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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Modeling Agglomerate Dispersion in Single Screw Extruders
We present a new model for assessing mixing in extrusion processes. The model combines numerical simulations of flow patterns in the extruder with a Monte Carlo method of clusters rupture and erosion mediated by the local fragmentation number. Particle size distributions and Shannon entropy are used for mixing characterization.
Structure-Property and Pigment/Organoclay Interaction in PP Nanocomposites
PP nanocomposites (PLN) were prepared by twinscrew mixing with organoclay and phthalocyanine blue pigment. Significant clay/pigment interaction was observed. Exfoliated organoclay exhibited carrier effect on the pigment. Pigmented PLN exhibited better mechanical properties than the unpigmented PLN.
Processing CNT/PVDP Composites for Enhanced Strength
The key to increasing the mechanical strength of a carbon nanotube (CNT)/polymer composite is to achieve uniform dispersion and alignment of the nanotubes in the polymer matrix. In this study, CNT dispersion and alignment were significantly improved by using a surfactant and a variety of unique processing steps to manufacture a 10wt% multi-walled carbon nanotube (MWNT)/ polyvinylidene fluoride (PVDF) composite. The resulting tensile strength of the composite was nearly double that of unreinforced PVDF.
Why Troubleshoot When You Can Prevent? A Bayesian Network Approach
Although successfully applied as a diagnostic tool to various fields, few Bayesian networks have been designed for prevention. Lack of time, personnel and resources have been obstacles for this branch of artificial intelligence. A method for constructing a Bayesian network based on established literature and practical knowledge of experts in the field is presented. The model will be applied to shear splay, incorporating factors in material, design and processing. Suggestions for implementation are also addressed.
Dynamic Vulcanisation of EPDM/HDPE-Based Thermoplastic Vulcanisates Studied Along the Extruder Axis
Dynamic vulcanisation of EPDM/HDPE blends with resol was studied in an extruder equipped with sampling devices. Upon complete melting of the HDPE pellets the blends reach quickly their final morphology. For the EPDM/HDPE (50/50; w/w) blend at transition from continuous via co-continuous to fully dispersed EPDM is observed, which is driven by complete HDPE melting and crosslinking. Crosslinking of the EPDM phase occurs already when the HDPE is not yet fully molten, but does not prevent phase inversion of the blend.
Cadence Copolyester Resins for Calendered Film
Eastman Chemical Company's Cadence Copolyesters are specially designed for calendering. Calendering is a process for the production of plastic film and sheet. Thickness ranges are typically .002- .030 and widths from 36-120". Production rates range from 1000-10000 pounds per hour. This process is predominantly used for flexible and rigid Polyvinyl Chloride. This unique combination with Cadence Copolyester resins provides the physical performance and attributes of the copolyester polymer with the efficiency and quality advantages of the calendering process."
Improving Weld Line Strength of Polycarbonate Acrylonitrile-Butadiene-Styrene (PC/ABS) Blends via Tailored Silicone Copolymers
Flame retardant PC/ABS blends with addition of tailored silicone copolymers exhibit improved weld line strength. The effect of copolymer architecture, impact modifier morphology and processing conditions on weld line characteristics is presented. These blends also show better flame resistance with UL94 ratings at thinner gages.
Polymer Replication and Characterization of a Ruled Diffraction Grating
The goal of this study was to process thermoplastic cyclo-olefin copolymer (COC) via injection micromolding and to evaluate its use for the production of diffraction gratings. The mold and the replicated gratings were characterized using atomic-force and scanning-electron microscopy. We statistically tested how well the replicas matched the mold. Our results show that molded COC is suitable for making diffraction gratings.
Micro and Nano Scale Solid-State PEI Foams
Polyetherimide by General Electric ( ULTEM 1000) was foamed by the solid-state process using CO2 in the subcritical range. At 5 MPa approximately 10 % CO2 by weight is dissolved in PEI. The rate of diffusion in 1.5 mm thick specimens changed when the gas pressure was lowered to 1 MPa , indicating that in this range of pressures the diffusion rate is dependent of gas concentration. Microcellular structures in PEI were obtained, with density reductions up to 45%. Nano-cellular foams, with cells in the 50-100 nm range, and with cell densities exceeding 1014 cells/cm3 were produced at 5 MPa gas saturation.
