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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Development and Characterization of Thermoplastic Biodegradable Nanocomposites
Biodegradable blends of amorphous Poly(lactic acid) (PLA) and polycaprolactone (PCL) have been developed by melt blending. The morphology of these materials was characterized by means of WAXD and TEM, showing that silicate layers of the kaolinite (chemically modified kaolinite) were intercalated and evenly distributed within the biodegradable matrix. Mechanical, thermal and gas barrier properties of the different blends and nanocomposites were studied and the effect of clay addition on the above-mentioned properties was evaluated.
The Effect of Blending LLDPE Comonomers with Conventional LDPE on the Thermal and Mechanical Properties of Packaging Films
The selection of the correct blend of LLDPE with conventional LDPE is critical when a specific performance property, such as heat seal strength, is required for a thin film application. Extruded blown films using different blends of LLDPE and conventional LDPE were produced. Thermal properties and mechanical properties were influenced by the type and percentage of LLDPE used.
Monitoring Surface Quality of Recycled UPVC Extrudate
Surface quality of profile extruded from recycled uPVC has been examined using a novel on-line visualization system and surface interferometry. A calibrated strip profile was extruded from various grades of recycled uPVC window frame. Surface defects were monitored using a high-frequency line-scan camera and categorised in terms of size, shape and position. Surface roughness was measured using a white light interferometer. PVC recovery method, batch variation and processing conditions were found to affect surface quality of the extrudate.
Rheometric Properties Based Model for an Improved Solid Contents CIM Feedstock
A new formulation for Ceramic Injection Molding (CIM), based on a high-grade alumina powder bound with a water debinding system, composed by a mixture of a low molecular weight polyethylene and a polyethylene glycol, has been developed.The present paper reports the determination of the critical powder concentration of the developed feedstock by rheological model fitting. Semiempirical models were discriminated in order to establish the optimum ceramic powder concentration window.
Injection Molding Variants: A Designer’S Review
The possibilities of plastics processing techniques based on injection molding are continuously expanding. For design engineers it is interesting but time consuming to stay up to date. A systematic approach is presented to classify existing and emerging technologies with respect to product requirements, to take the best advantage of new design opportunities.
Insights into Thermoset Behavior: John Gillham in Retrospect
John Gillham’s work in thermosetting polymers provided a paradigm for the time-temperature transformation characterization of these materials that is now the lens through which we look at their processing. I provide a retrospective and prospective for the insights provided by Gillham into thermoset behavior.
Volume Recovery and the Tau-Effective Paradox
Volume recovery experiments on polystyrene and on an epoxy glass have been made. The experiments on the polystyrene involved novel temperature perturbations which allowed us to obtain the relaxation time as a function of volume during aging. The experiments on the epoxy were performed to investigate the ?-effective paradox. Both sets of experiments indicate that the relaxation time does not depend on the instantaneous volume as assumed in models of structural recovery.
The Rotational Moulding Characteristics of Biodegradable Copolyesters
Biodegradable copolyesters are processed primarily through extrusion and injection moulding. This paper presents preliminary investigations into the grinding and rotational moulding characteristics of commercially available biodegradable copolyester. Cryogenic grinding and subsequent rotational moulding experiments on the copolyester resin resulted in complete mouldings of uniform wall thickness being produced. It was observed that peak internal mould air temperatures of approximately 150 degC are required in order to produce acceptable mouldings.
A New Pressurizable Dilatometer for Measuring Bulk Modulus of Thermosets
A new pressurizable dilatometer has been developed to measure the time-dependent bulk modulus of thermosets during cure. The bulk modulus is important because its magnitude is directly related to isotropic residual stress development in curing thermoset-reinforced composites. The instrument is described and initial calibration runs are shown.
Future Plastics Education
A vision is presented on both future education in plastics and education in future plastics, for the Bachelor’s and Master’s curricula of Industrial Design Engineering. The contributions of recent curriculum adjustments and miscellaneous e-learning activities to the students’ enhanced expertise in designing with plastics are evaluated.
