SPE Library
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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Conference Proceedings
RELATIONSHIP BETWEEN PROPERTIES, CITRATE CONTENT AND POSTPRODUCTION TIME FOR A PLASTICIZED POLYLACTIC ACID
Due to the recent interest on citrates as a biodegradable plasticizer for Polylactic acid PLA, several PLA blends that were plasticized with tributyl citrate TBC were prepared in a co-rotating twin screw extruder. A range of 12.4 to 22.5% by weight was considered for the plasticizer content. The thermal, rheological and mechanical properties were correlated with the plasticizer content and compared with pure Polylactic acid. Additionally, the change of these properties as a function of postproduction time was studied and correlated with the plasticizer permanence.
IMPROVEMENT IN SURFACE QUALITY OF MICROCELLULAR INJECTION
MOLDED PARTS
Microcellular injection molding has many advantages
such as cost savings reduced cycle times and excellent
shrinkage properties. However surface defects on the
microcellular injection molded parts—such as gas-flow
swirl marks and a lack of smoothness—still remain a
challenge. This paper describes a method to improve the
surface quality of microcellular injection molded parts.
IMPROVEMENT IN SURFACE QUALITY OF MICROCELLULAR INJECTION MOLDED PARTS
Microcellular injection molding has many advantages such as cost savings, reduced cycle times, and excellent shrinkage properties. However, surface defects on the microcellular injection molded partsƒ??such as gas-flow swirl marks and a lack of smoothnessƒ??still remain a challenge. This paper describes a method to improve the surface quality of microcellular injection molded parts.
THERMODYNAMIC ANALYSIS OF SHAPE MEMORY PROPERTIES OF POLYMERS AND NANOCOMPOSITES
The experimental data on shape memory (SM) properties of polyurethanes and their composites of organoclay, carbon nanofiber (CNF), silicon carbide (SiC), and carbon black were qualitatively analyzed using entropy elasticity models. These entropic elasticity models were derived for crystallizable polymer networks, however they were also found suitable for shape memory polymers and nanocomposites. It was revealed that the unbalanced Helmholtz free energy in the absence of adequate crystallinity in composites of CNF and SiC was primarily responsible for reduction of SM properties.
BATCH FOAMING OF GLASS FIBER REINFORCED WOOD PLASTIC COMPOSITES
Foaming of wood plastic composites (WPC), along with the addition of small amounts of glass fiber can improve the mechanical properties of WPC. Such improvements have the potential to help WPC find applications in areas where it has been previously overlooked due to factors such as its low strength and high density when compared with natural wood. The foaming process involves many parameters that interact to determine the quality of the final product. This paper investigates some of these parameters with the aim of optimizing them.
CHARACTERIZATION OF PROPERTIES OF WOOD PLASTIC COMPOSITES (WPC) WITH GLASS FIBER REINFORCEMENTS
The mechanical properties of wood plastic composites (WPC) can be improved with the addition of small amounts of glass fiber. This improvement can help WPC find applications in areas where it has been previously overlooked due to factors such as its lowstrength when compared with natural wood. Mechanical properties such as flexural and impact strength showed improvements upon the addition of glass fibers (GF) in certain compositions. This paper examines the effects of GF upon these properties.
FINITE ELEMENT MODELING AND MICROSTRUCTURE ANALYSIS FOR CONTOUR LASER TRANSMISSION WELDING OF GLASS FIBRE REINFORCED NYLON 6
This paper presents FEM heat transfer analysis and experimental results for contour laser transmission welding of glass fibre reinforced Nylon 6. Predicted temperature fields near the weld interface were compared with the dimensions of the heat affected zone, and weld widths. Temperature profiles at the weldline were also estimated from the modeling data.
STUDY ON THE SHEAR VISCOSITY OF HDPE-WOOD
COMPOSITES/SUPERCRITICAL CO2 SOLUTION
In this work the shear viscosities of wood plastic
composites (WPC)/ supercritical CO2 (sc-CO2) solutions at
different die temperatures and sc-CO2 contents were
measured by a slit die attached on a single-screw extrusion
system. A theoretical model based on the Cross-Yasuda
model and Arrhenius equation was developed to describe
the shear-thinning behavior of the WPC/ sc-CO2 solution.
The model was a function of temperature pressure sc-CO2
content and shear rate.
STUDY ON THE SHEAR VISCOSITY OF HDPE-WOOD COMPOSITES/SUPERCRITICAL CO2 SOLUTION
In this work, the shear viscosities of wood plastic composites (WPC)/ supercritical CO2 (sc-CO2) solutions at different die temperatures and sc-CO2 contents were measured by a slit die attached on a single-screw extrusion system. A theoretical model based on the Cross-Yasuda model and Arrhenius equation was developed to describe the shear-thinning behavior of the WPC/ sc-CO2 solution. The model was a function of temperature, pressure, sc-CO2 content, and shear rate.
VIBRATION WELDING POLYPROPYLENE – EFFECT OF MFI ON WELD STRENGTH AND MICROSTRUCTURE
This paper examines the weld strength and microstructure of three polypropylene homopolymers of different melt flow indices (MFI). The heat affected zone thickness was observed to be inversely proportional to weld pressure and polymer MFI. The weld strength was observed to decrease with pressure. The weld strengths of lower MFI polymers were more weld-pressure sensitive.
