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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MICROCELLULAR INJECTION MOLDING OF POLYLACTIDE WITH TALC
The effects of talc content and injection flow rate on the foaming behavior of injection-molded microcellular polylactide (PLA) were investigated. Cell morphology with a cell size of less than 20 µm and cell density of greater than 108 cells/cm3 was successfully produced. The addition of 5 wt % talc to PLA increased the cell density roughly ten times and decreased the cell size about three times. Also, higher injection flow rate resulted in finer cells with greater density.
TROUBLESHOOTING RATE LIMITATIONS FOR MELT-FED SINGLE-SCREW EXTRUDERS
Compounding lines that utilize single-screw extruders as the pumping device for pelletization can be severely rate limited if the metering channel of the single-screw machine is not optimized for the process. This paper provides the troubleshooting methodology for solving this type of problem using a case study.
CASE STUDIES OF NEW APPLICATION DEVELOPMENT USING ELECTRON BEAM IRRADIATION
Developing new cost-effective polymer products is challenging in the current competitive marketplace. Electron beam irradiation is a powerful tool used to improve the properties of a wide range of materials, particularly polymers, and has been used to gain a competitive advantage in many successful commercial products. This paper reviews three case studies in the development of new polymer products using electron beam irradiation and the role of the electron beam processor.
IN SITU OBSERVATION OF THE FOAMING PROCESSES OF CELLULOSE NANOFIBER REINFORCED POLYLACTIC ACID BIOCOMPOSITES
This paper examines the effect of fiber content on the foaming behavior of cellulose nanofiber reinforced polylactic acid biocomposites. The in situ observation of batch foaming processes was conducted by using a high-speed camera. It was found that nanofiber content has a significant effect on the cell nucleation and growth in the composite foams. As the fiber content increased, the cell nucleating power increased and cell growth rate decreased.
ECONOMIC BENEFITS OF CROSSLINKABLE POLYAMIDES – A LOOK AT ELECTRON BEAM IRRADIATED MOLDED PARTS
A new family of radiation-crosslinkable polyamides has been developed for the North American market. A key component in the offering is technical support for product development. Companies can crosslink the polyamide using their current equipment or that of a contract electron beam processor and replace higher cost thermoplastic resins with the radiation crosslinkable polyamide. This paper discusses the technical advantages and target applications of the radiation crosslinkable polyamide.
SYNTHESIS OF POLYHEDRAL OLIGOMERIC SILSESQUIOXANE (POSS) FUNCTIONALIZED CARBON NANOTUBES
Polyhedral oligomeric silsesquioxane (POSS) was covalently attached to modified carbon nanotube (CNT) surfaces to improve nanotube dispersion. Two types of POSS were attached to multiwall CNTs. TGA, ATR-FTIR and TEM characterization of the CNT-g-POSS hybrids demonstrated covalent bonding of POSS to the CNT surface. POSS- modified CNTs showed homogeneous, stable dispersion in THF.
THE SCIENCE OF FORMULATING OLEFIN BLOCK COPOLYMERS
Introduced in 2006, INFUSE™ Olefin Block Copolymers (OBCs) have since been explored in many markets and application areas, including soft compounds. Key molecular design elements were identified as critical factors to the manufacturing of thermoplastic elastomers (TPE) with the required property balance. This paper is aimed at providing an overview of the main considerations for formulating OBCs for soft compound applications and highlights the sustainability advantage of OBC compounds relative to styrenic block copolymer compounds.
EVALUATION OF LONG-TERM PERFORMANCE ON COMPOSITE PIPES
The creep fracture of pipes is evaluated by the applied internal pressure. However, there were some disadvantages such as long testing time, large equipment and careful treatment on the stress rupture test. In this study, the new creep testing method which is simple and accelerated testing was proposed on composite pipes such as multilayer pipes. The results of the fluctuating internal pressure test on multilayer pipes were also described.
SOLUBILITY AND DIFFUSIVITY OF CARBON DIOXIDE IN POLYPROPYLENE/MICRO-CALCIUM CARBONATE COMPOSITES
This work aimed to investigate the effect of concentration of micro level filler, i.e. micro- calcium carbonate (MicroCaCO3) and interface bonding condition between filler and polymer matrix on solubility and diffusivity of CO2 in polypropylene (PP)/MicroCaCO3 composites. The diffusion coefficient of CO2 decreased with increasing loading of MicroCaCO3 for both kinds of PP composites, suggesting that MicroCaCO3 acted as significant gas barrier during gas diffusion in PP composites.
STUDY OF THE KINETIC OF SLIP AGENT MIGRATION IN POLYETHYLENE SHEETS
Line speeds in vertical form fill seal machine can be greatly increase by using slip agents such as erucamide. The focus of this research was to develop a tool to rapidly characterise the amount of slip agent in a polyethylene film sample. Using a Fourier Transform Infrared spectrometer, a model of the kinetic of erucamide migration in polyethylene film was developed. This model can further be used to determine one’s erucamide content of a sample polyethylene film.