The Use of Beta Nucleation to Produce Microvoided Oriented Polypropylene Films
A unique masterbatch containing a beta nucleating agent was used to produce extruded polypropylene sheet containing high levels of beta phase crystallinity. When these sheets were stretched they became white/opaque in appearance, and had reduced density due to the development of microvoids during the stretching process. Films made from an ethylene-propylene impact copolymer (ICP) exhibited a greater density reduction and had higher opacity than that of comparable films made from polypropylene homopolymer.
The Thermal and Mechanical Performance of uPVC/Styrenic Copolymer Blends
uPVC profiles laminated with woodgrain foils occasionally deform in direct sunlight due to solar energy gain. Blending ASA copolymer and ABS copolymer resins with uPVC increased the heat deflection temperature of the uPVC, therefore reducing the potential for deformation. This paper reports on the thermal and mechanical performance of these blends.
Mechanical Properties and Morphologies of PET-Based Ternary Composites
PET based ternary composites were prepared by using twin screw extrusion technique with the addition of both elastomer and glass fiber. Effects of content of both elastomer and glass fiber were studied on mechanical properties and morphologies of the composites. Impact strength of ternary composites increased significantly after 30% elastomer. SEM micrographs were taken for morphology. SEM analyses showed that there was a good adhesion between fibers and matrix, and adhesion increased with elastomer concentration.
Preparation and Characterization of Nylon 6 Based Conductive Composites
Carbon black filled nylon 6 composites were prepared by two different methods, namely masterbatch dilution technique and melt mixing method. Composites were compared in terms of electrical, mechanical and morphological properties. Electrical resistivity of diluted masterbatch composites was reduced to 10-7 ohm.cm at 1 wt.% of carbon black composition. Tensile strength, modulus, elongation at break and impact strength properties of composites were also studied.
Melt Temperature Field Measurement in Single Screw Extrusion: Influence of Melt Pressure and Die Geometry
Melt temperature fields have been measured in single screw extrusion using novel thermocouple grid, ultrasound and infra-red sensor techniques. The effect of die geometry on melt temperature profile has been investigated using simple slit and rod dies on a single screw extruder. Die geometry of the simple dies studied here was found to have a minor effect on melt temperature field in regions near to the die wall. Die head pressure had a more significant effect on melt temperature distribution.
UV Curable Coatings for Automotive Lighting
In the last few years, UV curable coatings have gained great interest among numerous automotive OEMs and finishers because it allows for more efficient manufacturing, improved performance properties and an overall more environmentally friendly process. In consideration of this interest, the automotive lighting sector should be evaluated as a benchmark for early UV technology success as well as continued innovation in terms of appearance, performance and processing advantages.
Troubleshooting the Ultrasonic Welding Process: The Interpretation of Welding Graphs in a Thermoplastic Plunge Welding Process
This paper will explain the intricacies of interpreting the graphs of the ultrasonic welding graphs. Further, it seeks to explain how these graphs can be used to optimize welding results, troubleshoot welding difficulties and document the process for future use.
Compounding of Conductive Polypropylene/Graphite Composites
Polypropylene (PP) and Natural Graphite Flake (NGF) composites were prepared by three methods using a high-speed thermo-kinetic mixer. The electrical conductivity of the materials was measured as a function of NGF content. Mechanical and rheological properties were characterized to assess the composite's potential to be processed for applications such as fuel cells.
Environmental Stress Cracking – Examples from the Automotive Indsutry
Four case studies are presented to illustrate environmental stress cracking (ESC) within automotive components. ESC is a very important mode of plastic component failure. The presented cases illustrate how the failure analysis process was used to identify the failure mechanism as well as the primary factors responsible for the failures. The four cases depict representative automotive failures involving varied designs and service conditions.
Injection Velocity Control in Plastic Injection Molding
Injection velocity is a difficult process to control due to its complexity and nonlinearity. Different dynamic characteristics with variations in melt temperatures and materials occur. A control strategy using simplified predictive control (SPC) was developed and implemented for injection velocity having wide ranging multiple velocity profiles. The experiment results have shown that the SPC control of injection velocity has good setpoint tracking performance.
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