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

The Effects of Shear Imbalances on Intra-Cavity Melt Flow Using Varying Melt Flow Rates in Thermoplastic Elastomers and Vulcanizates

Eric D. Baluh, Mikael S. Wagner, May 2007

The high shear developed in a runner creates significant melt variations and is the source of shear induced mold filling imbalances in geometrically balanced runner runners. These same shear induced melt variations can also create unexpected filling patterns in a single cavity mold. If this uneven filling pattern could be manipulated then shear induced melt variations can be used as a tool in industry. The focus of this paper is to find if the filling pattern with thermoplastic elastomers (TPE) and thermoplastic vulcanizates (TPV) can be manipulated by varying injection flow rate.

Analysis of the Relative Effects of Loading Agents and Their Interactions as a Function of Core Resistivity in Thermoset Polyurethane Foam Parts

Daniel Brittingham, May 2007

While there has been an increase in the use of certain polymers for electrically conductive applications [5], thermoset polyurethane foams have been primarily used in applications that do not require any electrical conductivity. The electrically insulative properties of these materials can be accentuated by the presence of air pockets inside of the foam parts [4]. This investigation analyzes the effect loading agents have on electrical conductivity on thermoset polyurethane foam containing a conductive core. This paper discusses the relative effects of two loading agents – carbon black and graphite – on resistivity of a thermoset urethane part containing a conductive core as determined by statistical analysis through designed experiments.

Penetration Length, Thickness and Crystallization Behavior of Water-Assisted Injection Molded Part

Han-Xiong Huang, Zhi-Wu Deng, Xu-Hui Liu, May 2007

Water-assisted injection molding experiments were carried out on newly developed equipment in our lab. The effects of four processing parameters, short-shot size, melt temperature, water injection delay time, and water pressure, on the water penetration length and residual wall thickness of water-assisted injection molded polypropylene curved pipe were investigated. The crystallization behavior difference between the beginning and the end of the water channel of the curved pipe was analyzed using differential scanning calorimetry.

Predicting Processing Parameters for Water-Assisted Injection Molding Based on Inverse GA-LMBP Neural Network

Jian-Min He, Han-Xiong Huang, May 2007

The water-assisted injection molding (WAIM) is a new injection molding technique. It is difficult to describe the WAIM process using mathematical method due to its complexity. In this work, a predicting model for the WAIM process was developed via an inverse hybrid algorithm combining genetic algorithm (GA) with Levenberg-Marquardt back propagation (LMBP) neural network. By adopting the model, processing parameters, such as melt temperature, water pressure, water injection delay time, and short-shot size, can be predicted quickly and accurately for desired residual wall thickness of molded parts.

Selection of Colorants and Other Additives for Durable Products

James J. Bal, May 2007

Polyolefins are utilized frequently in durable products that call for extended life in a variety of environmental conditions. Many of these products require color and almost all require and enhanced degree of resistance to the stresses of an exterior environment. The selection of plastic colorants that can withstand harsh environmental conditions is critical to ensuring the long term appearance of a polyolefin based durable product. Likewise, the correct choice of plastic additives for exterior applications must be made in order to ensure acceptable product appearance and performance over time.This paper examines key design considerations for durable polyolefin products in terms of additive selection. Special consideration is made in terms of selecting colorants that are considered non-toxic. A practical example is presented.

Appraisement of the Engineering Properties of the Chemical Resistant Laminate in Products

Rakhil M. Sinelnikova, Valery G. Makarov, May 2007

Polymer composites on epoxy vinyl ester resins serve the needs of wide range of industrial chemical processes with the final products, such as coverings, coverings of floors, etc.To provide a good corrosion barrier over concrete, metal etc, it is necessary to use a chemical resistant laminate (CRL). The practice of FRP application shows the existence of an optimum ratio between numbers of powder bonded chopped strand mat layers and engineering properties of CRL.Analyses of scale (size) effect of strength and permeability are carried out.The analytical dependence of tensile strength and permeability from a thickness is used for appraisement of the engineering properties of CRL in products.

New Transparent Copolycarbonate Compositions with Low OSU Heat Release Values

Jianbo Di, Gary Davis, Katherine Jackson, Ahmed El Kassmi, Brian Mullen, Laura Schultz, Moitreyee Sinha, Paul D. Sybert, Jenny Zhang, May 2007

New polyester carbonate copolymers afford the first resins with low color, high transmission and low haze combined with low OSU Heat Release values. In addition, the fabricated articles can be hard coated to provide improved levels of scratch resistance. These compositions can be varied to maximize the various mechanical properties depending on the needs of the application. The excellent clarity combined with OSU 65/65 compliance allow for applications such as interior transportation windows/dust covers, partitions, mirrors and lighting lenses. The excellent colorability also allows for the fabrication of interior opaque components for the transportation industry.

In-Situ Formation of Microfibrillar Morphology in Polymer Blends

Roman Cermák, Martina Polášková, Jakub Kalus, Jana Výchop?ová, Martin Obadal, May 2007

The work focuses on microfibrillar-phase formation in polymer blends during extrusion through a die with semihyperbolic-converging channel. For these purposes, three polyethylene/polypropylene blends with the mixing ratios (wt./wt.) 80/20, 70/30 and 60/40 were prepared. Final structure and properties of extruded blends were examined using electron microscopy, wide-angle X-ray scattering, differential scanning calorimetry and tensile testing. It is demonstrated that the formation of microfibrillar-phase morphology is achieved in all blends, independent of their mixing ratios. However, the structure and properties of these microfibrillar-phase composites are strongly influenced by mixing parameters.

SMC Consistency Test Methods – Viscosity Methods

Jim Bono, September 2006

This presentationwill look at the study of available viscosity test methods to minimize variation associated with testing equipment. The test methods include the current industry standard HBT viscometers and Brookfield’s new Soft Solids Tester SST2000 which are compared for performance in SMC matrix samples.