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

Predicting the Heat Seal Performance of Ionomer Films

Barry A. Morris, May 2002

The heat seal strength of a flexible plastic package depends on the extent of molecular penetration at the seal interface, which in turn is a function of sealing jaw temperature, line speed and film thickness. Thinner films reach the maximum seal strength at lower jaw temperature or faster line speed than thicker films. A model is developed that combines heat transfer with molecular diffusion at the interface. The model points to how laboratory data may be used to predict the sealing performance of ionomers in high-speed packaging lines.

Prediction of Failure and Fracture Mechanisms of Fiber Reinforced Composites Using Finite Element Analysis

E. Ghassemieh, May 2002

A finite element (FE) model is developed to study the stress transfer from matrix to fiber in a short fiber reinforced composite. The critical length of fibers to insure the ultimate stress transfer, is predicted by the model. The interfacial stresses evaluated by FE model are compared with the well known shear lag (SL) and modified shear lag (MSL) models. The competing failure mechanism in short fiber reinforced composites and the triggering stresses for that are recognized.

Prediction of Parison Swell in Extrusion Blow Molding Using Neural Network Method

Han-Xiong Huang, Chang-Ming Liao, May 2002

A neural-network-based model approach is present where the effect of the die temperature and flow rate on the diameter and thickness swells of parison in the continuous extrusion blow molding of HDPE was incorporated. Comparison of the neural network model predictions with experimental data yields very agreement and demonstrates that the network model can predict the parison swells at different processing parameters at a high degree of precision (within 0.001).

Pressure Distribution in Screw Extruders

C. Rauwendaal, May 2002

Pressure in extruders is usually measured only at the end of the extruder barrel (P-barrel) and at the die inlet (P-die). In some extruders multiple pressure transducers are placed along the length of the extruder barrel so that the axial pressure profile can be measured. Such information provides invaluable information about the behavior of the extruder and is extremely useful in troubleshooting extrusion problems. This paper discusses various pressure profiles and explains what they tell us about the processes occurring within the extruder.

Product Designer Wish List Can Be Done Now!

Paul E. Allen, May 2002

This paper will cover the use of Patent Number: 5,932,164 and its effect in product design. It will briefly review the economic and physical barriers put on the product designer by the injection molding process. These include, draft angle, surface finish, and physical ejector placement. It will show how a designer can design a product with minimal draft angle, and/or no mechanical ejector system, and/or less expensive mold, and/or less cost to produce.The above will include very deep texture with little or no draft angle, and no stripper ring (to flash) on round parts.

Properties of High Density Polyethylene and Poly(Ethylene-CO-octene) Blends

Marisa C.G. Rocha, Maria José O.C. Guimarães, Fernanda B.M. Coutinho, May 2002

In this work the mechanical properties of high density polyethylene toughened with two grades of metallocene elastomers based on ethylene/1-octene (EOC) were studied . It was observed a synergistic effect on the tensile properties and a supertough behavior for blends with elastomer concentrations higher than 5 wt%. Cavitation, plastic deformation and fibrillized cavitation were the operating mechanisms in the deformation processes.

PVC/Wood Flour Composites Compatibilized with Chlorinated Polyethylene

Virginia O. Guffey, Amiel B. Sabbagh, May 2002

Chlorinated polyethylene (CPE) has been demonstrated to be an effective compatibilizer for dissimilar materials in various mixed-polymer or recycled-polymer systems. In this paper the use of chlorinated polyethylene to compatibilize polymer/natural fiber composites is discussed. Examples of applications in PVC/wood flour composites are given.

Raman Spectroscopy: A Useful Tool for Characterizing the Polymerization Kinetics of Polyurethanes

Shane Parnell, K. Min, M. Cakmak, May 2002

In this study, the polymerization kinetics of an uncatalyzed polyester based thermoplastic polyurethane formulation was investigated with Raman spectroscopy. The normalized scattering intensity of the 1530 cm-1 diisocyanate band was used to calculate conversion as a function of time. Kinetic parameters obtained from these experiments correlated well with those obtained from analogous calorimetric experiments.

Real-Time Monitoring of Fluorescence Anisotropy and Temperature during Processing of Biaxially Stretched Polypropylene Film

Anthony J. Bur, Steven C. Roth, May 2002

Using an optical sensor, fluorescence anisotropy and fluorescence temperature measurements were carried out during the processing of biaxially stretched polypropylene films in a tenter. The fluorescence derived from a dye that was doped into the resin. Anisotropy measurements were made as a function of machine stretching ratios.

Residual Strength-Based Lifetime Prediction of Polymeric Composite Materials

Scott Case, John Bausano, Jack Lesko, May 2002

In this work, we present the philosophy of a lifetime prediction scheme for polymeric composite materials based upon damage accumulation concepts that allow the calculation of the residual strength. Key features of the method are that it readily admits the effects of multiple damage mechanisms and can be used to develop design guidelines based upon reliability concepts.

