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.
An optical technique for monitoring the solidification of thermoplastics was implemented and studied. A He-Ne laser illuminated the mold cavity through an optical window and a photomultiplier measured the intensity of reflected light during the molding cycle. The light measured is a complex composite of reflection and refraction from crystallites, the mold wall and as many as six interfaces. Polystyrene, polypropylene and high-density polyethylene were used. Further work is required to use this technique for process control purposes.
Phase inversion during compounding of low-viscosity ratio polystyrene/polyethylene blends was studied in two different batch mixers. Using a constant maximum-shear-rate as the scale-up criterion, longer mixing times were required in the large mixer due to its lower specific area. A new triangular element blade design was used to obtain different batch sizes in the same mixer. On scale-up with these blades, a constant specific area was maintained and equal mixing times to phase inversion were observed.
A numerical algorithm to automatically design polymer extrusion dies is developed. The method uses an adaptive finite element model and shape optimization methodology to define the transition section and the land lengths of a profile die. The ultimate goal of this work is to develop a simulation tool that could be used by extrusion die designers which functions like the CAD-integrated simulation tools available for injection mold designers today.
A Designed Experiment was conducted to determine the effects of injection molding processing parameters on hinge life of a styrene-butadiene copolymer. Resin melt temperature, mold temperature, 1st stage velocity, and 2nd stage pressure were varied and mathematically related to the number of flexes required to cause hinge failure. Best hinge life was observed using high melt temperature, high mold temperature, high 1st stage velocity, and low 2nd stage pressure. Some variation in this trend was observed at low melt and mold temperatures.
Birefringence distribution of an injection-molded lens is numerically calculated. A simplified numerical approach is proposed that can be used for studying the effect of key molding parameters and evaluating optical property of the lens. Numerical results showed that the melt temperature and holding pressure have significant effects on the optical property of the lens. It also suggested that the holding pressure should be determined with special care to obtain lenses with satisfactory optical characteristics.
Short-term stress relaxation of polycarbonate parts, with non-uniform tensile stress, is compared to that under uniform tensile stress. The non-uniformity in stress distribution is induced by drilling small holes in the test specimens. The data obtained provide helpful design considerations in pin-type fastening assemblies.
Injection molded polycarbonate parts, with and without small drilled holes, were subjected to a three-point flexural deformation. A special bending test set-up was designed to maximize the exterior fiber tensile strain in the drilled hole zone. The data show a significant change in behavior of polycarbonate under flexural deformation and brittle-like fracture in the drilled hole zone.
In this article we give a brief introduction to lattice Boltzmann methods, show why they are a particularly useful tool for the examination of complex multiphase systems and point out their advantages over traditional CFD methods. We present an overview of the method that allows simulation of viscoelastic two component systems, as well as some application of the method to simple model systems.
While polyvinyl chloride (PVC) has been employed in the calendering industry for many years, other polymers have not been as widely used. Ethylene styrene interpolymers (ESI) demonstrate the requisite rheological properties and thermal stability to be successfully used in the calendering process. Commercial scale validations were performed on ESI based formulations. Examples of the applicability of ESI to calendering are discussed.
The processability of polyethylene for rotational molding applications is dependent on both viscosity and elasticity. Two samples were compared with equivalent viscosities but differing degrees of elasticity. The resin with decreased elasticity had a shorter cook time and rotomolded parts exhibited better physical properties and fewer air bubbles. Further testing is proposed to quantify more clearly the differences in elasticity.
Prior to processing, composite materials must be consolidated to allow the formation of a continuous polymer matrix phase and the removal of voids. The composite material studied in this research consists of continuous commingled glass and polypropylene rovings. The consolidation of this material as well as mats composed of unidirectional and woven glass rovings were studied using a specially designed tool mounted on a compression machine. Fiber volume fractions with and without polymer were measured as a function of compressive stress.
Glass fibers used in this study are silane-treated woven glass mats and anhydride-treated polypropylene woven glass mats. The influence of these treatments on the epoxy resin curing kinetics is studied. Isothermal and dynamic kinetic parameters from Differential Scanning Calorimetry (DSC) are determined and compared. Based on enthalpies as a function of time results, the autocatalytic model is chosen for the analysis.
The morphology of a compatibilized polyethylene terephthlate and thermotropic liquid crystalline copolyester blend is investigated via in-line optical microscopy and light scattering. It was found that the droplet-fiber transition in the liquid crystalline polymer is dependent upon the reactivity, the viscosity ratio and the shear field. The fibers are strongly oriented along the flow direction. The formation, deformation and stability of fiber microstructure under different flow conditions are discussed.
The self-nucleation behavior of the polyethylene (PE) block within polystyrene-block-poly(ethylene-co-butylene)-block-polycaprolactone triblock copolymers was investigated. The extent of self-nucleation was found to be highly dependent on the PE content of the copolymers. The self-nucleation was almost completely suppressed when the PE content was 15% by weight.
Thermogravimetry (TG) is an important tool for materials characterization. Hyphenated and multihyphenated methods greatly enlarge the scope of TG. Some thirty different experimental approaches were identified, many with a proven record, but some new and promising but in need of confirmation, such as video-imaging-TG, flash-TG- MS and quench-TG. A review of the state of modern thermogravimetry is given.
Strengths and weaknesses of thermogravimetry - mass spectrometry (TG-MS) in qualitative and quantitative industrial problem solving are outlined. The main features of the TG-MS hardware components are reported. Emphasis is laid on the great variety in design options, both for the TG, MS and interface components. The user's requirements for ideal TG-MS instrumentation are described and hyphenated TG-MS options are evaluated. HRTG-EI/SI QMS extended with a chemometrics software package is currently the most advanced option.
A series of alkyltin 2-ethylhexyl mercaptopropionates was synthesized and their structure and equilibria with alkyltin 2-ethylhexyl thioglycolates and alkyltin chlorides studied by IR and 119Sn NMR. Compatibility with PVC was determined using DMA analysis of glass transition temperatures. The implications of these results on PVC stabilization are discussed.
The objective of this presentation is to discuss the implementation of a non-contact scanning inspection method that can reduce product development lead times by greatly reducing the time to qualify and/or quantify a product for production. The equipment, requirements, and methodology of this CAD based inspection method will be discussed. Additionally, case studies supporting this advanced inspection process will be presented.
This work characterizes the deformation and breakup of a single drop subjected to a sudden onset shear flow. The drop is immersed in a second fluid with which it is immiscible. A cylindrical couette device is used to create simple shear flow on a time scale which is extremely short compared to the time scale of the deformation of the drop. Two breakup mechanisms were observed:elongative end pinching and capillary wave breakup.
Weatherable polycarbonate sheet can be produced by coextruding a cap layer containing a UV absorber over a minimally-stabilized bulk layer. A new UV absorber based on hydroxyphenyltriazine chemistry has been developed that is especially suited to this application. The product provides superior long term weatherability due to its strong UV absorbance and its excellent photostability. It is also relatively nonvolatile, and has only a minimal effect on melt viscosity.
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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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