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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Packaging seals must be both easily opened and strong enough to maintain integrity. To tailor the strength of Ethylene Vinyl Acetate (EVA) seal layers, Polybutylene (PB-1) is often added. This study examines the effects of seal layer composition, gauge, and sealing temperature on seal strength. A composition and structure/property map for EVA/PB-1 sealant layers was developed. This work helps provide an understanding of material origins of seal strength, so that strength may be easily tailored.
In conjunction with UV technology, a fluid energy mill (FEM) was demonstrated to simultaneously and in-situ achieve several functions, namely: size reduction of pre-coated coarse micron-sized particles with UV-curable chemicals into smaller (ca. 1~10?m) particles, coating of UV chemicals onto the milled particles, and curing of the UV chemicals. IR analysis showed that the double bond conversion was up to 71% and 93% using air and nitrogen as motive gas, respectively.
This investigation focuses on understanding the effects of particle size and surface area of cryogenically- ground micronized rubber powders (MRP) on the properties of MRP/polypropylene (PP) composites. Comparisons are made with ambient-ground rubber powders and its PP composites. The morphology of the fracture surfaces of the composites is studied in relation to the effects of particle size on mechanical properties. In addition, this paper discusses utilizing a compatibilizer with MRP in improving the mechanical performance of the PP composites for its use in various market segments, such as automotive, consumer and, construction.
Solid-state shear pulverization is a unique, emerging processing technique for mechanochemical modification of polymers, compatibilization of polymer blends, and exfoliation and dispersion of fillers in polymer composites. The instrumentation is a modified twin-screw extruder, where the barrels are continuously cooled below the transition temperatures of polymers. Using a model system of neat polypropylene, the effects of various processing parameters, such as barrel dimensions and temperature, screw design, and material feed rate, are correlated to output morphology, structure and properties.
The prediction of the pressure drop gradient and the evaluation of the drag reduction phenomenon observed during the piping multiphase flow of a Carbopol/Air mixture have been investigated. Viscous flow tests in rotational rheometers and pressure drop measurements in pipe lines have been carried out with both smooth and rough surfaces. The Power law model is used to predict the pressure drop gradient. The pressure drop gradient in the intermittent multiphase flow regimes can be predicted by modifying the classical approach of Lockhart and Martinelli with an empirical correction factor. An Empirical model with quadratic equation has been proposed to describe the experimental evolution of drag ratio as a function of Re'L / Re'TP.
Micronized Rubber Powder (MRP) is classified as dry, powdered elastomer in which a significant proportion of particles are less than 100 microns. It is used as a compound extender to offset the spiraling prices of natural and synthetic virgin rubber materials. MRP is typically made from cured elastomer feedstock via a cryogenic process at a temperature below the Tg of the polymer. A better understanding of MRP surface properties is needed to facilitate efforts to utilize the material as a high value, sustainable material for use in various industrial and consumer rubber products. An update on MRP characterization is presented, including surface morphology by SEM, surface chemistry by XPS, surface area by Kr BET, and particle size distribution by laser diffraction. An example is given that demonstrates how the surface chemistry can be used to explain the effect of MRP on cure and physical properties in rubber compounds.
A new class of thermoplastic reinforcements was recently developed using technology whereby carbon nanostructures (CNS) are grown on the surface of glass fibers. This hybrid reinforcement results in specialized, multifunctional thermoplastic compounds that exhibit 60 dB of electromagnetic interference (EMI) shielding. This paper will discuss the recent research that has been conducted in incorporating the carbon nanostructure/glass fiber hybrid into polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) and polyamide-6,6 (PA-6,6) and give a highlight of the material properties of the resulting compounds.
Sizing is applied to carbon and glass fiber during manufacturing to protect the fiber during and after production, impart processability, enable composite fabrication and provide interfacial adhesion between the fiber and matrix resin. If the sizing’s only function was to improve processability then it would be possible for one sizing to “fit all”, however interfacial adhesion is critical and for every matrix resin a different sizing chemistry is required. This presentation will provide an overview of sizing chemistries available and examples of their impact on processing and mechanical properties.
Establishing meaningful and reliable flame, smoke and toxicity (FST) requirements for aircraft and train components made from engineering thermoplastics is an ever-evolving task for the mass transit authorities throughout the globe. This paper attempts to clarify the current state of the US and EU regulations, the associated test methods and typical FST performance of the polymeric materials used today in the mass transit markets. Pending improvements to current FST requirements by the US FAA and the EU EASA regulating bodies, including provisions for heat release and smoke density, are also discussed.
The viscoelastic behaviour of a number of commercial and newly synthesized linear biodegradable polyesters - poly (?-caprolactone) (PCLs) with different molecular characteristics was investigated using both rotational and capillary rheometry. The variation of the zero-shear viscosity and relaxation spectrum with molecular weight was studied in detail. The PCL processing instabilities were studied by capillary extrusion using a number of capillary dies having various diameter and length-to- diameter ratios. Sharkskin and gross melt fracture was observed at different shear rates depending on the molecular characteristics of the resins and the geometrical details of the capillary dies.
