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 TECHNIQUE COMPARISON FOR THE QUANTIFICATION OF COLOR CONCENTRATE IN A POLYACETAL COMPONENT
Color concentrates are an important component in many of todayƒ??s thermoplastic applications. When the level of color concentrate varies a small amount from the nominal the result can be a noticeable change in the appearance of the molded part. In this investigation the level of color concentrate present in molded polyacetal parts will be determined and compared using three methodologies. The methods include x-ray spectroscopy gravimetric analysis and ash content. The three methods are compared in regards to the reproducibility of results and the effectiveness of the technique to quantify color concentrate levels.
A TECHNIQUE COMPARISON FOR THE QUANTIFICATION OF COLOR CONCENTRATE IN A POLYACETAL COMPONENT
Color concentrates are an important component in many of today’s thermoplastic applications. When the level of color concentrate varies a small amount from the nominal, the result can be a noticeable change in the appearance of the molded part. In this investigation, the level of color concentrate present in molded polyacetal parts will be determined and compared using three methodologies. The methods include x-ray spectroscopy, gravimetric analysis and ash content. The three methods are compared in regards to the reproducibility of results and the effectiveness of the technique to quantify color concentrate levels.
INVESTIGATION OF THE CORRELATION BETWEEN THERMO-MECHANICAL PROPERTIES AND PERCOLATION THRESHOLD IN CARBON FILLED POLYPROPYLENE NANOCOMPOSITES
This study aims to investigate possible correlation between thermo-mechanical properties and percolation threshold in carbon filled polypropylene nanocomposites. The goal is to identify an indirect way to determine the percolation threshold without the need to measure the electrical conductivity of a plethora of specimens which is a cumbersome task. The percolation threshold is the basic required feedback of all the existing theoretical models that describe the electrical conductivity of composites materials and are used as design tools. Polypropylene is used as the polymer and exfoliated graphite nanoplatelets, carbon black and vapor grown carbon fibers are used as fillers. Electrical conductivity and rheological properties of PNCs are characterized as a function of fillerƒ??s concentration. The need of accurately determining the percolation threshold is demonstrated by comparing the electrical conductivity data to the predictions of the modified Mamunya model for all three systems studied.
THERMAL CONDUCTIVITY OF POLYMERS FILLED WITH NON-ISOMETRIC FILLERS: A PROCESS DEPENDENT ANISOTROPIC PROPERTY
Non-isometric fillers used to raise thermal conductivity of thermoplastics to up to 15 Wm-1K-1 become oriented during the injection molding process bringing new opportunities for thermal management concepts for complete plastic housings. By changing the flow conditions different filler orientation profiles and hence distributions of conductivity values are obtained. A 3- dimensional analytical approach for predicting the thermal conductivities of polymers filled with non-isometric fillers is presented.
THERMAL CONDUCTIVITY OF POLYMERS FILLED WITH NON-ISOMETRIC FILLERS: A PROCESS DEPENDENT, ANISOTROPIC PROPERTY
Non-isometric fillers, used to raise thermal conductivity of thermoplastics to up to 15 Wm-1K-1, become oriented during the injection molding process, bringing new opportunities for thermal management concepts for complete plastic housings. By changing the flow conditions, different filler orientation profiles and hence, distributions of conductivity values, are obtained. A 3- dimensional analytical approach for predicting the thermal conductivities of polymers filled with non-isometric fillers is presented.
The Acoustic Behavior Of Thermoplastic Tribological Pairings
The acoustic behavior of frictional pairings with plastics is dependent on several factors. Next to the matrix materials, polymer modifications as well as tribological and mechanical additives, such as PTFE and glass or carbon fibers, play an important role. At the Chair of Polymer Technology, research on the triboacoustic properties of various frictional pairings (POM, PA, etc.against POM, PA, 100Cr6, etc.) has been conducted. In addition to the material pairing, the influence of system properties such as sliding speed, and contact pressure on acoustic intensity and frequency spectrum were analyzed. This report shows a triboacoustic system and explains the findings and results of conducted tests, which help the engineer, when designing 'squeal-free' or 'low-squeal' frictional pairings with plastics.