VIBRATION WELDING POLYPROPYLENE ƒ?? EFFECT OF MFI ON WELD STRENGTH AND MICROSTRUCTURE
This paper examines the weld strength and microstructure of three polypropylene homopolymers of different melt flow indices (MFI). The heat affected zone thickness was observed to be inversely proportional to weld pressure and polymer MFI. The weld strength was observed to decrease with pressure. The weld strengths of lower MFI polymers were more weld-pressure sensitive.
INVESTIGATION OF COMPARITIVE STRESS DISTRIBUTIONS IN THERMOFORMING VERSUS INJECTION MOLDING
The comparison of stress distributions has been investigated in thermoformed and injection molded parts of a similar design. Injection molding is traditionally preferred for automotive applications because of its ability to create parts with minimal internal stress. However in recent years because of potential cost reductions thermoformed parts are often being substituted. Matrox Inspector has been used to evaluate internal stress created by both processes. Results show a difference in the comparative stress distributions of similar parts that is dependent on location.
THE INFLUENCE OF THE PROCESSING CONDITIONS ON THE PS/MWCNT COMPOSITES PREPARED WITH TWIN SCREW EXTRUDER
Polystyrene/multi-wall carbon nanotube composites, PS/MWCNT, were prepared with co-rotating twin screw extruder. PS/MWCNT was prepared by diluting highly concentrated MWCNT masterbatch chips. We investigated rheological and mechanical properties of PS/MWCNT composites. Rheological and mechanical properties of PS/MWCNT composites depended on concentration of PS/MWCNT and processing conditions such as screw speed, feeding rate.
NATURAL FIBER-PHENOLIC-HANNEBACHITE COMPOSITES: EFFECTS OF FIBER TYPE
The management of greenhouse gasses can certainly benefit from better marshalling of our wooded lands. Therefore, our recent research has focused on developing wood-substitute composites without wood in them from natural fibrous materials, e.g., jute, miscanthus, kenaf, wheat straw, and industrial hemp and plate-like hannebachite crystallites. Imaging, DSC, flexural strength and water sensitivity measurements were undertaken on composites formulated from the aforementioned natural fibers. Comparative effects on the mechanical and thermal properties were ascertained.
3D SIMULATIONS OF A REACTIVE FLOW IN SCREW ELEMENTS OF CLOSELY INTERMESHING TWIN SCREW EXTRUDERS: CONVENTIONAL AND VARIABLE SPEED EXTRUDERS
The peroxide-initiated degradation of polypropylene in conveying screw elements of closely intermeshing twin screw extruders (COITSEs) is analyzed by means of a three-dimensional (3D) simulation approach. The simulations are implemented for a conventional and a special design screw element (from a variable speed extruder). Different values of peroxide concentrations and mass throughputs are implemented to analyze the reactive system of interest in terms of the specified extruder design.
TWIN SCREW EXTRUSION OF THERMOPLASTIC POTATO STARCH
Among starch species, potato tends to have a much narrower processing window in extrusion machinery for the preparation of thermoplastic starch compared to other common starch sources from corn or wheat. The present study demonstrates through a series of screw design refinements, a working approach to setting up a reasonable processing window of this starch type and discusses the issues involved. Finally the paper demonstrates through a series of trials with one of the optimal screw configuration, the influence of shear and formulation on final properties for the thermoplastic product.
THE FOAMABILITY OF POLYPROPYLENE COPOLYMER BLOWN WITH ARGON NITROGEN AND HELIUM
Due to environmental concerns research has been carried out to investigate the feasibility of using inert gases as blowing agents in plastic foaming processes.However the foamability of polypropylene copolymer blown with argon nitrogen and helium has not been reported previously. This paper investigates the nucleating powers of these gases to foam polypropylene copolymer by studying the polymeric foaming processes in situ.
EFFECT OF OMMT CHARACTERISTICS ON SCRATCH DEFORMATION BEHAVIOR OF POLYPROPYLENE TERNARY NANOCOMPOSITES
Compatibilized polypropylene (PP)/organically modified montmorillonite (OMMT) nanocomposites were prepared via melt intercalation. OMMTs with different gallery spacing were chosen. The effect of OMMT structure on scratch deformation behavior was investigated.Correlations between scratch deformation parameters with mechanical, thermal and melt flow behavior of the nanocomposites were established and discussed.
THE EFFECT OF ANNEALING ON DEFORMATION AND FRACTURE BEHAVIOR OF INJECTION MOLDED PLA
The effect of annealing on the deformation and fracture behavior of injection molded Poly (lactic acid) (PLA) was investigated. The behavior of as-molded amorphous PLA was changed from brittle to ductile by annealing above Tg (60?øC) for 5 min. On the other hand, the sample annealed above Tcr (re-crystallization temperature) showed brittle fracture.
MECHANICAL PROPERTIES OF SYNTACTIC FOAMS
Syntactic foams on epoxy and on vinyl esters were produced and tested. Different types of glass microballoons were used. Samples were tested on compression tension bending fracture toughness and on impact resistance. The influence of the type of microballoons their concentration and the type of polymer matrix properties was studied. Density and morphology studies were used for the control of technology. Results of experiments are compared with different theoretical models used for the properties prediction.
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