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 THE ENVIRONMENTAL pH ON THE CORROSION BIOINHIBITIVE PROPERTIES OF MODIFIED CASSAVA STARCHES
The effect of the environmental pH on the properties of modified cassava starches as corrosion inhibitors of carbon steel, was evaluated. Two species were tested: activated (AS) and carboxymethylated starch (CMS). The species were studied using electrochemical measurements in tap water under neutral and alkaline conditions. It was found that protection provided by these biopolymers is dependent on the acidity of the system. Their efficiency is related to the formation of a chelate between macromolecules and ferrous cations. When lowering the pH, the active groups tend to be protonated, hindering the protection afforded for these biopolymers.
PRODUCING MICROLAYER BLOW MOLDED STRUCTURES USING LAYER MULTIPLICATION AND UNIQUE DIE HEAD TECHNOLOGY
Many polymers are extruded in the blow molding process to produce monolayer and multilayer molded articles. Various types of dies are used today in the blow molding process. Each of these types of dies can be used effectively for many polymers in structures containing up to approximately 6 layers. This paper will discuss technology in which layer multiplication techniques are combined with unique die geometries to produce microlayer blow molded structures with significantly greater numbers of layers.
STUDY OF THERMAL DEGRADATION OF PVC PLASTICIZED FORMULATIONS COSTABILIZED WITH d-SORBITOL AND TRIPHENYL PHOSPHITE
PVC is generally degraded during processing, producing several undesirable effects. In this work, mixtures of calcium and/or zinc stearates and epoxidized soybean oil are used as stabilizers. In addition, to improve overall stability, D-sorbitol or triphenyl phosphite were added as costabilizers. The formulation composition was systematically varied considering the following parameters: a) presence of epoxidized soybean oil, b)CaSt2/ZnSt2 ratio and, c) presence and type of costabilizer. Thermal stability was followed during isothermal heating by determining: a) the accumulation rate of some conjugated polyenes and, b) the changes in the tensile properties.
NEW WOOD FIBER BIOCOMPOSITES BASED ON POLYLACTIDE AND POLYLACTIDE / THERMOPLASTIC STARCH BLENDS
This paper aims at developing natural fiber biocomposites based on biopolymers reinforced with wood fibers obtained from a thermomechanical refining process. Polylactide and polylactide/thermoplastic starch blends were used as matrices. Two PLAs were considered with the purpose to investigate the effect of wood fibers on the crystallinity, and therefore, on mechanical properties of composites. Two grades of thermoplastic starch, different in plasticizer content and nature, were used. TPS content in the PLA/TPS blends was 50%. Moreover, two wood fiber types were selected, a hardwood and a softwood, to state the effect of the fiber type on the biocomposite properties.
REVERSE TEMPERATURE PROFILE RHEOLOGY STUDY OF PHB COPOLYMER WITHIN AN INJECTION MOLDING MACHINE
Rheology measurements are normally conducted using a capillary rheometer. It utilizes a flat temperature profile and is significantly different from actual recommended processing condition. This work studied the rheological behavior of PHB Copolymer within an injection molding machine. Viscosity measurements were made using an in-line capillary rheometer nozzle on a molding machine at shear rates ranging from 100 s-1 to 20000 s-1. The results showed that the viscosity of the material reduces significantly when compared to conventional capillary rheometer. These changes can be attributed to processing conditions such as reverse temperature profile, residence time and shear due to screw plasticization.
RECYCLED POLYMERS FOR SUSTAINABLE SOLUTION IN INFRASTRUCTURE
Use of recycled thermoplastic polymer composites for manufacturing and evaluation of structural products as a sustainable solution is discussed in this paper. Durability (aging) evaluations of those polymers have also been carried out to predict their service life. Specifically, ABS polymers were reinforced with 4%, 7% and 12% fiber volume fractions of bi-directional glass fabric (fabric density: 407 gm/sq. mtr. or 12 oz per sq. yard) and were evaluated. Research results indicate the significant potential of recycled polymer composites for different applications with the use of continuous glass fabrics.
HIGH GAIN LEXAN DIFFUSER FILM FOR LCD DISPLAYS
Driven by increasing demand for advanced optical films for LCD displays, a new generation of micro-lensed diffuser films is introduced. Engineered film topography provides light turning functionality for optimum redirecting of source light, through the LCD panel, towards the viewer. Factors affecting film's ability to redirect light are discussed. A new generation of monolithic Lexan display films having higher luminance gains, is introduced. Performance gains in actual LCD displays are demonstrated, and film making process is reviewed. Up to 10% luminance improvement over standard micro-lensed films was realized, while retaining inherent strength and dimensional stability attributes of monolithic polycarbonate films.
