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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Prediction of Complex Dynamic Behavior from Simple Deformations
Many researchers have noted that characterizations based on sinusoidal tests alone provide misleading information regarding materials used in non-sinusoidal periodic applications. However, availability of commercial instruments that can evaluate materials in complex periodic deformations is rare. To address this problem, various nonsinusoidal periodic deformations are applied to a nitrile elastomer using a torsional rheometer and suitable modeling is employed to predict the behavior. Also it is shown that complex dynamic behavior can be predicted from simple deformations.
Capturing PVT Behavior of Injection-Molded Parts Using Hybrid Methods
Polymer crystallization is the primary mechanism for shrinkage in semi-crystalline molded parts. Injection molding CAE utilizes PVT data to provide information about crystallization. Conventional PVT measurements do not reflect the true shrinkage behavior of the plastic because they do not subject the polymer to the same kind of thermal history as seen in the actual molding process. We introduce a novel hybrid technique to characterize the PVT relationship of molded parts, which accounts for cooling rate effects.
Structure Property Correlations in a New Rigid Rod Luminescent Conjugated Polymer, Polypyridine
Poly(2,5-pyridine diyl) is found to be a unique conjugated polymer in that it is a truly rigid rod polymer whilst being solution processible. It is a highly crystalline polymer with strong interchain interaction, yet is also highly luminescent. The structural properties of this most interesting material are presented together with the physical properties that ensue
Crystallization and Morphology of Propylene/Pentene Random Copolymers
Crystallization and melting behavior of propulene/1-pentene random copolymers were studied. WAXD and d.s.c. measurements of isothermal crystallized samples confirm that the copolymers contain the ? crystal form in large quantity. The content of ? form increases with increasing pentene content and crystallization temperature. We found a limitation in the relative ? content around 60-65%. The efficiency of pentene comonomer is much higher than of ethylene. The equilibrium melting point decreases with pentene content in a non-linear fashion and the values are much lower than the theoretical ones.
A New High-Performance LLDPE for Blown Film Applications
Conventional Ziegler-Natta catalyzed LLDPEs combine good mechanical properties with moderate processability. Efforts to enhance LLDPE properties further, through metallocene catalysts for example, generally result in a processability penalty. The present work describes a new development in LLDPE technology which produces resins with significant improvement in mechanical properties without sacrificing processability. Detailed blown film results show the performance improvement achieved by the new resins, compared to conventional LLDPEs, and the downgauging potential offered by the property improvement.
The Effects of Slip and Antiblock Additives on the Oxygen Transmission Rate of Highly Permeable Polyolefin Plastomer Films
Slip and antiblock additives were determined to reduce significantly the oxygen, carbon dioxide, and water vapor transmission rates for highly permeable blown films made from polyolefin plastomers. At typical usage levels of 2500 ppm erucamide slip and 5000 ppm SiO2 antiblock, for example, oxygen transmission through a 0.8965 g/cm3 plastomer film is approximately 25% less than through a film containing no slip or antiblock additives.
Structure Versus Rheological Properties of Soft Plastics: The Case of Ep(D)M Polymers
In the world of polymers, EP(D)M's are considered as rubbers capable to become excellent elastomers upon vulcanization. This paper presents EP(D)M's as unique soft plastics and provides some basic relationships between molecular structure of EP(D)M and rheological properties as measured by dynamic mechanical spectrometers. The rheological properties discussed, primarily tan delta, affects greatly the processability of rubbers as well as of plastics which are not rubbers.
The Effects of Ultrahigh Shear Rates on Mechanical Properties
The industry has yet to determine the effects of ultrahigh shear rates during the injection molding process. During this research, an ultrahigh shear rate mold will be built and used to exceed a given materials shear rate limit. After regrinding the sheared and unsheared materials, a test specimen will be molded. Samples will be tested for mechanical properties. Comparisons will then be made and a shear rate limit for a given filled or unfilled material will be determined.
Effect of Blending of Styrenic Block Copolymer on Abrasive Wear of Thermoplastic Elastomers (TPEs)
An experimental investigation has been conducted to assess the role of a styrenic block copolymer in modifying the wear properties of high performance thermoplastic elastomers. The TPEs which were evaluated are a polyurethane elastomer and a polyester elastomer. It was found that small amounts of the styrenic block copolymer increased the abrasive wear of these blend elastomers.
Modeling the Structural Evolution of Filled Polymers and Nanocomposites
We simulate the motion of spherical particles in a phase separating binary mixture. We show that the addition of hard particles significantly changes both the speed and the morphology of the phase separation. The domain growth rate shows a nontrivial dependence on the particle density, in qualitative agreement with earlier experimental data. The results facilitate the development of filled polymers and nanocomposites for specific technological applications.