INTERPHASE CHARACTERIZATION OF POLYMER NANOCOMPOSITES
The effect of the reinforcement-polymer interphase on the overall performance of the composites becomes more dominant as the size of the reinforcements decreases. The focus of this study is to characterize the interphase of polypropylene nanocomposites. Carbon nanotubes and graphite nanoplatelets are used at concentrations in the range of 0-1 wt%. Nanoindentation, atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used to assess the interphase. The hardness, modulus and topography are measured and the interphase thickness and adhesion between the matrix and nanoparticles are evaluated. Understanding the role of interphase can lead to new design tools for development of advanced polymer nanocomposites.
INVESTIGATION OF THE HEAT HESITATION IN THE IN-MOLD-DECORATION PROCESSING WITH THE FILM
In-mold decoration (IMD) becomes a more and more popular process recently due to its high manufacturing efficiency; therefore, it is important to investigate and realize the complicated process mechanism of IMD. In this study, a PC film is attached to the cavity side for observing the heat hesitation effect. This effect will be compared with that in conventional injection molding (without PC film) both experimentally and numerically.Through the comparison between all experimental and simulation results, we can find both experiments and simulation are in a good agreement.
SIMULATION OF TWIN-SHEET BLOW MOLDING TECHNOLOGY FOR AUTOMOTIVE FUEL TANK INDUSTRY
Extrusion blow molding using cylindrical-shaped parisons has been the process of choice for the production of plastic fuel tanks (PFT) for the automotive industry. A revolutionary process called twin-sheet blow molding is now recognized as an innovative technology for manufacturing PFT. BlowView??, a commercial finite element software developed by the National Research Council Canadaƒ??s Industrial Materials Institute, has now been adapted to simulate this new process type. It supports engineers to sketch and visualize PFT designs resulting from the twin-sheet process, before committing to expensive tooling in manufacturing. Optimization to improve quality, decrease cost, etc., is also under investigation.
POLYCARBONATE-POLYESTER BLENDS FOR HIGH FLOW APPLICATIONS
The following paper describes polycarbonate (PC)- polyester blends that can be used for applications demanding high flow while simultaneously having the ability to process at lower temperatures. The presence of a polyester with a lower glass transition temperature that is miscible with the polycarbonate leads to lower processing temperatures and increasing flow while maintaining transparency. To further increase the flow the molecular weights of the polycarbonate and the polyester are reduced. An expected compromise in impact properties is mitigated by the addition of an impact modifier while maintaining transparency.
INCORPORATION OF SILICONES INTIO WOOD USING SUPERCRITICAL CO2
Wood samples have been impregnated with silicones and subsequently crosslinked in-situ by utilizing supercritical CO2 as a solvent and transport medium. These wood-silicone composites have been exposed to controlled thermo-oxidative conditions under load to determine their time to failure. The time to failure of wood samples has been found to be related to temperature through an Arrhenius type relationship. The addition of silicone to wood significantly increases time to failure suggesting that the silicone is acting as a reinforcing scaffold during the thermal degradation of wood.
COMPLIMENTARY FAILURE ANALYSIS METHODS AND THEIR APPLICATION TO PLASTIC PIPE
A variety of methods can be employed to characterize failure modes of plastics and identify contributing factors. By combining visual and microscopic examination with chemical analysis, the reasons for ductile, brittle, or progressive failure may be determined. This paper provides a comparative analysis based on fractography and spectroscopic analysis of chlorinated polyvinyl chloride (CPVC) pipe samples that failed due to chemical exposure. Chemical degradation and environmental stress cracking failure modes are explored using optical microscopy, scanning electron microscopy, and FTIR.
EFFECT OF INCORPORATION OF DEVULCANIZED RUBBER ON THE PROPERTIES OF A VIRGIN TIRE COMPOUND
In this work, devulcanized rubber obtained from a thermo-mechanical devulcanization process with supercritical carbon dioxide was utilized in a virgin tire compound in order to lower the material cost. Different content of devulcanized rubber from 10 phr to 30 phr was used as part of the rubber in an actual virgin tire compound. Curing characteristics, Mooney viscosity, tensile strength, tear strength, elongation at break, and hardness of different samples were measured in order to evaluate the impact of incorporation of devulcanized rubber in a virgin tire compound. The results show that up to 30 phr devulcanized rubber can be used in a virgin tire compound without any significant deteroriation in compound properties.
