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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THE POTENTIAL OF NANO-STRUCTURED FILLER MATERIALS TO IMPROVE THE STIFFNESS/TOUGHNESS BALANCE OF PA 6
While developing new polymers, a high level of stiff and simultaneously tough material behavior is an important goal. This study shows a novel approach to optimize the stiffness/toughness behavior of polyamide 6 (PA 6) by incorporating nano-structured filler materials. For stiffness enhancement of PA 6, an organic modified clay material was used. To compensate for the toughness properties, a nano-structured polyamide 6/polyether block copolymer was used. Following an analysis and optimization of the binary material systems, the knowledge was transferred to develop a ternary material system.
REVISIT YOUR EXISTING PARTS ƒ?? FLOW SIMULATION MAY OFFER SIGNIFICANT COST SAVINGS THAT ARE LURKING BENEATH THE SURFACE
The part cost is one of the most important factors when designing a plastic part. However, there have been many-many parts designed over the years that do not follow fundamental plastic design rules. Parts designed without proper knowledge about plastic design principles, eventually affects the part performance and cost. Not only does the part become costly, but the manufacturing cost also increases significantly. This paper presents an example how a flow simulation helped optimize the design of a part and resulted in significant improvement in performance and reduction in part cost.
MODELLING OF THE AGEING PROCESS ON THERMOPLASTIC SURFACES AFTER TREATMENT WITH AN ATMOSPHERIC-PRESSURE PLASMA
After treatment with an atmospheric-pressure plasma, thermoplastic surfaces exhibit marked aging phenomena. These become apparent as changes in the surface properties over time. Although these effects are adequately documented in literature, no generally functional relationship yet exists to describe them. Therefore this study was undertaken. Various thermoplastics were treated with an atmospheric-pressure plasma and subsequently kept under constant conditions. At defined intervals, the surface energy was determined with test fluids on the substrate surface. Taking mass transfer mechanisms into account, an initial approach is then described for modelling these thermoplastic surface properties vs. time following treatment with an atmospheric-pressure plasma.
PREPARATION OF A UV-CURED, UV-ABSORBING COATING
Creating UV-cured coating containing UV-absorbing materials is akin to getting a suntan while wearing sunscreen. Despite this contradiction, we did just that. Motivated by concerns over CO2 emissions and economics, we sought to replace a solvent-based, UV-absorbing coating with an equivalent UV-cured formulation. This was ultimately achieved through creative formulation efforts. Besides being solvent-free and non-flammable, the coating is processed with equipment having a significantly smaller footprint than the older equipment. An additional, unexpected benefit of the new formulation was that the viscosity was significantly lower. This allowed for a significant reduction in coat weight, further reducing the overall costs.
MANUFACTURABILITY STUDY OF NANO-ENHANCED FIBER REINFORCED POLYMERIC COMPOSITES (FRPC)
One of the most environmentally friendly energy generation methods is wind power. In order to compete favorably with the cost of traditional energy generation methods, the wingspan needs to increase from current dimensions. For this to occur, taking advantage of new material developments in nano-reinforced composites is essential. The use nanoparticles have shown improvement in mechanical properties of FRPC. Understanding the manufacturability of these processes is critical, especially during VARTM. Understanding the factors affecting the flow through porous media and the inherent material properties, such as permeability and viscosity, of these nano-enhanced FPRC was the objective herein.
THERMOFORMABLE BRIGHT FILM FOR TPO APPLICATIONS
Thermoformable Fluorex Bright Film was developed to emulate the appearance of plated chrome. However, unlike plated chrome, Bright Film is flexible and thermoformable and can be applied to TPO. The film technology is environmentally friendly and cost-effective, and it has practical applications in various manufacturing processes, such as insert injection molding, thick-sheet thermoforming and extrusion lamination processes. Backed by successful weathering and other testing results, Bright Film has been accepted by the marketplace to accommodate or replace chrome plating as a decorative material for both interior and exterior finishes in the automotive and other industries.
ANALYSIS OF MORPHOLOGY ON INJECTION MOLDED POLY (?æ-CAPROLACTONE) TISSUE ENGINEERING SCAFFOLDS
PCL/NaCl and PCL/PEO/NaCl were injection molded. The water soluble, sacrificial polymer, PEO, and NaCl particulates in the blend were leached by deionized water to produce porous and interconnected microstructure. The effect of leaching time on porous morphology and porosity was investigated. Results showed that PCL/NaCl blend composites had a relatively slow leaching rate due to a lack of connectivity between NaCl particulates. For PCL/PEO/NaCl blend composites, most of the PEO and NaCl particulates can be removed in a short time. This is because the leached PEO domains provide interconnected channels that allow water to reach and leach embedded NaCl particulates.
