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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Effect of Shear Induced Flow Imbalance on Multi-Cavity Molds using Gas Assisted Injection Molding
This paper presents a study on the effect of shear induced flow imbalances on a thick flanged plate molded with gas assist. Samples were molded with and without melt rotation technology and the results contrasted. Flow imbalances and impact on gas distribution and gas penetration were analyzed. Melt rotation technology corrected the flow imbalances seen in multi-cavity tooling and helped gas penetration and distribution.
Comparison and Optimization of Five-Gallon Container Designs using CAE
The design quality of several five-gallon pails was evaluated using a CAE software. This software simulates the load under actual and worst case storage conditions. According to the results, recommendations were made to improve each design. In addition, the containers properties were measured to analyze the effect of processing conditions on their performance.
Ballistic Impact Resistance of Biaxially Oriented Polypropylene
Biaxially oriented polypropylene (PP) processed by cross-rolling was investigated for application as an improved ballistic resistant material. Cross-rolled PP has greatly improved toughness properties as indicated by both puncture and ballistic tests. Cross-rolling creates a lamellar morphology which is responsible for the unique cone-shape damage mechanism obtained under ballistic deformation conditions.
Polymer-Based Solar Thermal Systems: Past, Present and Potential Products
Conventional solar thermal systems primarily use metal and glass materials and metal-processing technology. Polymers offer potential for reduced costs through lower materials and manufacturing costs, weight reduction and parts integration. This paper reviews past and present polymer solar heating systems, and suggests potential opportunities for development of solar thermal products.
Cold Curing Epoxy Adhesives for Building Applications
Polymers open access to many new production techniques. This also applies for the building industry. CFRPstraps bonded with special cold curing adhesives have become an important technique for the supplementary reinforcement of buildings. For the successful application the specific material behaviour, especially of the adhesive, has to be considered. Thermal application limits were investigated with a method based on DMA-curves. They suggest that often stated values close to the glass transitions temperature for such adhesives should be reconsidered.
Rheology of High Molecular Weight Polyethylenes with SCCO2
The effects of using supercritical carbon dioxide (SCCO2) to melt process high molecular weight polyethylene are studied. High molecular weight polyethylene (HDPE) is studied in an effort to produce high strength fibers and materials in a melt extrusion process. Dynamic, capillary, and slit-die rheometry are used to quantify the effect SCCO2 has on the melt viscosity of high Mw HDPEs. Carbon dioxide uptake is quantified using mass flow measurements.
Development and Use of Eco-Plastics in Mexico and Latin America
In Mexico and other countries of Latin America, the per capita consumption of plastics has more than doubled during the last decade. This results in the increased generation of plastic residues which leads to the growing plastics waste disposal problem. This paper presents a concept of Eco-plastics" which is an integrated approach to solving plastic waste generation challenges in Latin America. A feasibility study is recommended as a first step towards the implementation of this concept."
The Center for Nanocomposites and Multifunctional Materials at Pittsburg State University
This project is a collaborative effort by Pittsburg State University and its partner institutions, University of New Orleans, North Carolina A & T University and a consortium of advisory member companies. It was initiated in the Fall semester of 2004 and received authorization of the Office of Naval Research (ONR) in March 2005. The research topics and activities of the partners focus on implementation of the Multifunctional Materials For Naval Structures" project."
Measurement of Gas Solubility in Polylactide
The solubility of N2 and CO2 in plylactide melt was measured at 180 °C and 200 °C using a magnetic suspension balance. The Simha-Somcynsky (SS) equation of state (EOS) and Sanchez-Lacombe (SL) EOS were applied for the swollen volume prediction to obtain the buoyancy compensation during the determination of the solubility.
Mechanical Behavior of Cured Epoxy: Effects of Ultrasonic Processing
Our recent research suggests that ultrasonic cavitation can be an effective tool for the fabrication of polymer nanocomposites. However, how high intensity cavitation modifies the polymers needs to be understood. We report that cavitation not only enhances the curing rate of a commercial epoxy polymer but also increases the stiffness of the cured sample without lowering the flexural strength. Our results indicate that there is a critical processing time beyond which polymer degradation occurs.