PROCESSING AND CHARACTERIZATION OF PEEK/MWNT NANOCOMPOSITES PREPARED BY HIGH POWER ULTRASONIC WAVES
A single screw extruder having ultrasonic barrel attachment was used to manufacture polyetheretherketone (PEEK) - multi walled carbon nanotubes (MWNT) nanocomposites with enhanced dispersion of carbon nanotubes (CNTs) in polymer matrix. The effect of ultrasonic amplitude and CNTs loading on die pressure, electrical conductivity, rheological, morphological and mechanical properties of PEEK filled with 1-10 wt% MWNT was studied. The die pressure was observed to decrease with the increase of ultrasonic amplitude and increased with the increase of CNTs loading. The electrical percolation threshold was found to be between 1 and 2 wt% loading of CNTs.
PETI-330 / MWNT NANOCOMPOSITES COMPOUNDED BY ULTRASONICALLY ASSISTED EXTRUSION
A continuous, commercially viable method for the dispersion of multi walled carbon nanotubes (MWNTs) in polymer matrices using an ultrasonically assisted twin screw extruder has been studied. The effects of ultrasound on die pressure, power consumption, rheological, morphological, mechanical and electrical properties in PETI-330 nanocomposites filled with 0-5 wt. % MWNTs have been evaluated. Ultrasonically treated nanocomposites show increased viscosity with a slight improvement in mechanical properties at various loadings and ultrasonic treatment. An electrical percolation of less than 0.5 wt. % was observed.
A STUDY OF PROCESSING INDUCED PART FAILURES
Of the four pillars required for the successful development of a plastic part; material selection part design processing and service environment processing is often assumed to be the most controllable. Even when the service environment has been properly defined the best design principles implemented and the appropriate material selected seemingly insignificant changes in processing can grossly and adversely affect an otherwise well developed product. This paper will explore case studies where the failure of the part can be traced directly back to improper processing and how shortcomings in processing ultimately predisposed them to premature failure.
A STUDY OF PROCESSING INDUCED PART FAILURES
Of the four pillars required for the successful development of a plastic part; material selection, part design, processing, and service environment, processing is often assumed to be the most controllable. Even when the service environment has been properly defined, the best design principles implemented, and the appropriate material selected, seemingly insignificant changes in processing can grossly and adversely affect an otherwise well developed product. This paper will explore case studies where the failure of the part can be traced directly back to improper processing and how shortcomings in processing ultimately predisposed them to premature failure.
FRACTURE BEHAVIOR STUDY OF MELT COMPOUNDED POLYCARBONATE/ALUMINA NANOCOMPOSITES
Two different molecular weight poly(styrene-maleic anhydride) (SMA) copolymers were used to treat spherical alumina nanoparticles to facilitate dispersion.The treated nanoparticles were then melt compounded with polycarbonate (PC) using a high intensity thermokinetic mixer. It was found that the low molecular weight polymer coating resulted in well dispersed nanoparticles in the nanocomposites with fairly high light transmittance. Furthermore the addition of the spherical nanoparticles improved the impact strength during brittle fracture of the resultant nanocomposites through the formation of multilevel microcracks and microcrazes induced by the nanoparticles.
EFFECT OF CONFINEMENT ON THE MECHANICAL PROPERTIES OF POLYETHYLENE OXIDE IN NANOLAYERED FILMS
Coextrusion through a series of layer multiplying elements has enabled the production of films containing tens to thousands of layers with individual layer thicknesses down to the nanoscale. Dynamic mechanical properties of nanolayered films of polyethylene oxide (PEO) against ethylene-co-acrylic acid (EAA), with layer thicknesses ranging from microns to 45 nm, were investigated. Although crystallinity and layer composition were constant, the glass transition intensity of the PEO was found to decrease dramatically with layer thickness. The application of a combined standard linear solid and the Takayanagi model suggest morphological changes, not decreased mobility of the polymer chains, are responsible.
GREEN LAMINATE COMPOSITES BASED ON POLYPROPYLENE (PP) AND FLAX FIBER
As the demand of green materials and green products are growing, the use of renewable resources and recycle materials are of great attraction. Natural fiber composites have been extensively studied during the last ten years. However, the main focuses were laminate thermoset composites and extrusion/injection composite products. New approach in fabricating thermoplastic composite parts and composite formulation with flax fiber at low cost has been developed to reduce energy consumption and improve the mechanical performance. The laminate composites were prepared by compression moulding. The results demonstrate that the formulation and the fiber treatment play important roles to the performances of the composites.
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