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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Extruded Open-Cell Foams Using Two Semi-Crystalline Polymers with Different Crystallization Temperatures
This paper presents an extrusion-based open-cell foaming process with polypropylene (PP)/metallocene polyethylene (mPE) and PP/low-density polyethylene (LDPE) blends. The basic strategy for achieving a high open-cell content is to induce a hard/soft melt structure using two semi-crystalline polymers with distinctively different crystallization temperatures (Tc), and to foam this non-homogeneous melt structure with supercritical CO2. The effects of polymer blending, die geometry, and temperature on cell opening were investigated in this study.
New Non-Hygroscopic Thermoplastic Vulcanizates with Improved Colorability and Weatherability
A new line of non-hygroscopic thermoplastic vulcanizates (TPVs) has been developed for applications requiring both color and photo-oxidative stability. These products span the hardness range from 20A to 50D and offer superior oil resistance and compression set. In this paper, we will discuss the properties of the new TPVs, including non-hygroscopicity, oil resistance, compression set, color consistency, colorability and weatherability.
Development of Damping Machine Augmented Composite Materials
This work investigates energy dissipation in machine augmented composite (MAC) materials consisting of small machines in a matrix. The machines are fluid-filled tubes, and the tube cross-sectional geometry causes fluid flow when deformed. Dimensional analysis identifies the ratio of solid moduli to the product of driving frequency and fluid viscosity as an important parameter. Finite element models predict the performance of the MAC lamina. The highest energy dissipation predicted is 0.8 out of 1.0.
Processing and Properties Optimization of Dynamic Injection-Molded PP
With the Taguchi method, the process parameters of dynamic injection molding are optimized and the relationship between processing conditions and the physical properties of isotactic polypropylene is explored. The results show that vibration frequency and vibration amplitude have greater influences on mechanical properties of isotactic polypropylene than injection velocity and packing pressure in most of our experiments. The samples’ impact strength could be improved by about 40% with optimum parameters. The morphology and crystallinity are also explored with DSC and WAXD.
Active Polymer Composite for MEMS Applications
Finite element analysis (FEA) simulated the performance of an active polymer-matrix-composite material. Microscale muscle elements actuate the material. The muscle element contracts longitudinally, expands transversely, and twists when pressurized. A coupled elastic/piezoelectric element provided the response of the muscles to actuation and 3D elastic coupling of the lamina. The contractions of isolated elements and of a lamina were approximately the same; elastic coupling of elements within the lamina produced novel out of plane deformation.
Increasing the End-Use Temperature of TPU Products
TPU products are well known for their mechanical properties and wear resistance. However, in comparison to vulcanized rubber TPU materials have a lower softening point (limited end use temperature) and a limited elasticity (elongation set) preventing the use of TPU in some interesting applications. Here we introduce a family of new cross-linking agents and how they can improve these properties. Application examples are shown to demonstrate how these improvements can be utilized.
Tailoring of Multi-Component Crystalline Systems in Isotactic Polypropylene
A novel method for the preparation of unique 3-phase crystalline systems in isotactic polypropylene (iPP) has been proved. It is based on a synergy application of a specific ?-nucleating agent and high pressure during crystallization. The ? phase formation is supported by elevated pressure and high temperature during iPP crystallization; in this case, the growth of both ? and ? phase was significantly suppressed. Nevertheless, in the course of crystallization at lower pressure and/or lower temperatures, strong ?-nucleation efficiency of NU100 favored the formation of ? phase.
Mechanical Properties Enhancement via Non-Conventional Injection Molding
This work explores the possibility to expand the limited mechanical properties enhancement margins, typical for conventional injection molding, through the application of non-conventional techniques. The processing-structure-properties relationships encountered in two microstructure control methods (Scorim and Push- Pull) and three two-component techniques (Sandwich molding, Monosandwich molding and Overmolding) are evaluated and discussed.
Terahertz Imaging as a New Tool to Study Dispersion in Polymeric Compounds
We use terahertz (THz) imaging to study polymeric compounds of polypropylene and the flame retardant agent Mg(OH)2 obtained for different compounding conditions. Our data demonstrate that THz imaging is a powerful tool to evaluate the degree of dispersion in polymeric compounds.
