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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Mechanical Properties of High Density Polyethylene - Pennycresss Press Cake Composites
Pennycress press cake (PPC) is evaluated as a bio-based fiber reinforcement. PPC is a by-product of crop seed oil extraction. Composites with a high density polyethylene (HDPE) matrix are created by twin screw compounding of 25% by weight of PPC and either 0% or 5% by weight of maleated polyethylene (MAPE). Tensile, flexural, and impact properties are assessed from injection molded test specimens. An improved PPC bio-filler was produced by solvent treating PPC (STPPC). Composite blends composed of STPPC were superior to their PPC counterparts. Composites made with STPPC and MAPE had significantly improved tensile and flexural properties compared to neat HDPE.
Evaluation of Degradation Characteristics at the Interface Between Glass Fiber and Resin of Glass Fiber Reinforced Plastics for Hot Water Application
Engineering plastics are generally used for parts in the path of hot water in a water heater and a domestic co-generation system. In this research, the long-term performance of short glass-fiber or long glass-fiber reinforced mPPE, and short glass-fiber reinforced PPS were investigated for thermal resistance due to hot water immersion and hot air exposure. The acoustic emission analysis was also conducted to investigate the cause of an initial change in mechanical properties by the bending test and the Izod impact test. As a result, the bending strengths of PPE and PPS after hot water immersion decreased due to degradation at the interface between a matrix resin and a glass fiber.
Additives to Improve Regrind Utilization and Recycling of High Barrier Blow Molded Containers
The ability of maleic anhydride grafted polymers to compatibilize non-polar polyolefin polymers with polar polymers or contaminants has been confirmed and publicized by a number of experts in the field. This study reports on a new generation of random copolymers of ethylene and anhydride functional monomers specifically designed for compatibilizing blends of polyethylene polymers with polar components (other polymers or additives) in mixed recycle streams. The results show that these copolymers, with a very high level of reactive functionality (>3% wt. of anhydride), improve the impact strength of molded or extruded part made from mixed recycle streams containing Polyethylene Vinyl Alcohol (EVOH) or Polyamides (PA) even when the scrap contains high levels of moisture, lubricants or other resins. Two practical examples are discussed: use in regrind layers of extrusion blow molded containers and use in recycling of mixed polymer streams to produce other parts.
Numerical Modeling of Fire Resistance of FRP Composite Fire Wall Panel
A 3.048 m x 3.048 m (10’ x 10’) non-load bearing fire wall panel was tested for its fire resistance according to ASTM E119 standard furnace test. This fiber reinforced plastic (FRP) composite wall panel was found to have 1 hour fire resistance rating. A finite element model was developed to simulate the thermal behavior of the wall panel under the ASTM E119 conditions. COMSOL 4.3a Multiphysics finite element software was used to solve the time-dependent heat and mass balance equations to determine the temperature of the unexposed face of the wall panel. Excellent agreement was found between the results of the numerical simulation and data from the ASTM E119 test indicating the usefulness of the numerical methods in evaluating fire-resistance of structures.
Calculation on the Residual Stresses of Injection-Molded Conductive-Carbon-Fiber-Filled Polymer Composites
In order to improve the conductivity of the molding fabricated with conductive-carbon-fiber-filled polymer composites, we investigated, using layer removal method, the distribution of the residual stresses of injection-molded conductive-carbon-fiber-filled polypropylene in this paper. Integrated effects of conductive carbon-fiber(CCF) orientation and its mass fraction at different positions on the residual stresses of the molding, we calculated the modulus of the molding sample using the classical laminate theory(CLT) of composites, and obtained the residual stresses distribution.
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.
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