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

Analysis of Halo Effects on Injection Molded Parts

Amit Dharia, May 1999

The problem of a specific type of surface defect called tiger stripes" or "halos" on the injection molded parts of the thermoplastic olefin blend is investigated. First the method to reproduce such defects on the small parts is described and then the results of a rheological method to predict materials prone to producing tiger stripes are presented. Results indicate that both the molecular weight and relaxation behavior are critical determinants. Materials with large molecular weights as predicted by very high melt viscosity at zero shear rate and short relaxation time tend to form less tiger stripes."

Electrical Properties of Carbon Black(CB)-Filled Polypropylene/Ultra-High Molecular Weight Polyethylene Composites

Jiyun Feng, Chi-Ming Chan, May 1999

Carbon black(CB)-filled polypropylene(PP) /ultra-high molecular weight polyethylene (UHMWPE) composites were prepared by the conventional melt-mixing method. The electrical resistivity, positive temperature coefficient(PTC) effect, and morphology of the composites were elucidated in detail. CB particles were found to be selectively localized at the interface between PP matrix and UHMWPE particles or in the PP matrix due to the extremely high viscosity of UHMWPE. Double-PTC effects were also observed and discussed.

Solid State FTIR Analysis of Hydrogen-Bonded Domains in Synthetic Biopolymer Hybrid Silk-Like Materials

D.Y. Sogah, R.C. Claussen, M.J. Winningham, O. Rathore, May 1999

Novel silk-like hybrid-peptide polymers containing either parallel or anti-parallel ?-sheets templated by either phenoxathiin or xanthene derivatives have been prepared. Solid state FTIR spectroscopic studies confirm the presence of ?-sheets in the polymers. Building blocks that do not contain the rigid templates do not readily form the sheet structures.

LFT and GMT

J.C.M. de Bruijn, May 1999

Glass mat thermoplastics (GMT) are currently state-of-the-art materials for compression molding, with still hugh potentials. In Europe their unique position is attacked through the use of Long fibre thermoplastic (LFT) materials which are processed through the use of extrusion compression molding. Although raw and semi-finished product producers are fighting a media battle, it will be discussed how both materials can nicely exist alongside from the viewpoint of a finished product producer.

Time Dependent Crack Growth in Polyethylene with Emphasis on Environmental Attack

Paul B. Wells, Walter L. Bradley, Dave Register, Mark Lamborn, May 1999

This research seeks to determine the effect of chlorinated hot water on slow crack growth resistance in polyethylene using a test methodology that is quick and inexpensive. This will be done through the use of three point bend tests on specimens completely immersed in a bath of chlorinated hot water. The results will then be compared with results from the same test run without chlorinated hot water. Comparative data will be used to determine chlorine's effect.

Vibration Molding of Thermoplastic Composites

Robert P. Fried, May 1999

VIM (Vibrational Microlamination) is a new technology in the physical sciences. In VIM development, the physical, the chemical, and engineering technologies have been combined to contribute effective new knowledge.

Structure-Mechanical & Dynamic Mechanical Properties Relationship in Polyamide Based Thermoplastic Elastomeric Blends and Blocks

Anil K. Bhowmick, S. Ghosh, A. Jha, May 1999

Dynamic mechanical and mechanical properties of segmented polyamides composed of polyether and polyamide structural units of varying block lengths and thermoplastic elastomeric reactive blends of polyamide and acrylic rubber of varying interactions have been studied. The results are explained on the basis of the chemical structure and morphology of the systems.

Choosing a New Future - A Look at the Current Polystyrene Industry from Global and Market Perspectives and Opportunities for Stronger Growth

Kevin J. McQuade, May 1999

In a highly uncertain international business environment, the polystyrene industry still has attractive opportunities and needs to plan now to take advantage of the next turnaround when economic conditions improve. The industry has the power to choose its future by taking the right steps now to prepare for the opportunities that will emerge with the upturn.

Prediction of Complex Dynamic Behavior from Simple Deformations

Mohan Gounder, Alan Letton, May 1999

Many researchers have noted that characterizations based on sinusoidal tests alone provide misleading information regarding materials used in non-sinusoidal periodic applications. However, availability of commercial instruments that can evaluate materials in complex periodic deformations is rare. To address this problem, various nonsinusoidal periodic deformations are applied to a nitrile elastomer using a torsional rheometer and suitable modeling is employed to predict the behavior. Also it is shown that complex dynamic behavior can be predicted from simple deformations.

Capturing PVT Behavior of Injection-Molded Parts Using Hybrid Methods

Hubert Lobo, Twylene Bethard, May 1999

Polymer crystallization is the primary mechanism for shrinkage in semi-crystalline molded parts. Injection molding CAE utilizes PVT data to provide information about crystallization. Conventional PVT measurements do not reflect the true shrinkage behavior of the plastic because they do not subject the polymer to the same kind of thermal history as seen in the actual molding process. We introduce a novel hybrid technique to characterize the PVT relationship of molded parts, which accounts for cooling rate effects.