IONOMER MODIFIED ASPHALT
The structure and properties of ionomer modified asphalt were investigated. The thermal properties, morphology and rheology of four concentrations of a Pen grade 64-22 asphalt and the zinc salt of a poly (ethylene-co-methacrylic acid) were studied. After establishing the linear viscoelastic range of response through strain sweep, frequency sweep at a temperature range of 30-80C were conducted to study the dynamic mechanic properties of the modified blends. The ionomer modified and base asphalt samples were subjected to simulated real life conditions such as long and short aging, high and low service temperatures. Better performances were achieved by the modification
SELF FORMATION OF MUCELL FROM PS/POLYANILINE-HALLOYSITE CLAY (PHC) INJECTION MOLDING
In this work, we introduce an alternative approach to microcellular injection molding, which does not require any equipment modifications. We have developed an additive which is compounded with the thermoplastic pellets which are then run in standard injection molding equipment. The additive was produced by an in-situ polymerization of polyaniline into Halloysite-Clay, where the HC is naturally exfoliated because of its tubular shape and uniform surface charge. The PANI has the function of adsorbing both water and CO2 gas. Preliminary results show that cycle time can be decreased without an adverse effect on part dimensional stability and mechanical properties.
RAPID DETERMINATION OF CURE RATE AND DIRECT IDENTIFICATION OF SPATIAL VARIATIONS IN CROSS LINK DENSITY
Traditional bulk thermal analysis provides a sample-averaged result and cannot generally supply sufficient information about complex structures or heterogeneities within polymeric systems. A nanoscale thermal probe heats a localized region on the sample surface to measure its thermal transition temperatures. Transition temperature microscopy (TTM) enables these measurements to be carried out rapidly at a succession of points, thus creating automated high-resolution spatial maps of the thermal properties. We demonstrate how nanoTA can be used to characterize cross link density and to study cure rate in a time resolved manner.
MANUFACTURING OF MICROPELLETS USING RAYLEIGH DISTURBANCES
The goal of this research work is to prove the capability of manufacturing spherical polymer micropellets of a unit size using Rayleigh disturbances. This phenomenon describes the breakup of a liquid stream into droplets while being deformed by another fluid under a competing force field that results from surface tension effects. Here, a polymer melt was surrounded by a jet of hot air in a special nozzle. The main focus of this work is on the design and construction of the micropelletizer and the search for a process window that results in break-up. Micropellets were successfully manufactured.
IDENTIFYING CONTAMINANTS IN PLASTIC PELLETS AND HANDLING SYSTEMS: ANGEL HAIR, SNAKE SKINS, POLYMER FINES, WAXES AND LUBRICANTS
Mechanical processes used to make plastic pellets and transport them through manufacturing, shipping and end-use can create contaminant bodies. These bodies include normal polymer fines, high-melting polymer (angel hair, snake skins), surface applications like lubricants and waxes and oligomers. They cause various problems in material handling, processing and product performance. Analytical laboratory techniques can readily provide the identification needed to specify corrective actions. Examples from polyamide processing are discussed.
IONOMER MODIFIED ASPHALTS
The structure and properties of ionomer modified asphalt were investigated. The thermal properties, morphology and rheology of four concentrations of a Pen grade 64-22 asphalt and the zinc salt of a poly (ethylene-co-methacrylic acid) were studied. After establishing the linear viscoelastic range of response through strain sweep, frequency sweep at a temperature range of 30-80‹?øC were conducted to study the dynamic mechanic properties of the modified blends. The ionomer modified and base asphalt samples were subjected to simulated real life conditions such as long and short aging, high and low service temperatures. Better performances were achieved by the modification.
THE ROLE OF PARTITIONING OF ORGANOCLAY ON MICROFIBRILLAR MORPHOLOGY DEVELOPMENT OF PP/PBT BLEND NANOCOMPOSITE FIBERS
The aim of this work was to provide an insight on the effect of partitioning of organically modified montmorillonite (organoclay) on the droplet deformation and resulting microfibrillar morphology development in melt spun Polypropylene/Poly(butylene terephthalate) /Organoclay blend nanocomposite fibers. The samples with the same blend ratio (80/20) but varying in organoclay content were prepared with and without the compatibilizer by using a melt intercalation process in a co-rotating twin screw extruder. It was demonstrated that presence of nanoclay in multi blend system can play different roles on the extent of microfibrils formation depending on nanoclay partitioning.
