Melt Strength
Polypropylene (PP)-based materials find limited use in applications requiring high melt strength, but chemical branching overcomes this deficiency. This work demonstrates that combining branching and controlled rheology (CR) technologies results in PP-based resins with unique combinations of rheological and material properties. PP resins ranging from 1-12 MFR and exhibiting improved melt strength at low stress combined with viscosity responses comparable to CR PP under high stress will be presented. The ability to control PP melt strength at constant MFR while maintaining high stress viscosity comparable to PP is presented. HMS-PP with PP homopolymer tensile properties and PP random copolymer flexural properties is demonstrated.
Effect of Hot Air on Surface and Mechanical Properties of EPP Products Molded in Steam Chest Molding Machine
In a steam-chest molding machine, the processing temperature and its variation across the mold is strongly affected by the steam pressure. In order to fundamentally resolve this problem and reduce the sensitivity of the temperature to the pressure variation inside the mold, this work proposes the addition of hot air to steam. The hot air was supplied into the steam line using annular port to create good mixture of steam and hot air prior to their introduction into the mold entrance. The effects of hot air flow rate, pressure and temperature were investigated and the surface roughness and mechanical properties of the molded products were characterized. The results showed that the introduction of hot air at the highest available flow rate of 120 liters/min decreased the total heating time by about 32 % and also resulted in a decrease of 12°C in the processing temperature at the surface of the molded part compared to parts molded with pure steam. The surface roughness of expanded polypropylene (EPP) molded parts with hot air mixed with steam reduced by 50%. The tensile property results showed that the difference in strength across the sample thickness was below 4 % when higher hot air flow rate was employed. The results of this work reveal the potential application of hot air in the steam-chest molding process to produce EPP bead products with improved surface quality, enhanced mechanical properties and shortened cycle time resulting in reduced operating cost.
Methodology for the Determination of the Biaxial Measurements of Plastic Materials in a Universal Testing Machine
The objective of this work was to design an experimental test for monitoring the plug force applied on a polymer sheet during the thermoforming process. The design consists in adapting a temperature controlled chamber to an universal testing machine in order to simulate the sheet heating and, to register the sheet strain deformation by a plug penetrating at a controlled rate. It was observed that a proper selection of the sheet heating system affects the penetration force during biaxial measurements as well as the sheet thickness distribution.
Vandar® High Impact Strength Polyester for Sporting Goods
andar® 2100 is an impact modified engineering thermoplastic resin developed to deliver consistent performance over a wide range of temperature and humidity conditions, primarily in injection molded articles. Vandar 2100 provides outstanding ductility and stiffness combined with the excellent chemical and environmental resistance properties of polyesters. The unreinforced and higher flexibility Vandar® grades fill the property gap between standard thermoplastic polyesters and elastomers. These plastics are easy to process including by injection molding and retain their impact strength down to -30 °C.
Applying Ant Colony System Algorithm in the Navigation Process for Mold Manufacturing Scheduling Optimization
Under the CAD software architecture, this study aims to develop navigation processes for mold manufacturing scheduling optimization. Mold manufacturing is a job-shop scheduling problem, with components processing sequence under limited conditions. Using the searching capabilities of the ant colony system (ACS), this study conducts optimization computation of the mold manufacturing scheduling problem, in order to shorten the mold manufacturing time and achieve the objectives of reducing production costs and enhancing competitiveness, while exploring mold manufacturing planning restrictions and manufacturing resources’ effectiveness. This study completes the algorithm steps and manufacturing process time estimation by operations on the navigation interface, and uses mold manufacturing scheduling to make optimized arrangements of finished components. The method can comply with the on-site manufacturing processes, improve scheduling prediction accuracy, and consistently and efficiently integrate the optimization scheduling system and mold manufacturing system. Visualized information of the scheduling results can be provided, thus allowing production management personnel to ensure smooth scheduling.
The Study for Tagushi Method on the Design of Core Plate and Support Pillar
This study explored the structural characteristics of the entire mold in the plastic injection molding process, conducted experiments by changing the core plate thickness, number and position of support pillars, and measured the strain value of the core plate deformation during the injection molding process using a strain gauge. In addition, by combining CAE (Computer Aid Engineering) software, this study verified the experimental and simulated trends’ accuracy before adding the Taguchi method for the analysis of the simulated experimental design planning. We used CAE to analyze the deformation of core plate under different parameters and studied the core plate thickness optimization and support pillar effectiveness without damaging the plastic mold to further enhance the overall mold design.
Effect of Non-Covalent Chemical Modification on the Electrical Conductivity and Tensile Properties of Poly(methyl methacrylate)/Carbon Nanotube Composites
Non-covalent chemical modification by initiated chemical vapor deposition technique is applied to carbon nanotubes to reduce average agglomerate size of the nanoparticles in the polymer matrix and to improve surface interaction between the composite constituents. Carbon nanotube (CNT) surfaces are coated conformally with thin poly-glycidyl methacrylate (PGMA) polymer film and coated nanoparticles are incorporated in poly(methyl methacrylate) (PMMA) polymer matrix using solvent casting technique. Conformal PGMA coatings around individual nanotubes were identified by SEM analysis. TEM and optical microscopy analyses show homogeneous composite morphology for composites prepared by using PGMA coated nanotubes. FTIR and XPS analyses show the successful deposition of polymer with high retention of epoxide functionality. PGMA coating of carbon nanotubes exhibits improvement in electrical conductivity and tensile properties of PGMA-CNT/PMMA systems when compared with uncoated nanoparticles.
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