Reverse Engineering of Polymeric Materials

J.C.J. Bart, May 2002

Introduction The real value of polymer/additive analysis becomes apparent when it is put to solve relevant industrial problems, to study important materials or to control vital processes. At a par with Manufacturing or Operational Excellence programs industry also strives for Analytical Excellence. In this paper we present best industrial practices related to the analysis of additives in polymers.

A Review of Recent U.S. Utility Patents on Tamper-Evident Resealable Push-Pull Bottle Closures

Amad Tayebi, May 2002

A review of design options, disclosed in recent U.S. utility patents, for tamper evidence in resealable push-pull bottle closures is presented. Each of the selected patents is analyzed with regard to choice of location and nature of tamper evidence means.

Rheological and Tensile Strength Characteristics of Polymer Melts

M. Zatloukal, P. Štach, P. Liu, J. Vl?ek, P. Sáha, May 2002

Cogswell [1] and Wagner [2] methodology was employed to determine the rheological and tensile strength properties of two LDPEs and two metallocene LLDPEs resins through capillary and Haul-off (Rheotens-like) measurements. It has been shown that the tensile strength properties obtained by both methods yield almost the same values. Moreover, these values can be correlated to the drawability in tubular film blowing for corresponding materials.

Rheological and Thermoanalytical Investigations of a Class A" LP-SMC Paste"

Marco Wacker, Gottfried W. Ehrenstein, May 2002

Because of the good light-weight potential, the good resistance against corrosion and a good permeability for electro-magnetic waves more often SMC parts will be used in european automotive applications. As a result of varying qualities of the SMC prepreg or paste there exist still problems during the compression molding process.The paper discusses the used measuring methods for quality control and the influence of aging effect, which occurs during the storage of Sheet Molding Compound (SMC), on the viscosity and the curing behavior of a LP-SMC paste.

Root Cause Analysis; Fundamentals and Applications

Rabeh H. Elleithy, May 2002

This paper discusses the fundamentals of root cause analysis in identifying a failure, investigating its causes, and suggesting the corrective actions. Examples of hinge failure analysis are discussed. A descriptive statement of each failure is formulated followed by the suggestion of its probable causes and their investigation. Finally, the most probable causes are identified and recommendations are made. The cases at hand discuss the importance of material choice and part design to hinges failure.

Sailing Unknown Waters

Jiri George Drobny, May 2002

Doing business in a different culture represents a formidable challenge. This paper is a case study covering marketing chemical products from post-Communist region of the former Czechoslovakia in the USA and Western Europe. Both positive and negative factors as well as lessons learned will be discussed.

Scratch Behavior of Polypropylene-Based Blends

M. Kotaki, M. Wong, C. Xiang, H.-J. Sue, May 2002

Scratch behaviors of model polypropylene (PP) based blends are investigated. The model PP blends are PP, PP/ethylene-propylene rubber/talc, and PP/styrene-butadiene-styrene/clay. The effects of filler and rubber additions on the scratch behavior are correlated with material property and morphology of the PP blends. The PP/SBS/clay system, which contains sub-micrometer size clay inside the rubber particles, exhibits the best scratch resistance. Material parameters and surface characteristics that contribute to improvements in scratch resistance in PP blends are discussed.

Screws for Plastics Processing

James D. Frankland, May 2002

Maintenance of a single screws dimensions during its service life is discussed due to the magnitude of the dimensional deterioration on overall process performance. Proper choice of materials of construction for screws can greatly increase service life. A simplified analysis for determining when to replace a screw is presented to assist in proper maintenance.

Self-Optimizing MPC of Injection Velocity during Mold Fill

Rodney Lakhram, Rickey Dubay, May 2002

The dynamics involved during mold fill is complex and temperature dependent. Presently, the controllers for achieving a desired injection velocity setpoint profile are independent of processing conditions in plastic injection molding. A generic, online control procedure to re-define the controller parameters was developed from dynamic models to achieve good tracking of injection velocity setpoint profiles during simulations of mold filling. This generic control procedure provided an effective and systematic approach for any plastic material and different processing conditions.

Shear Effects on Extruded Foam Products

S.T. Lee, May 2002

Shear has been found an important nucleation parameter in the foam extrusion process. In this paper, further shear effects on foam properties are presented. At increased shear, foam expansion decreases, which suggests die swell promote competing mechanisms. Extension rate was found to correlate with expansion and compression strength. Also investigated was residence time at low shear to restore the shear thinning in the counter-rotating twin screw extruder. Shear and extension rate effects are addressed for foaming and foamed products.