Thermoplastic Starch/Natural Rubber Based Nanocomposites
Novel nanocomposites with superior properties were made from thermoplastic starch-natural rubber blends using montmorillonite (MMT) nanoclay. The nanocomposites were prepared by melt processing, with natural rubber content varying from 9 to 21% by weight and clay content varying from 2 to 6%. Mechanical properties and water absorption of the thermoplastic starch became significantly better when natural rubber and clay were added. X-ray diffraction showed dispersion of clay in the polymer blends.
Thermal Properties of Polyethylene Nanocomposites based on Different Organoclays
In this work, alkyl pyridinium, imidazolium and phosphonium intercalants were used to produce organophilic clays with higher thermal stability than commercial alkyl ammonium modified montmorillonite. These organoclays were compounded with LLDPE and an appropriate compatibilizer using a micro twin-screw extruder. The degree of dispersion of the clay platelets was evaluated by X-ray diffraction (XRD). The thermal stability of the nanocomposites was evaluated by thermogravimetric analysis (TGA).
Investigation of Melting in a Single-Screw Extruder
Screw freezing experiments in a single-screw extruder were conducted for an ABS resin. The melting of ABS was also simulated by a full three-dimensional simulation of the two-phase flow in the compression section of the extruder. Numerical simulations as well as experiments exhibit the Maddock melting mechanism. However, numerical predictions and experimental data have some discrepancies, which are discussed.
Unique Atmospheric Plasma Surface Pre-Treatment Approach for Improving Adhesion
Three dimensional parts comprised of polyolefins such as polypropylene have low levels of polar functional groups on the surface and have poor wettability and adhesion properties, making it difficult to apply other functional layers such as dyes, inks, adhesives and coatings. To enhance surface polarity, surface treatments such as flame, corona or plasma can be applied to improve wettability and adhesion. Plasma can specifically be used as a preparatory treatment for the photografting approach recommended in this paper to achieve high stability in treatment and permanent changes to the surface.
The Extended Supply Chain and the New Economy
The extended supply chain represents an opportunity for improved products and services and as a source for new business models. This paper will explore the opportunities that exist for an enterprise when it understands the supply chain and its role in it. This is particularly important for materials and components suppliers in today's changing global economy.
Scale Up of Polypropylene Vis-Breaking for Industrial Application
A statistical experimental design was used to find the required concentration of a novel additive in order to obtain the same rheological behavior of higher priced, commercial controlled-rheology polypropylenes. A lab extruder was used to perform the experimental design, minimizing the amount of material needed. According to the results, recommendations were given to process two different lower priced polypropylenes with the additive in an industrial extruder with very good agreement with lab predictions.
A Multi-Sample Melt Micro-Rheometer
We have developed a multi-sample melt micro-rheometer (M3R) based on pressure driven channel flow and designed for simultaneous measurement of multiple polymer melts. viscosities The required sample size is between 50 mg and 100 mg. The driving force for the rheometer is pressurized gas from a nitrogen tank that forces polymer melt into a slit. The melt flow is monitored using a video camera that views the flow front through a sapphire window. The device contains no moving parts and no gaskets or O-rings. Measurements of polyethylene and polycarbonate are presented.
Effect of Environmental Stress Cracking Agents on, Fatigue and Creep of a MDPE Pipe
The effect of environmental liquids on slow crack propagation in MDPE pipe is investigated. At 50°C, the differences in kinetics and mechanism of crack propagation in fatigue and creep are described relative to that in air. The relationship between fatigue and creep was strongly affected by the presence of environmental liquids.
Flow Phenomena in an Intermeshing Twin-Screw Reactor/Devolatilizer
Using an extruder for a devolatilizer or condensation reactor requires balancing the mixing, degree of fill, residence time distribution, and vapor pressure drop effects. Various viscous fluids, rotor configurations, and operating conditions have been examined in a 100 mm diameter intermeshing corotating twin-screw extruder.
Plastic Pallet Design Improvement using a CAE Software
A CAE software was used to simulate the end-use load requirements of a plastic pallet. The simulation results indicated the critical areas of the part that need to be reinforced. Based on this, changes to the design were done using a CAD software until the functionality requirements were fulfilled while maintaining part appearance and ensuring low cost. Deformation results agreed relatively well with the actual deformations under extreme load conditions.
Effect of Shear Induced Flow Imbalance on Multi-Cavity Molds using Gas Assisted Injection Molding
This paper presents a study on the effect of shear induced flow imbalances on a thick flanged plate molded with gas assist. Samples were molded with and without melt rotation technology and the results contrasted. Flow imbalances and impact on gas distribution and gas penetration were analyzed. Melt rotation technology corrected the flow imbalances seen in multi-cavity tooling and helped gas penetration and distribution.
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