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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To overcome the competitive nature of stiffness and toughness, multi-layered structures are a potential solution. By using intelligent design criteria, it is possible to severely increase toughness while keeping the stiffness of the structure at a sufficiently high level. This method can be used for smart pipe-wall design in demanding applications. First multi-layer composites of pure and also highly reinforced thermoplastic materials have been produced and tested with regard to their toughness-increase. As expected, interface properties and mechanical property mismatch play a key role in the development of optimized structures.
Previous laboratory studies have shown that brittle cracks in Electrofusion sockets (E-sockets) typically initiate in the inner cold zone between the pipe and the socket and lead to brittle failure of the pipe connection. Therefore, a profound understanding of the slow crack growth (SCG) behavior is essential to predict an accurate lifetime for welded joints. Internal pressure tests (IPT) on E-sockets made of different PE grades were conducted to create brittle failure curves in a first test run and to investigate the characteristics of crack initiation and SCG by the use of additional optical analyses in a second test run. Based on these test results and by using a fracture mechanical material law for SCG for one of the investigated PE grades a model for the stress intensity factor KI characteristics in E-sockets at elevated temperature was developed by finite element methods (FEM). The current results demonstrate that a reliable prediction of minimum lifetime of E-sockets with the fracture mechanics approach is possible.
The resistance of polymer pipes in drinking water application against chlorine dioxide (ClO2) is crucial to ensure long-term functionality. The strong oxidative nature of ClO2 can cause an accelerated degradation of polyethylene (PE) resins and eventually shorten mainly the crack initiation time. To study the effect of ClO2 1 mm thick samples from six PE resins were subjected to exposure in 1 and 0.5 ppm ClO2 at 50 and 60 °C. Blank samples were also immersed in distillated water at 60 °C. Advanced material embrittlement with decreased elongation at break was observed in less than 5 weeks of exposure for each PE. Comparing the mechanical properties and the thermal stability various material performance was found. Furthermore unchanged properties of the blank samples point out the immense impact of ClO2 on the degradation of PE grades. The applied fast ranking methodology in terms of ClO2 resistance can serve as a valuable tool for material and stabilizer development.
Several investigations were undertaken involving polybutylene (PB) plumbing systems that had been in service for more than 20 years. A variety of tests were performed on the pipes, including ASTM test that were required for new PB pipe. Various PB pipe samples were submitted for analysis, including pipes from seven different locations around the U.S. The laboratory testing of the PB pipe samples included one or more of the following tests: a visual and microscopic inspection of the samples, dimensional measurements, quick burst testing, oxidation induction time testing, long-term hydrostatic pressure testing, and Fourier Transfer Infrared Spectroscopy (FTIR). The pipes analyzed did not reveal any significant degradation as a result of the long time service (>20 years) in hot and cold-water plumbing systems. This data was consistent with earlier investigations that showed that 18-year-old PB pipe still met the ASTM requirements for new pipe.
Flame retardant compounds serve an important purpose in society and are particularly critical in plastics, which are more flammable than other materials. To evaluate the efficacy of flame retardants in commercial products, it is important to know both the concentration and composition. However, due to the variability of flame retardants, the appropriate analytical method is not always obvious. In this publication, we analyze an unknown plastic box advertised to have flame retardant properties. We use a series of analytical techniques and evaluate their compatibility with one another.
The effect of biodegradable additive (Biosphere) on the spherulite growth rates of isotactic polypropylene was studied by means of polarized light microscopy. It has been found that the addition of biodegradable additive to isotactic polypropylene matrix increases the intensity of the spherulites at all covered isothermal crystallization temperature in the range from 125 to 145 oC. In comparison with the neat isotactic polypropylene spherulites, much smaller spherulites were obtained at all crystallization temperatures for the isotactic polypropylene/biodegradable composite. The obtained results show that the presence of the biodegradable additives enhances spherulite growth rate at low crystallization temperatures (below 135 oC) while the effect of these additives is almost negligible at high crystallization temperature (above 135 oC).
This communication presents comparative results between two separate techniques to accelerate physical aging in polymeric glasses: pressure conditioning and thermal annealing. Four different epoxy-based glassy thermosets were synthesized with specific molecular and network structures for further comparison and discussion. The epoxy compositions were synthesized to form glasses with comparable glass transitions but with different crosslink density and backbone stiffness. To analyze the glasses and the extent of aging, Differential Scanning Calorimetry was employed. Additionally, in order to perform the pressure conditioning, a pressurizable dilatometer was designed and built. The results show fundamentally different responses between thermal annealing and pressure conditioning. These differences are detailed and discussed.