Structure Property Correlations in a New Rigid Rod Luminescent Conjugated Polymer, Polypyridine

A.P. Monkman, L.E. Horsburgh, M.E. Vaschetto, P.D. Hatton, H.D. Burrows, W. Brown, L. Pettersson, May 1999

Poly(2,5-pyridine diyl) is found to be a unique conjugated polymer in that it is a truly rigid rod polymer whilst being solution processible. It is a highly crystalline polymer with strong interchain interaction, yet is also highly luminescent. The structural properties of this most interesting material are presented together with the physical properties that ensue

The Effects of Slip and Antiblock Additives on the Oxygen Transmission Rate of Highly Permeable Polyolefin Plastomer Films

Jeffrey J. Wooster, May 1999

Slip and antiblock additives were determined to reduce significantly the oxygen, carbon dioxide, and water vapor transmission rates for highly permeable blown films made from polyolefin plastomers. At typical usage levels of 2500 ppm erucamide slip and 5000 ppm SiO2 antiblock, for example, oxygen transmission through a 0.8965 g/cm3 plastomer film is approximately 25% less than through a film containing no slip or antiblock additives.

Structure Versus Rheological Properties of Soft Plastics: The Case of Ep(D)M Polymers

Emmanuel G. Kontos, May 1999

In the world of polymers, EP(D)M's are considered as rubbers capable to become excellent elastomers upon vulcanization. This paper presents EP(D)M's as unique soft plastics and provides some basic relationships between molecular structure of EP(D)M and rheological properties as measured by dynamic mechanical spectrometers. The rheological properties discussed, primarily tan delta, affects greatly the processability of rubbers as well as of plastics which are not rubbers.

The Effects of Ultrahigh Shear Rates on Mechanical Properties

Derek Vargason, Daniel Fritts, May 1999

The industry has yet to determine the effects of ultrahigh shear rates during the injection molding process. During this research, an ultrahigh shear rate mold will be built and used to exceed a given materials shear rate limit. After regrinding the sheared and unsheared materials, a test specimen will be molded. Samples will be tested for mechanical properties. Comparisons will then be made and a shear rate limit for a given filled or unfilled material will be determined.

Effect of Blending of Styrenic Block Copolymer on Abrasive Wear of Thermoplastic Elastomers (TPEs)

Raquel Perez, May 1999

An experimental investigation has been conducted to assess the role of a styrenic block copolymer in modifying the wear properties of high performance thermoplastic elastomers. The TPEs which were evaluated are a polyurethane elastomer and a polyester elastomer. It was found that small amounts of the styrenic block copolymer increased the abrasive wear of these blend elastomers.

Modeling the Structural Evolution of Filled Polymers and Nanocomposites

Anna C. Balazs, May 1999

We simulate the motion of spherical particles in a phase separating binary mixture. We show that the addition of hard particles significantly changes both the speed and the morphology of the phase separation. The domain growth rate shows a nontrivial dependence on the particle density, in qualitative agreement with earlier experimental data. The results facilitate the development of filled polymers and nanocomposites for specific technological applications.

Nanoparticle Reinforcement of Nylon 6,6 Composites

Lloyd A. Goettler, Bruce A. Lysek, May 1999

Polymers have traditionally been reinforced with micron-sized fibers and fillers to improve their load-bearing capacity and/or thermal resistance. While generally cost-effective and structurally adequate for many applications, these materials usually lack good appearance and easy processing due to the relatively large size of the dispersed phase. Such disadvantages can be overcome by reducing particle size to nanoscale dimensions through several routes, including the delamination of certain mineral fillers.

Design of a Pressure Vessel of Oriented Polyolefins

Robert G. States III, May 1999

The scope of this project is to design and evaluate a plastic package for a product that generates internal pressure. The package will be made of a polyolefin that is capable of being oriented. The mechanical properties of the oriented polyolefin will be characterized. The data then will be used in a finite element package to optimize the package design and predict the final performance of the package.

Investigation of Methods Used to Determine Ejection Temperature for Injection Molding

Melissa Spring, Courtney Williams, May 1999

This paper presents a study on the different methods used to determine the ejection temperature applied to calculating the cooling times during processing of thermoplastic materials. These methods for determining ejection temperature are contrasted with each other and then compared to PVT data. This was done to determine whether or not PVT graphs could provide a reasonable estimate, or alternative, of determining ejection temperature.

Comparison of Extrusion and Injection Blow Molded Bottles

Matthew R. Cribbs, May 1999

Processing decisions are often made between blowing bottles by the extrusion or injection blow molding technique in companies having both capabilities. Where parison melt strength is not a problem, one of the major considerations is the strength of the resulting bottle. Using the same bottle geometry and same plastic material under optimum processing condition for each method tensile testing will be performed. The tensile specimens will be die cut from side wall panels and compared. Results will shoe the mechanical differences generated by the two approaches.