EVALUATION OF LONG-TERM PERFORMANCE ON PLASTIC PIPES FOR HOT WATER SUPPLY
Crosslinked polyethylene (PEX) pipes and multilayer pipes of PEX and ethylene-vinyl alcohol copolymer (EVOH) as a high oxygen barrier are used for hot water pipes. The long-term performance of them was evaluated in hot water and air. It was found that the yield stress of PEX and multilayer pipes increased with elapsed time due to crystallization. It was also found that multilayer pipes had a blister at the interface between PEX and EVOH.
NANOFIBRILLATED CELLULOSE REINFORCED POLYVINYL ALCOHOL: PROPERTIES AND SOLUBILITY OF CARBON DIOXIDE
Polyvinyl alcohol (PVOH) was mixed with a nanofibrillated cellulose (NFC) fiber suspension in water followed by casting. The transmission electron scanning (TEM) images revealed that the NFC fibers dispersed well in PVOH. The presence of NFC significantly increased the tensile modulus of the nanocomposites nearly threefold and could serve as a nucleating agent, promoting the early onset of crystallization. However, at a higher NFC content, it led to greater thermal degradation of the PVOH matrix.
EXTRUSION FOAMING BEHAVIOR OF PET
The extrusion foaming behavior of polyethylene terephthalate (PET) with CO2 was evaluated. The foaming morphologies of PET/nanocomposites and PET/chain extenders were also assessed. The foamed extrudates were analyzed for expansion ratio, cell structure, and degree of crystallinity using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Finally, the effect of the die temperature on the cell structure of the PET foam samples was studied.
SCREEN PRINTING PVC FILM WITH UV INK
This study’s purpose was to develop a process for screen printing PVC film with UV-curing ink. PVC film is made with plasticizers that migrate to the surface and reduce ink adhesion. Surface treatments and ink additives were investigated. The study showed for recently manufactured film, poor ink adhesion was a result of incomplete cure. The ink’s high pigment loading impeded penetration of UV radiation. Dilution of the pigment with clear base enabled complete cure
CREEP FAILURE OF A POLYACETAL HOSE CLAMP
A plastic ratchet-type hose clamp had failed catastrophically while in service, causing water damage. The investigation revealed that the cracking occurred within a relatively short period of time due to creep rupture. Additional testing was performed to substantiate the cause of failure. This paper will focus on the steps used to characterize the mode of failure, and how accelerated testing methods were utilized to predict the life of the part.
FOAMING BEHAVIOR OF MELT COMPOUNDED THERMOPLASTIC POLYURETHANE IN PRESENCE OF BUTANE
The hard segments in thermoplastic polyurethanes (TPUs) are statistically distributed in the soft matrix phase. This distribution can be changed by processing the TPU material at various conditions such as melt processing or isothermal treatments. Furthermore, the hard segments contribute to the microcrystalline phase in TPUs. In this study, the foaming behaviour of “as received” and “processed” TPUs has been investigated using n-butane as a blowing agent.
EFFECTS OF PHYSICAL SURFACE TREATMENT ON METAL SURFACE MORPHOLOGY AND MECHANICAL PROPERTIES OF METAL INSERT INJECTION MOLDINGS
This study is to clarify the adhesion mechanism as target. Various surface treatments on the metal were carried out to investigate its effect on the adhesion property of insert moldings. It is found that the surface roughness of metal could be changed by the chemical agent with different ratio of nitric hydrofluoric acid and immersion time. Optimum surface treatment exists to obtain high adhesion property between polymer and metal.
NEW POLYCARBONATE COMPOSITIONS WITH LOW OSU HEAT RELEASE & SMOKE VALUES FOR AIRCRAFT APPLICATIONS
New polycarbonate blends afford the first UV stable resins with low color, low smoke and low OSU Heat Release values (< 65/65). In addition, the resins can be prepared with good melt flow and excellent ductility. The excellent colorability and UV stability, combined with the compliance to the FAA/OEMs fire, smoke and toxicity regulations, allows for the fabrication of interior opaque components such as interior aircraft windows frames, seat parts, grilles and personal service units.
EVALUATING FRACTURE TOUGHNESS IN DEGRADED POLYMERIC THIN FILMS
Thin polymer films are under consideration as materials for use in roof top mounted solar thermal collectors. The fracture behavior of these materials is of particular concern for this application. When exposed to UV light, film degradation can lead to reduced fracture toughness. In this paper, a method for evaluating the fracture behavior of thin films as a function of the extent of degradation is described. Pilot study results for fracture behavior of polyethylene film are presented.
EFFECT OF D-LACTIDE CONTENT ON THERMAL BEHAVIOR OF POLYLACTIDE IN PRESENCE OF CO2 DISSOLVED GAS
In this study, the effect of dissolved CO2 on the thermal behavior of PLA with various D-contents (with and without talc) has been investigated during the cooling process at atmospheric pressure in a regular differential scanning calorimeter (DSC) and a high-pressure DSC. The results show that the crystallinity of PLA samples improves by increasing the CO2 pressure, reducing the D-content, and adding talc. Also, Tg and Tm shift to lower temperatures as the pressure increases, due to the plasticization effect of CO 2.
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