Nanoparticle Reinforcement of Nylon 6,6 Composites
Polymers have traditionally been reinforced with micron-sized fibers and fillers to improve their load-bearing capacity and/or thermal resistance. While generally cost-effective and structurally adequate for many applications, these materials usually lack good appearance and easy processing due to the relatively large size of the dispersed phase. Such disadvantages can be overcome by reducing particle size to nanoscale dimensions through several routes, including the delamination of certain mineral fillers.
Customer Satisfaction: Your Strategic Roadmap to Enhanced Business Performance
Satisfying your loyal customers is the best way to maintain and grow a strong business. By quantifying you performance on the critical factors defining customer satisfaction, you can focus company resources to increase profits, expand in the most attractive markets, and prevent defections. In addition, it reveals unique competitive opportunities to maximize your market position and image. This highly effective approach was developed by the authors and used successfully in North America and Europe with many companies throughout the plastic industry.
Design of a Pressure Vessel of Oriented Polyolefins
The scope of this project is to design and evaluate a plastic package for a product that generates internal pressure. The package will be made of a polyolefin that is capable of being oriented. The mechanical properties of the oriented polyolefin will be characterized. The data then will be used in a finite element package to optimize the package design and predict the final performance of the package.
Investigation of Methods Used to Determine Ejection Temperature for Injection Molding
This paper presents a study on the different methods used to determine the ejection temperature applied to calculating the cooling times during processing of thermoplastic materials. These methods for determining ejection temperature are contrasted with each other and then compared to PVT data. This was done to determine whether or not PVT graphs could provide a reasonable estimate, or alternative, of determining ejection temperature.
Comparison of Extrusion and Injection Blow Molded Bottles
Processing decisions are often made between blowing bottles by the extrusion or injection blow molding technique in companies having both capabilities. Where parison melt strength is not a problem, one of the major considerations is the strength of the resulting bottle. Using the same bottle geometry and same plastic material under optimum processing condition for each method tensile testing will be performed. The tensile specimens will be die cut from side wall panels and compared. Results will shoe the mechanical differences generated by the two approaches.
Cooling Rate Effects on Shrinkage
This paper presents a study on the how cooling rate can produce variations in a plastic materials Pressure - Volume - Temperature (PVT) characteristics which are used in creating shrinkage data for injection molding simulation programs. Most of the currently available PVT data is created using a cooling rate of only 3° C/min. The problem with this data when used to predict shrinkage is that during injection-molding, materials experience much faster cooling rates. This paper presents a study on whether these variations in cooling rates significantly effect the shrinkage values used by mold filling analyses
Effects of Energy Director Geometry and Contamination on Ultrasonic Welds
A primary function of ultrasonic welding is to join two or more pieces of plastic together by means of a high frequency sound energy transferred into mechanical energy, thus producing heat adequate to generate a permanent bond. This frequency (20,000 Hz) is focused onto a specific geometric point on the pieces being welded. When properly designed and implemented, the two pieces will form a permanent structure. The geometry of the parts is a critical aspect of the finished product as is the cleanliness of the parts.
Effect of Notch Size" on Falling Impact of PC Sheet"
How do notch's or grooves in Polycarbonate sheet effect the flexural impact properties of that material? A method was developed to study the effect of notch size" in a falling impact experiment. An apparatus was made to drop a one inch in diameter ball bearing from various heights onto "notched" samples of PC. "Notches" were introduced into the PC sheets by drilling various diameter holes vertically. Results were compared to Notched Izod Impact values of the materials tested."
Synthesis of Epoxy-Clay Nanocomposites
Epoxy-clay nanocomposites have been synthesised by swelling an organo treated clay in a diglycidyl ether of bisphenol A resin (DGEBA) with subsequent polymerisation using different curing agents. The resultant nanostructure was shown to depend on the reactivity of the curing agent but also on the cation exchange capacity of the clay. Characterisation of the different nanostructures was performed by X-ray diffraction and transmission electron microscopy.
A New Synthesis Method of Soluble Starlike C60 Bonding Polymers
The iniferter technique was applied to synthesis of the novel starlike C60 bonding polymers. Fullerene C60 with pendent N,N-diethyldithiocarbamate groups (C60-SR) was used as polyfunctional photoiniferter. The effects of UV irradiation time and ambient temperature on the molecular-weight of polymers were investigated. The photopolymerizations with C60-SR proceeded via a living radical mechanism, and gave soluble polyfunctional polymers (photoiniferters). Multiple polymer arms are attached the C60 core. C60-SR and the polymers obtained by C60-SR could also act as an excellent cross-linking agent.
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