Extrusion and injection molding of filled polymers are widely used in industry due to their high strength-to-weight ratios and for their ability to manufacture a variety of geometries while improving the overall mechanical properties. However, filler migration during processing is not fully understood. To gain an improved understanding of this phenomena, samples of polypropylene with different concentrations of glass beads were manufactured using the extrusion process, injection molding process and a screw-less extruder that was built in house. Computed Tomography scanning was performed on the samples to observe particle position and distribution after solidification.
Dow polyurethane (PU) business is investigating into cool comfort technologies for bedding products (pillows, mattresses), as it is a major driver in the market. Recently, there have been many enquiries around the commercial benchmark products (‘commercial product A’ and ‘commercial product B’) that sparked the interest for the Dow PU marketing team. There is an overwhelming interest to understand these materials and its composition. Analytical techniques utilized in this study for the deformulation of the two commercial products identified the presence of styrenic block copolymer (SEBS) as the major polymeric species. In addition, long chain aliphatics identified as mineral oil was observed in both products. Furthermore, a filler identified as talc was present in ‘commercial product B'.
Branching in polymers contributes many unique rheological properties in polymer processing. Polymer branching enhances chain entanglements, increases relaxation times, and increases the extensional flow viscosity as evidenced by the strain hardening phenomenon. For many years, researchers have used different rheological methods to quantify the degree of branching in polymer chains. The most commonly used rheological techniques for differentiating linear and long chain branched polymers include traditional small amplitude oscillatory shear testing (SAOS), such as frequency sweeps at multiple temperatures, followed by time-temperature superposition (TTS), extensional viscosity testing, and large amplitude oscillatory shear testing (LAOS). However, polymer chain entanglement and relaxation are not only affected by branching but also by molecular weight (Mw) and molecular weight distribution (MWD). The common rheological methods may not be able to distinguish whether the rheological property contributions are from long chain branching or Mw and MWD effects. In this paper, we describe commonly used melt rheological methods for studying polymer long chain branching and their respective benefits and limitations.
Evolved gas analysis improves the value of TGA data by allowing the identification of the chemical species evolved during decomposition. FTIR is particularly advantageous when organic molecules and IR active gases are being analyzed from the TGA sample. This lecture will introduce an innovatively designed TGA-FTIR and STA-FTIR (STA = Simultaneous DSC-TGA) for evolved gas analysis. The unique coupling system has the FTIR now mounted directly above the sample cell, eliminating the need for a long transfer line. The system allows immediate response from the FTIR when the sample loses mass. The lack of the transfer line allows for analysis of gas species that would ordinarily condense in a standard heated transfer line in addition to dramatically reducing bench space normally required for TGA-FTIR.
Poly(vinylidene fluoride) (PVDF) nanocomposites containing unmodified halloysite nanotubes (HNTs) are prepared by using extrusion with and without water injection. Transmission electron microscopy micrographs show that better HNTs dispersion is obtained in the PVDF matrix with water injection. The Halpin-Tsai equation is employed to quantitatively estimate the HNTs dispersion, indicating that the nanocomposites prepared with water injection possess large fitting aspect ratio of the HNTs owing to improved HNTs dispersion. The tensile fractured surfaces for the neat PVDF, P-Hm, and P-Hm-W samples exhibit different fractured morphologies, as evidenced by scanning electron microscopy, indicating that different fracture mechanism occurs. This is because the crystallization behavior of PVDF and the HNTs dispersion induced by injected water result in the formation of the voids, wedges, and ridges, and so cracks initially form at different locations.
In this paper, the task of image-based product classification is considered. This is a supervised learning problem where the input is an image of a polyethylene pellet and the output is a unique label attributed to the image from a finite set of labels corresponding to useful classes. This is a prevalent and highly relevant industrial challenge and recent developments in deep learning have proven to be successful in increasing the image classification accuracy. Thus, in this work, we leverage deep neural networks’ (DNN) ability to automatically learn features from images and test their performance in a real industrial context for describing the pellet shape. Furthermore, other machine learning techniques such as partial least squares discriminant analysis (PLS-DA) and random forests (RF) are also explored in order to assess the benefits of adopting DNN as opposed to current classifiers. PLS-DA, RF, and DNN models were developed for two classification tasks: pellet body shape classification (distinguishing good and bad pellets), and detecting tails in a pellet (distinguishing whether a pellet has tails or not). After developing these models, the results were consistent for both classification objectives: compared to the classification system currently in use, RF was able to better utilize the same pre-defined morphometric features and improve prediction accuracy significantly, while PLS-DA presented slightly better performance. DNN obtained the highest accuracy overall, with the advantage that there is no need to specify a priori which image features to use. Rather, they are directly extracted from the raw images.