EFFECT OF PRESSURE ON CRYSTALLINITY OF INJECTION MOLDED POLYPROPYLENE/ETHYLENE-OCTANE COPOLYMER BLEND:BE DIFFERENT ON CRYSTALLIZATION KINETICS
In this experiment, a different effect of pressure on crystallinity and crystallization kinetics was found compared with anterior research. This experiment is concern with the effect of holding pressure on crystallinity of isotactic polypropylene (iPP) in injection molded polypropylene (PP) /Ethylene Octane Copolymer (POE) blends with fixed weight ratio (75/25). Sliced samples cutting from the midway of the moldings were investigated by differential scanning calorimetry (DSC). Absolute crystallinity of PP of every sample with different depth can be calculated. Crystallinity was found to be decreased with increasing holding pressure although the crystallization kinetics was accelerated.
EXTRUSION OF POLYPROPYLENE AND HYDROCARBON RESIN BLENDS
Hydrocarbon resins (HCR) can be extruded with polypropylene resin (PP) directly from the dry blend to save tolling cost from a masterbatching process.?ÿ Up to 20% of HCR has been successfully extruded using a single screw extruder. The screw design and processing temperatures are critical to avoid surging and to achieve a comparable output rate as PP.?ÿ Barrier screws with Maddock type mixing section were used to compare extrusion performance.?ÿ Internal pressures along the screw were monitored to determine the process bottleneck and to optimize the processing conditions. Extrusion performance is presented at different blend ratios and screw designs.
ESTIMATION OF TEMPERATURE INCREASE IN A PARTIALLY FILLED ZSK-90 COROTATING TWIN-SCREW EXTRUDER USING MESH PARTITIONING TECHNIQUE
The velocity distribution predicted by an isothermal simulation of the flow in a co-rotating twin-screw extruder is used to estimate the heat generated due to viscous dissipation. If the conveying and mixing elements of the extruder are assumed to be fully filled, the predicted temperature increase is much larger than the corresponding experimental values. If the temperature increase is calculated based only upon heat generated in the portion which has positive value of pressure, that is, the portion which is fully filled, the predicted temperature increase matches closely with the corresponding experimental data.
PHYSICAL PROPERTY RETENTION OF EXTERIOR AUTOMOTIVE MOLD-IN-COLOR PLASTICS AFTER UV EXPOSURE
This paper explores the UV weathering performance of Mold-In-Color plastic technologies used for exterior trim applications. The focus is the retention of physical properties after exposure to lab UV radiation that simulates actual outdoor exposure. Various test specimens are exposed to Xenon Arc UV radiation then tested for mechanical properties vs. unexposed controls. Samples are also analyzed for change in color and gloss. Finally the parts are analyzed for surface chemistry changes via infrared spectroscopy and surface morphology. These analysis are correlated with physical property changes
RHEOLOGICAL MORPHOLOGICAL RELATIONSHIP IN IMMISCIBLE AND REACTIVELY COMPATIBILIZED SAN/EPDM BLENDS
In immiscible blend of SAN/EPDM a coarse morphology is formed. In reactive blends, formation of graft at the interface causes fine stable droplet morphology. Favis equation shows at 17 wt% of graft the size of EPDM would be minimum. The interfacial tension of the blends determined by Palierne and Choi-Schowalter models shows minimum value at 1 phr initiator. The droplet morphology is changed to composite in two step blending method. A higher apparent volume fraction of EPDM in the blend with composite morphology which has been also obtained by Kerner equation is an indication of the evolution of composite morphology.
CAUSE OF OCCASIONAL FAILURE OF CPVC PIPES AND FITTINGS IN HYDRONIC HEATING SYSTEMS
Chlorinated polyvinylchloride (CPVC) pipes and fittings are commonly used in hydronic heating systems. However, there are occasional failures of CPVC pipes and fittings used in these systems due to chemical contamination by the lubricant oil used in the heat exchanger refrigerant. Although leaks in the heat exchanger are rare, when a leak does occur, it can lead to almost immediate failure of the CPVC piping system due to chemical attack by the polyol ester (POE) lubricant oil in the refrigerant. This paper discusses the results of our forensic failure analyses on CPVC hydronic piping. Also we present the results of our studies on the chemical compatibility of POE compared to polyvinylether (PVE) refrigerant lubricant oils.
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