DEVELOPMENT OF COMPOSITE PIPES FOR RISER APPLICATION IN DEEP WATER
This work deals with the development of composite pipes for riser application in deep water. Initially, an epoxy resin system was toughened by rubber CTBN addition (10 wt%) as a way of improving the flexibility of future risers. Mechanical and thermal analyses were carried out for characterizing the polymeric systems. The influence of matrix toughening and the number of composite layers on the mechanical behavior of the tubes were studied using hydrostatic and split-disk tests. In both tests, the results indicate that the matrix plays an important role in composite fracture processes
THE USE OF PRESSURIZED WATER PELLETS AND SUPERCRITICAL NITROGEN IN INJECTION MOLDING
In injection molding, cycle time, and warpage are critical factors for process economics and product quality. This work focuses on reducing cycle time, and warpage by utilizing water containing polymer pellets. Pellets were prepared by compounding a water carrier particle via extrusion, followed by a batch pressurizing process at a controlled pressure and temperature. Water containing polymer pellets were molded with and without supercritical nitrogen to further decrease the cycle time and minimize warpage. Preliminary results showed that the cycle time and part warpage could be reduced without a major effect on the mechanical properties.
FEM PARAMETRIC STUDY ON EFFECT OF CONSTITUTIVE BEHAVIOR ON SCRATCH VISIBILITY RESISTANCE OF POLYMERS
Three-dimensional finite element method (FEM) parametric study was performed to investigate the effect of asymmetric constitutive behavior on scratch visibility resistance of polymers. The scratch depth and shoulder height of the groove formed during the scratch, which is related to the scratch visibility resistance of polymers, is simulated by considering different asymmetric constitutive behaviors. The simulation results indicate that compressive behavior dominates the scratch visibility resistance of a polymer. Implication of the present findings for designing scratch resistant polymers is discussed.
MAINTAINING A STABLE ENGINEERED NANO-COMPOSITES PROCESS THROUGH MATERIAL CHARACTERIZATION
There is excitement regarding the application of nanomaterials (NMs) in composites. The use of carbon nanotubes (CTNs), nanoparticles (NPs), or other NMs in composite epoxy materials increase strength and elasticity, and reduce the weight of the end product. Nano Composite Epoxy materials will introduce new and unique composite characteristics for industry and consumers. Characterizing NMs during their composite processing is quite different than characterizing previous bulk composite additives. There are additional concerns and characteristics to be aware of with NMs. This paper is an overview of nanomaterial characterization needed to ensure a stable nano-composite epoxy process from beginning to end.
MULTI-LAYER BLOWN FILMS FOR THERMOFORMED FOOD PACKAGING APPLICATIONS
Polyethylene and nylon are used in thermo-formable, multilayer films for food packaging. Through this study, we have developed film structures with up to 30% less nylon and equivalent or better oxygen and moisture barriers than a commercial pizza packaging film structure. These structures exhibited good thermoforming behavior at several draw ratios. We have applied three thermoform-ability indices for the assessment of a filmƒ??s thermoform-ability in this study. One of them was the dimensional thermoform-ability index reported by NOVA Chemicals Corp. The combination of all three indices provides rapid and accurate assessment of the thermoform-ability of film structures.
MONOLAYER AND MULTILAYER POLYOLEFIN FILMS INCORPORATING POLYMERIC MICROSPHERES
Monolayer and multilayer high density polyethylene (HDPE) and polypropylene (PP) blown and cast films were processed with 1.6%, 2.4% and 3.3% microspheres by weight. The films were analyzed for density, tensile properties and tear strength. The multilayer blown films for both polyolefins showed the most decrease in density with the highest loading of microspheres. The monolayer and multilayer HDPE films showed a significant increase in Young's modulus with low loadings of microspheres for both cast and blown films while the PP values decreased for all microsphere films.
STUDY ON THE DEGRADATION RATE OF POLYANHYDRIDE (POLY(SEBACIC ACID), DIACETOXY TERMINATED, PSADT) FOR POTENTIAL DRUG DELIVERY AND TISSUE ENGINEERING SCAFFOLD APPLICATIONS
The degradation rate of polyanhydride (poly(sebacic acid), diacetoxy terminated) is investigated. PSADT tablets are formed using a compression molding device under three different processing temperatures, then immersed into phosphate buffer saline (PBS) for degradation experiments. The mechanisms of degradation and the degradation rate are characterized by the change in molecular weight, reduction in specimen mass, and decrease of specimen thickness. The surface morphology at different degradation times is observed by scanning electron microscope (SEM). The results show that PSADT exhibits the behavior of surface erosion due to the fact that near zero-order degradation kinetics was observed in its degradation process.
