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.
|= Members Only|
Polypropylene Morphology in Micro-Injection Molding of Rectangular Groove
In micro-injection molding process, the dimension of the characteristic geometry can be similar to morphological feature size inside the polymer. This work investigates the crystalline morphology in the injection-molded polypropylene parts. It has been found that development of crystalline structure affects the filling flow. The molded micro-structure shows the crystalline growth on the surface. The crystalline structure inside micro-groove can be stretched crystal or spherulite.
Shrinkage, Warpage and Residual Stresses of Injection Molded Parts
The shrinkage and warpage behavior of injection molded parts is very complex. By using a new measuring method it was shown for the first time that the warpage can be classified as warping and distortion. In general, warpage can only be reduced substantially by a sufficiently high volumetric compensation in the holding pressure phase. Residual stress measurements show, deviating from the literature, that flow induced residual stresses can also induce compressive stresses in the part core due to pressure holding effects.
Characterization of Scratch Properties of Talc-Filled Polypropylene with Various Melt Indices
Scratch properties of talc-filled polypropylene was quantitatively evaluated by critical loads. Scratch test was conducted following ASTM D7027 standard. Melt index (MI) and talc content were varied to investigate wide range of composition. Tensile test was conducted according to ISO 527 and scratch properties are analyzed in terms of tensile properties.
Investigating Filler Orientation of Functionalized Thermoset Molding Compounds during Injection Molding
Thermoset molding compounds are showing great potentials in applications that demands high temperatures, high media resistance and good mechanical properties. Customized properties such as enhanced heat conductivity or magnetic properties that can be achieved through functionalization are often sought after in the thermoset as well as in the thermoplastic industry. This paper deals with the orientation of magnetic and heat conductive fillers in epoxy molding compounds, which are essential for part design and process control.
Development of an Approach to Determine Minimum Amplitude Required for Ultrasonic Welding
One of the most important variables for ultrasonic welding is amplitude. While recommended amplitude guidelines are available for many generic materials based on accumulated industry experience, use of specialized and newly developed materials is rapidly increasing. To that end, it is desired to have a method for experimentally determining the minimum amplitude required for a material. This work investigates one possible method to determine minimum required amplitude.
Using Coextrusion Layer Splitting to Improve Film Tear Strength
This paper shows how to employ layer splitting in coextrusion to improve tear strength of elastic films. The improvement is done without changing the chemical composition or adding a strength-enhancing polymer. The present work is focused on multilayer elastomeric films made from polymers in one layer that are immiscible in the polymers in the adjacent layer.
Permeability of Nanoporous PEI
Novel open-cell foams were created using the solid-state foaming process in polyetherimide (PEI). The cell size is in the 50 – 150 nm range. The structures’ fluid permeability, gas diffusivity, and tortuosity were determined by applying classical models to experimental data. This new class of materials is expected to have a variety of applications such as nanofilters for dialysis/aerosols, slow release of volatile substances in medical or agricultural fields, and others.
A New Approach to Mold Venting: Alternative Venting Valves
The article discusses commonly used systems for mold venting and their limitations, introducing therefore alternative dynamic venting valves that can help overcome such limitations and improve mold performance.
A New Strength Tensor Based Failure Criterion for Anisotropic Materials
A recently published 3D failure criterion  for anisotropic materials that incorporates stress interactions is presented. The strength tensor model includes fourth order strength tensor stress interaction components that can be computed based on the slope of the failure surface at distinct stress axes intersections, making the model apt to fit failure surfaces for a variety of anisotropic materials. Experimental data from the literature for unidirectional FRP’s, an anisotropic paperboard material and textile reinforced composites are used to validate the model.
Failure Criterion for SLS Additive Manufactured Parts
A 3D failure criterion for anisotropic materials that incorporates stress interactions is implemented to predict failure of selective laser sintered parts. Special test specimens were designed, manufactured and tested. Results show that the failure of additive manufactured parts is strongly influenced by the interaction between stresses. The test data shows an excellent fit with a tensor based failure criterion that includes interaction strength tensor components .
Time-Dependent Delamination of Plastic Film: Observation and Modeling
The paper is aimed at the observation and modeling of thin plastic film delamination from a substrate and its progression. The authors are addressing the following issues: 1) what physical and geometrical parameters of the film-adhesive-substrate system play the major role in initiation and progression of delamination; 2) what is the root cause of slow delamination growth in time; and 3) formulation of a quantitative model of the process. A brief review of existing approaches, simple experimental setup, observations and the modeling results are reported.