Pigment loading level is one of the most critical factors, governing the properties of the injection molded components. Changing the ratio of the pigment (Colorant) to the base resin could result in failure of the molded component. Material characterization such as Thermo Gravimetric Analysis (TGA) can be conducted to determine the pigment loading level and correlate the failure with functional characteristics of the molded component. Higher concentration of the pigment results in loosing mechanical property of the plastic and thus resulting failure during end use of the product.
The process simulation of thermoset molding processes (e.g. transfer molding, liquid injection molding) becomes increasingly important, because it can significantly reduce the cost of product development. This demands the correct determination of heat transfer and rheological coefficients. The aim of this study was the designing and construction of an apparatus which can measure the thermal contact resistance and thermal conductivity of epoxy molding compounds in the same circumstances which they encounter during processing.
The objective of this study is to find an optimal design of electromagnetic induction coil for mold surface heating. To simulate the temperature distribution of mold surface in the induction heating process, the commercial software of COMSOL Multiphysics is employed. Design parameters such as induction coils include coil diameter, heating distance, coil space, and electromagnetic induction frequency are considered in this research. The Taguchi method is used to analysis the effects of process parameters on the mold surface temperature distribution and heating rate. The simulation shows that: (1) coil diameter and coil space are the most significant parameters of affecting heating rate and temperature uniformity. (2) Small coil diameter increases the heating rate but results in non-uniform heating temperature. (3) Short heating distance is helpful for the heating rate but creates worse temperature variation. (4) Small coil space results in fast heating rate but generates significant temperature difference. (5) High induction frequency facilitates heating rate.
Thermal analytical techniques that are used to characterize nanocomposite formulations. Differential Scanning Calorimetry (DSC, HyperDSC™), Thermogravimetry (TGA), Dynamic Mechanical Analysis (DMA), and the hyphenated technique Thermogravimetry-Gas Chromatography-Mass Spectrometry (TGA-GC-MS), are used to measure nanocomposites. These measurements help ensure that the nanocomposite manufacturing process is stable, reproducible, and reliable. This poster concentrates on the formulation and end product validation through Differential Scanning Calorimetry (HyperDSC™) characterization of the rigid and mobile amorphous fractions of a nanocomposite.
This paper presents the tensile properties of ABS parts fabricated by Fused Deposition Modeling rapid prototyping process. The mechanical behavior of FDM processed ABS parts for engineering applications is dictated by the FDM process parameters. This paper characterizes the tensile properties of ABS parts considering process parameters such as air gap, raster width, raster angle and build orientations. The tensile properties of FDM processed ABS parts are compared with that of injection molded ABS parts.
Nylon 6 (polycaprolactam) is a polyamide that is widely used in the form of fibers. There are two crystalline forms, ? and ?. The common ? form has a fully extended planar zigzag conformation. The ? form differs in the hydrogen bonding between chains which produces a twisted gauche conformation about the C-N bond of the amide group. This change in conformation leads to significant differences in the Raman spectra of the two forms. The crystallization behavior of nylon-6 is known to differ between virgin and previously extruded material. DSC measurements show that crystallization from the melt occurs at about 173°C for virgin material but at about 185°C for samples that have previously been extruded. Combined Raman and DSC measurements provide different insights into thermally induced phase changes. In the case of semi-crystalline materials Ramandata gives qualitative information about molecular conformations to complement the purely quantitative information from DSC. We have used this approach to study crystallization in nylon-6.
The co-rotating fully intermeshing twin-screw extruder is the primary production unit for compounding of polymer based materials. It also has had a long term presence in processing material in the chemical and food industry and more recently in pharmaceuticals. While this equipment celebrated its 50th anniversary several years ago and might be considered a “mature” technology, it has not experienced a decline in new developments as might be expected, but rather a significant number of advancements continue to evolve. This paper will highlight several significant developments of the past 10 to 15 years. These are the implementation of high torque (power) designs, the use of increased rpm in conjunction with high torque for improved operating flexibility and productivity, and finally a technology breakthrough for feeding difficult to handle low bulk density materials.
This study investigated the effect of surface modification of nanoclays on the compatibility of Maleic Anhydride-grafted polypropylene (PP-g-MA)/poly (ethylene oxide) (PEO) blends. Rheological testing confirmed the network formation of nanaoclays of all types. SEM confirmed the emulsifying role of nanoclays by reducing the PEO domain size. For the case of using dialkyl (C18)-modified nanoclays, mechanical testing showed that the elastic modulus and the toughness were respectively improved by 20% and 55% compared to unfilled samples.
To obtain information on the temperature dependence of the interfacial strength (IFSS) in glass – polypropylene composites a thermomechanical analyser was adapted to enable microbond testing to be carried out in a well controlled temperature environment. Test results obtained by TMA-microbond testing showed excellent comparability with those obtained by normal microbond testing. The of IFSS of glass – polypropylene was measured from -40°C up to 100°C. The IFSS showed a highly significant inverse dependence on testing temperature.
Environmental stress cracking (ESC) resistance has become an essential industrial criterion for engineering thermoplastics, as ESC causes unexpected brittle fracture of ductile amorphous plastics. In the automotive industry, a variety of amorphous plastics are used, which need to be ESC resistant, as they come in contact with various fluids while subjected to mechanical stresses. PC-ABS materials offer a good compromise between processibility, cost and mechanical properties. However, this material is prone to ESC failure.
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Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
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