SUPERIOR RESISTANCE TO THERMO-OXIDATIVE AND CHEMICAL DEGRADATION IN POLYAMIDES
DuPont's SHIELD Technology allows polyamide resins to be used at higher temperatures than previously achieved. This technology combines several innovations: a new polymer backbone, polymer modifications and additives to enhance performance. The resistance to thermo-oxidative damage and chemical degradation is superior to standard polyamide resins. Examples of improved performance include: Improved air oven aging - retaining >50% of initial mechanical properties after 1000 hours atC Improved fluid aging resistance - maintaining >75% of its impact strength after 5000 hrs at 150C in hot oil. ƒ?› Improved CaCl2 resistance, resisting cracks three times the number of cycles of standard glass-reinforced nylons
AN EASY METHOD TO MONITOR LACTIDE POLYMERIZATION WITH A BORON FLUORESCENT PROBE
The solvent-free controlled ring-opening polymerization (ROP) of lactide is commercially important. A fluorescent dye, difluoroboron 4-methoxydibenzoylmethane (BF2dbmOMe) is employed to probe lactide bulk ROP by measuring the emission from solidified aliquots at room temperature. During polymerization, the fluorescence of BF2dbmOMe in solid-state aliquots exhibited a systematic shift from yellow to blue, accompanied by a reduction in decay lifetime. The fluorescence color change is sensitive to monomer conversion, not polymer molecular weight. The long-wavelength emission with perceivably longer lifetimes arises from BF2dbmOMe dye aggregates, while the dissolved individual dye molecules are responsible for the blue fluorescence with a shorter lifetime.
STABILIZATION OF POLY(BUTYLENE TEREPHTHALATE) FOR DURABLE APPLICATIONS
PBT is an engineering plastic used in molding applications where protection against demanding temperature or light exposure environments is necessary to retain useful properties. Heat & light stabilization of PBT was assessed under thermal aging or light exposures. PBT specimens were subjected to oven aging for 600 hours. The loss rate of physical properties, melt stability, and changes in discoloration were observed. Hindered phenolic antioxidants and phosphite stabilizers were evaluated, providing improved physical properties and reduced discoloration. PBT was subjected to WOM & outdoor light weathering. Protection was possible with a UV-absorber or combined with a hindered amine light stabilizer.
MULTIFUNCTIONAL NANOPAPER FOR WEAR RESISTANT AND CONDUCTIVE APPLICATIONS
Fiber reinforced polymer composites are used in a wide variety of applications such as aerospace, military, defense, and wind energy industries. In many applications, solid particle erosion damage can be a critical issue. In this study, a novel method of fabricating low-cost nanoparticle thin films or nanopapers for use as a surface protective layer for fiber reinforced polymer composites was developed. Inclusion of these nanopapers through current manufacturing methods has shown increases in solid particle erosion protection of up to 7x. The nanopapers have also shown to increase surface electrical conductivity by as much as 16 orders of magnitude.
SYNTHESIS OF HIGH ION-EXCHANGE NANOPARTICLES BY EMULSION COPOLYMERIZATION OF QUATERNARY ALKYL AMMONIUM MODIFIED SULFONATED STYRENE AND DVB FOR COMPOSITE PEM APPLICATION
High ion-exchange capacity (IEC) crosslinked nanoparticles were synthesized by an emulsion copolymerization of divinylbenzene and sulfonated styrene (SS) for application as the proton conducting phase in composite proton exchange membranes. The effects of the counterion of the sulfonated styrene monomer, the surfactant and the crosslinking on the ability to stabilize the emulsion to high IEC were studied. Water-insoluble nanoparticles with IEC as high as 5.2 meq/g were achieved using sulfonated styrene with a quaternary alkyl ammonium cation, a non-ionic surfactant and a crosslinking agent in the emulsion formulation. Nanoparticles with diameters of 20 160 nm were achieved.
EVALUATION OF PROPERTY-PERFORMANCE RELATIONSHIPS OF POLYURETHANE FOAMS USED IN AUTOMOTIVE SEATING APPLICATIONS
High resiliency polyurethane foams are used to provide superior comfort in automotive seat designs. A modified Voigt viscoelastic model is used to simulate vibrational transmissivity (dynamic comfort) during ride. The model links dynamic comfort to foam parameters of dynamic modulus and damping. The results from the simulations show that low dynamic modulus coupled with high damping gives optimal comfort. The simulation results also confirm that thinner seating negatively affects dynamic comfort. A dynamic oscillatory hysteresis analysis is used to obtain both the dynamic modulus and damping parameter. There was reasonable agreement between experimentally measured and model predicted vibrational transmissivity.
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