Failure Mode Characterization of Glass Fiber Filled Plastic Using Fractography
Several exemplar fracture surfaces of a glass filled plastic material were studied. The material chosen for this investigation was Noryl® GFN2, a 20% glass fiber reinforced blend of poly(phenylene oxide) (PPO) and polystyrene (PS) from G.E. Plastics. The generated failure modes of this material included tensile overload, flexural overload, impact and fatigue. This paper will focus on identifying potentially unique fracture features for each type of cracking.
Structure and Properties of TPO-Based Nanocomposites
Thermoplastic polyolefin nanocomposites with different ratios of maleated polypropylene (PP-g-MA) to organoclay were prepared in a twin-screw extruder. Mechanical and thermal properties were measured and compared with composite theory. These properties will be discussed in terms of the morphology of the dispersed clay and elastomer phases and the characteristics of the matrix and dispersed phases.
Isothermal Enthalpy Recovery in a Polymer Glass After Carbon Dioxide Jumps
A novel technique to measure enthalpy recovery in polymer glasses after carbon dioxide pressure jumps has been developed in our laboratory. Specifically, we modified a Setaram C80 Calvet differential scanning (DSC) calorimeter to work under moderate CO2 pressures. In the present work, we show first results for such experiments for polystyrene in which the pressure is changed from 4 MPa to 2 MPa, 1 MPa and ambient conditions.
Layered, Nano Foams from PS Blends
This paper reports on the single-phase blend of polystyrene with syndiotactic polystyrene, its fluid phase behavior with CO2, and on the layered and nano foams obtained therefrom.
Experimental Studies and Modeling of Fiber Breakage in Co-Rotating Twin Screw Extruder
An experimental study of glass fiber breakage in corotating twin screw extruder for isotactic polypropylene and polyamide12 is presented. Comparisons are made using different screw configurations, fiber length, diameter, and loading. We have developed a model for the kinetics of fiber breakage and evaluated the kinetic constants for various conditions.The glass fiber breaks up and the fiber length was reduced to a steady state length. The steady state length primarily depends on the screw configurations and initial fiber length.
Mechanical Properties of PP/Ethylene Acrylate Copolymer/TiO2 Blends
An ethylene methyl acrylate copolymer (EMA) produced from a tubular reactor was found to be effective in toughening polypropylene even at low concentrations. The addition of a small amount of TiO2 pigment enhanced the EMA toughening effect. Microscopy and thermal analysis helped to reveal the possible EMA toughening mechanisms. The effects of two processing methods, dry-blending and melt-blending, on the compound mechanical properties were also studied.
Structure Development In Melt Spinning the New Generation of Polyolefins
In the period of the late 1930s to the 1950s, the first generation of polyolefins including polyethylene, isotactic polypropylene and other isotactic polyolefins were introduced. The structures developed in these polymer have since that time been investigated. In the 1990s, polypropylene of various tacticities and new copolymers of ethylene with varying compositions have been introduced. We describe here studies of the structure development of these new polymers during melt spinning processing.
Using sc-CO2 as a Processing Aid for Improving the Properties of Polymer Nanocomposites
Supercritical carbon dioxide (sc-CO2) is used in this work as a processing aid for improving the dispersion of the clay nanoparticles in the melt intercalation process of HDPE-clay nanocomposites. Some preliminary experiments were performed to study the effect of sc-CO2 on the melt intercalation process. Results from the mechanical properties and rheological studies show a direct effect of the sc-CO2, suggesting that the presence of sc-CO2 in the melt blending process can enhance the degree of mixing and the dispersion of the nanoclays into the polymer matrices.
Reactive Extrusion of PBT for Low Density Foaming
Branching or partial cross-linking of polybutylene terephthalate (PBT) resins by reactive modification with multi-functional epoxides was investigated. The rheology of the PBT products could be controlled by varying material and operational conditions of the reactive extrusion process. The modified PBT was adaptable to low density foam extrusion, where higher melt strength is necessary.
Application of Recycled Industrial Polyolefins in Pail Design Using FEM
This paper presents the application of recycled industrial HDPE and PP and their blends with virgin resins in pail design using finite element analysis. Results predict that these blends can be used in pails for the packaging of non food grade materials such as paints, oil and grease.
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