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.
Differences in solids conveying, screw pressure profile generation, output and melt temperature varies between single piece barrel with integral feedport design and two piece water cooled feedblock and barrel designs. Two different resins will be studied using the same screw design for each barrel configuration.
Application of Raman spectroscopy to obtain crystallinity data, on-line, during fiber spininning of polypropylene polymers is described. These data were obtained to develop validated fundamental fiber spinning models. These validated fiber spinning models will be used to guide fiber spinning for rapid product development.
Plastics engineers are very aware of the use of polymeric materials in the medical field but little is known about a technically interesting and rapidly growing application that is totally dependent on polymers, biopharmaceutical manufacturing. Since 1990, producers have been replacing their traditional stainless steel tanks and pipes in both new construction and retrofit situations with sterile pre-engineered single use plastic bags equipped with the necessary inlet and outlet ports, tubing, filters, valves, and manifolds.
CAE injection molding simulation software combined with birefringence analysis was used for resolving stress cracks and non-uniform stress distribution on an injection molded part. The part with a two-pin gate runner system was molded and cracked after molding. The birefringence showed high stresses on the part, which was in good agreement with part cracks. Based on the recommendation of the injection molding simulation, the part cracks were resolved by optimized gate location and runner system design. The birefringence shows low stresses on the final injection molded part.
Rotational molding is virtually a shear and pressure free process. The number of materials suitable for rotational molding is limited. This paper gives a summary of a fundamental study on newly developed low viscosity metallocene catalyzed PP resin for rotational molding applications. The influence of viscosity, surface tension and thermal properties on the sintering behavior of the polymers was investigated. Rotational molding experiments were carried out and mechanical properties of the molded parts were characterized.
It is known that bulk or average density is the major parameter controlling the mechanical properties of polymer foams. Nevertheless, density profile has also a major impact especially for structural foams where an unfoamed skin is enclosing a foamed core. In this study, the effect of density profile on the flexural modulus of a structural foam is discussed in terms of skin thickness and taking into account the local variation of density (related to void fraction) with position.
Experimental data and three-dimensional finite element simulations of the flow in two different profile dies for glass run seal of a car are presented. The flow in one of the two dies, a plate die, is found to be highly unbalanced. Using a feeder plate in the second die (a stepped die configuration) the flow at the exit of the die was properly balanced.
There continues to be a strong demand for chrome-plated plastic parts in exterior and interior automotive components. In this paper, we present two new PC/ABS products suitable for use in these applications. A high-heat product is designed to meet the growing need for improved heat stability, impact and flow in addition to good plate adhesion. A medium-heat product is designed for improved flow, impact and excellent plate adhesion. Effects of key material variables on processing and plating performance are examined.
The subject of uncertainty of measurement in spectrophotometric measurements of the color of plastics is reviewed. Definitions of the components of uncertainty are offered, and methods of assessment and calculation of the components of uncertainty are revealed so that the user might prepare an uncertainty budget for one's own measurement system. The practical applications of total measurement system uncertainty in industrial applications are addressed. Finally, example data sets are presented from measurements of several colored plastic materials
Gaps in weld seams are an obstacle for applying the contour welding strategy in laser transmission welding of polymers. This paper examines the effect of laser (power) and material (carbon black level) and geometric (gap thickness) parameters on the shear strength of PA6 lap welds. Assemblies were made using a continuous wave diode laser in a contour welding mode.
It is well known that in the extrusion coating process, peel strength to aluminum foil and other non-porous substrates decreases with decreasing coating thickness. The peel strength is found to be more sensitive to changes in thickness as the adhesion between the coating and substrate improves. An analysis of the peel test shows that changes in the critical dimension of the deformation region at the peel front may be responsible.
Impact modified Polycarbonate blends are preferred for medical housings due to their excellent balance of mechanical properties, flame resistance and processability. These housings are increasingly subject to aggressive cleaners and disinfectants to meet heightened sanitation requirements. New flame retardant polycarbonate blends using tailored silicone copolymers exhibit improved environmental stress cracking resistance (ESCR) to many classes of these cleaners.
Sensitivity of the melting profile to the screw temperature in a single-screw, plasticating extruder was analyzed using a three-dimensional finite element simulation of the melting process. Numerical predictions are compared with the corresponding experimental data from screw freezing experiments. Against the conventional intuition, the predicted melting rate in the compression section of the extruder was found to decrease with increasing screw temperature.
Two designs of tube tooling with different draw down ratios were analyzed using a multi-mode viscoelastic flow model to reduce the post-extrusion shrinkage in a cable jacketing process with polyvinylidene diflouride (PVDF). The analysis focused on reducing both elongation and hoop stresses, which were believed to correlate most closely with the shrinkage. Results showed both elongation and hoop stresses were reduced. Cable tensile tests were conducted to compare with the numerical findings.
Two routes for purification of shrimp shells to obtain chitin whiskers were evaluated. The best result was found when demineralization was performed with 1M HCL followed by sample deproteinization with 5% w/v KOH. In order to obtain chitin whiskers an acidic hydrolysis was performed with several acids: HCL, H2SO4 and H3PO4. Chitin whiskers with lengths between 90 and 170 nm were obtained with phosphoric acid. The process was evaluated by FTIR, TGA and TEM.
A pressure rheometer was built to measure rheological properties of polymers at elevated pressures and temperatures. However the viscosity at high deformation rates decreases more than the predicted theoretical value represented by the Cross-WLF model. This paper studies the role of viscous heating in the resulting viscosity deviations by means of simulation using the Radial Functions Method (RFM).
The cost of solar collectors can be reduced by using polymeric glazing and absorber materials, but the durability of their optical and mechanical properties must be demonstrated. Polycarbonate glazings with ultraviolet screening layers have been shown to survive accelerated light intensity for an equivalent 20 years outdoor exposure in Miami, FL. The mechanical properties of two candidate absorber materials—metallocene-based multi-density polyethylene and polypropylene—have been measured as a function of wet and dry thermal exposure.
Paper identifies experimentally the process conditions leading to specimen surface damage of laser-transparent polycarbonate during laser transmission welding. Influence of surface finish, defects and contamination is determined. Surface damage mechanisms are discussed. The surface damage threshold (SDT) is measured over a range of laser speeds and powers. Suggestions are provided for increasing the SDT.
Fiber jamming is perhaps the least understood defect in molding of polymer composites. This paper presents a dimensional analysis developed to predict fiber distribution in ribbed sections. The model shows that parameters like mold closing speed and polymer viscosity can be optimized to decrease fiber matrix separation.
The influence of a stress concentrator on the mechanical properties of injected plastic parts was studied. Polystyrene plaques with different dimensions of a triangular concentrator were injected. Melt temperature, injection and holding/packing pressures and injection speed were modified in order to determine their influence on the stress concentrator factor (Kt). The experimental results were compared with the simulation ones. It was verified that Kt depends on geometrical parameters and process conditions of the injected plastic parts.
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Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
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