New Developments in High Energy Electron Beam Induced Long Chain Branched Polyolefins for Low Density, Non-Crosslinked Foams
The purpose of this paper is to provide an update in the development and commercialization of radiation modified, linear polyolefins including linear low density polyethylene (LLDPE), high density polyethylene (HDPE), polypropylene (PP) and ethylene vinyl acetate (EVA) that have been used to produce non-crosslinked, low density foams. This is an important commercial development in that now it is possible to access a broader range of foam properties through material selection to meet challenging performance requirements.
Innovation in Emerging Areas in Packaging
Markets trends of cost reduction, consumer convenience, sustainability & down-gauging drive the need for new and improved packaging solutions. Development of such solutions requires a look across the entire value chain – an Asset to Market look. This talk will focus on what is required for a successful packaging solutions to be launched in a competitive space. Key examples will be presented and will cover the trends related to recyclability and downgaging.
Effect of Polymer Design and Formulation on the Performance of Water-Based Acrylic Dispersions for Heat Seal Lacquers
Heat seal lacquer materials are tailored for the types of substrate being sealed together and contents of the package. Both polymer properties and formulation variables can be chosen to target bond strength, activation temperature, and bond failure mode, all being optimized for a given end use. This paper will discuss examples of different polymer properties and formulation variables on the end-use performance in a heat seal lacquer.
Demonstration of an Effective Design Validation Tool for 3D Printed Injection Molds (3DPIM)
Injection molding, the process of injecting plastic material into a mold cavity where it cools and hardens to the configuration of the cavity, is one of the world's most popular manufacturing processes. It is best used to mass produce highly accurate, and often complex, end-user parts.
Business Platform in the Modern Textil
Be Functional, smart and interactive are the most valuable asset to become a reference in our markets. The global S-textile market is already an 3 billion dollars business that is expect to exhibit double-digit growth, which are very interesting to go ahead with the implementation of projects of Biopolymer, Bio composites and nanotechnology and microelectronic in this issue. Please note the market by moving beyond traditional path of what means value and fulfilling business future.
Viscosity and Screw Assembly Effects on Mechanical Properties of Glass Fiber Reinforced Nylon Compounds
Short glass fibers are widely employed in reinforcement of nylon compounds to significantly improve mechanical properties. These properties are dictated by fiber length and orientation distributions in the compounds. Fiber breakage takes place during the compounding process. When the fibers break into sub-critical length, the reinforcement of the compound is limited. This paper used a full factorial design investigating the effects of nylon’s viscosity and twin screw extruder’s screw configuration on glass fiber length retention and mechanical properties of the final compounds.
Effect Nanoclay Addition on the Compatibility and Diffusion Properties of Commercial Gasoline through Polymer Membranes
In this work, we consider the effect of the addition of functionalized clay particles to a poly (tetramethylene oxide) (PTMO) based polyurethane that is a candidate to be used as for flexible storage containment for a variety military fuels. We have synthesized urethanes with layered silicate inorganic nanoclay concentrations varying from 0% to 10% by weight and evaluated the diffusion of commercial gasoline.
Design Optimization of Maddock Mixers for Single-Screw Extrusion Using Numerical Simulation
Maddock-style mixers are used extensively on single-screw extruder screws to disperse materials into the molten resin matrix. Since the time LeRoy invented the device and Maddock perfected and commercialized it, the device has undergone several innovations. The goal of this paper is to describe the optimal flute geometry and mixing undercut dimension for a Maddock mixer with the goal of mitigating degradation gels and maximizing dispersive mixing efficiency.
An Improved Algorithm for Determining Energy Interchange between Heaters and Sheet in Thermoforming
The general Stokesian-generated exact equation for radiant interchange between heaters and sheet produces results similar to the differential method but is more versatile. Often, when a sheet of plastic is heated prior to forming it into a part, there are planes of heaters above and below the sheet. The heaters often have many segments, with each segment temperature controllable. As a result, the energy input to the sheet can be "shaped" to provide uniform heating of the sheet.
We're sorry, but your current web site security status does not grant you access to the resource you are attempting to view.