Modeling for Counter-Rotating Twin Screw Extrusion
Based on our previous experimental studies for polymer behavior in a closely intermeshing counterrotating twin-screw extruder of a modular Leistritz design a composite model for the process is discussed. The model includes solids conveying, melting and melt conveying. Melting model involves both mechanical working of pellets in the inter-screw region and heat transfer from the barrel to the pellets.
Effect of Screw Design on Polyethylene Blown Film Processing
The influence of extruder screw design on the extrusion blown film processing characteristics of four polyethylene melts was studied. A barrier and standard compression screw were evaluated and process measurements including; process energy, melt pressure and melt temperature determined. Screw design had significant influence on melt throughput and specific energy.
Effect of Vibration Shear on Polystyrene Cell Morphology
A novel microcellular processing experimental setup is developed. With this setup, an oscillatory shear flow is superimposed perpendicular to a steady shear flow during microcellualr processing. The effects of processing condition such as processing pressure, shear rate and vibration frequency on polystyrene cell morphology are investigated. The results show that the cell density increase and cell size decreases with the increase of processing pressure, shear rate and vibration frequency.
In-Situ Observation of Orientation during Injection Molding with a Delayed Packing Stage
In-situ, real time monitoring of melt birefringence during injection molding of SAN provides insight into the development of molecular orientation when the packing/holding phase is delayed relative to the fill phase. Observation of melt birefringence is accomplished through the use of a custom-built mold and video imaging. The effects on orientation are similar to those observed using Vibration Assisted Injection Molding (VAIM) and provide a similar increase in the tensile strength of molded ASTM specimens.
Growth through Innovation
Today’s business environment is more challenging than ever. Globalization, outsourcing, consolidation and increasing raw material prices impact our business daily.Innovation takes many paths. In today’s environment, innovation must provide value, which translates into growth. The simplest and in many cases, the most rewarding innovation is achieved by recognizing the synergy between ideas that are not obviously connected.
Mechanical Design of Short-Fiber Reinforced Injection Molded Parts in 3D
By means of integrative simulation the anisotropy of short-fiber reinforced thermoplastics can be selectively exploited for the development of highly-stressed injection molded parts. The results of a complete 3D-calculation of the injection molding process using 3D-SIGMA software provide the basis for that. An interface and special user subroutines for the FEA program ABAQUS/Standard then permit the accomplishment of anisotropic structural analyses. Thus a precise mechanical design of short-fiber reinforced injection molded parts is possible almost without additional work.
Describing the Non-Linear Viscoelastic Material Behavior of Thermoplastics
The significance of structural analyses (FEA) for the dimensioning of plastic parts is heavily dependent on the material model used to describe the mechanical behavior. At the Institute of Plastics Processing (IKV) a new nonlinear viscoelastic material description was developed and implemented as a subroutine in the ABAQUS/Standard FEA program. Part tests confirm the high level of simulation quality for loading cases of practical relevance.
Novel Exterior Plasma Coating System Using a Stretch Blow Molding Module
Microwave induced plasma polymerization offers significant barrier improvement for PET bottles. This is essential to extend shelf life of sensitive beverages like beer especially in small bottles. For using the plasma process to coat the exterior of bottles a novel reactor concept is presented which proves to be highly suitable for industrial implementation.
Process-Simulation of Compression Moulding Compounds
This paper presents a flow model considering shear- and elongational viscosity as well as wall slipping effects of fibre-reinforced compression moulding compounds (SMC, GMT, LFT). The advantages compared to commonly used models are the improved computation of the pressing force and fibre orientation distribution.
Effect of Rheology and Die Design on Flow Balancing of Profile Extrusion Dies
A major challenge in profile extrusion die design is flow balancing at the die exit as an unbalanced flow causes distortion of the profile. This is especially true for complicated profile dies with uneven thicknesses in certain sections of the die. In this work, we demonstrate the use of a factorial statistical design of numerical experiments to study the effect of geometrical parameters and polymer shear thinning behavior on the optimum flow balancing of a profile die.
Function, Application and Handling of Hot Stamping Foils
Unlike many inks and coatings which can be somewhat “one dimensional”, hot stamping foils have multiple layers that perform different functions within the foil that contribute to a successful imprint or image. What makes this method of hot stamp decoration problematic is that any time one layer is changed it can have a direct affect on the outcome of a decoration. Without getting too technical we are going to address each layer and its contribution to the decoration of a plastic part.
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