In the study. PP/PTFE composites with different degree of fibrillation were prepared. Crystallization and rheology behavior was investigated. The presence of PTFE fiber enhanced the kinetics of isothermal crystallization of PP. The second modulus plateau at the low ω and a tan δ peak indicates the existence of a three dimensional networks. Extrusion foaming results shows that addition of PTFE increase a 2 orders increase in cell dencity and 10-fold decrease in expansion ratio due to addition of PTFE compared to that of PP. With PTFE nanofiber, open-cell content of the composites was increased.
In this work, we consider the effect of the addition of functionalized clay particles to a polyether based polyurethane that is a candidate to be used as for flexible storage containment for a variety military fuels. We have synthesized urethanes and fully incorporated functionalized layered silicate inorganic nanoclay with concentrations varying from 0% to 20% by weight. The clays were functionalized with polar hydroxyl groups (-OH) and nonpolar long alkyl chains (-CH3-(CH2)14-CH3) and we evaluated the transport properties of military grade fuels. We found the addition of the nonpolar alkyl functionalized nanoparticles, actually increased both the transport rate and the fuel solubility of the resultant composite.
Polyetheretherketone (PEEK) polymers are utilized in applications of extreme service environments in the oil and gas industry. However, their outstanding physical properties diminish after long-term exposure to highly concentrated ZnBr2 completion fluids under the extreme downhole conditions. PEEK is an insoluble polymer at room temperature and sparingly soluble at elevated temperatures in only a few special solvent mixtures. The research presented in this contribution is focused on detailed analytical studies to elucidate the molecular mechanisms that lead to the decomposition pathways during the degradation processes. This investigation includes determining the factors that hasten the polymer decomposition. Completion fluids composed of high concentrations of ZnBr2 and/or CaBr2 were applied to the long-term studies of the polymer at the continuous use temperature of 260 °C at a high pressure of 20 bar.The chemical changes of PEEK under the drilling conditions are visually obvious only when ZnBr2 completion fluids are applied. Since the PEEK polymer cannot be solubilized (which is needed for many analytical high resolution measurements) we chose to study the small molecules released during the PEEK treatment. Identification and quantification of the small molecules released into the completion fluid during the PEEK degradation could be achieved with solution NMR and the use of a calibrated standard. The identification was confirmed with other analytical techniques like mass spectrometry. Mechanistic studies based on the identification of the small molecules reveal the simultaneous occurrence of several decomposition pathways. For example, bromination by the ZnBr2 in the completion fluids, radical based decompositions, and hydrolysis under acidic conditions. The dominant reaction taking place in the PEEK polymer is C-C bond cleavage at the ketone group. The smaller molecules produced from this initial cleavage at the ketone are then degraded in a secondary process, for example, by hydrolysis. Finally, the degradation mechanisms found for PEEK were also established for another polymer with similar composition. Studying the chemically related polyetherketoneketone (PEKK) polymers in the described standardized manner, after exposure to identical conditions, led to the same decomposition pathways. Therefore, it is expected that future investigations of other polyaryletherketone (PAEK) polymers will reveal the same general degradation mechanisms as described for PEEK and PEKK in this contribution.
Internal structure is key to tailoring the performance of electrospun (ES) nanofibers. However, it still remains very challenging to characterize the structures inside ES fibers. In this study, ES polycarbonate (PC) nanofibers were successfully cut open along and across the fiber axis by embedding. These sections exhibited a clear core/shell-like structure, where the shell layer remained nearly con¬stant (50 nm or so) with increased fiber diameter, while the core layer showed a linear increase. The reason for this is discussed herein, and a model describing the variation of the core/shell layer thickness is proposed. This model has the potential to enable the production of nano¬fibers with superior properties.
The application of fast scanning chip calorimetry (FSC) for analysis of sheared polyamide 66 (PA 66) provided quantitative insight of the effect of shear flow and flow-induced formation of crystallization precursors/nuclei on the subsequent crystallization in a wide range of temperatures. In the high-temperature, heterogeneous-nucleation range, there is a direct relationship between the amount of specific work supplied to the melt and the acceleration of crystallization, presumably due in part to increased nucleation density of the sheared samples. This information is directly applicable to polymer engineering applications where the formation of crystalline domains during processing often occurs at rapid-cooling conditions. Analysis of the structure at the micrometer-length scale of sheared PA 66 by polarized-light optical microscopy (POM) revealed large shish-kebab structures.
The requirements of new and modern technical plastic are changing constantly. In most cases the required property profiles cannot be met by the polymers alone. For this reason, they are modified by a broad range of filling and reinforcing materials. High performance, functional fillers on the basis of needle-shaped wollastonite, platelet-shaped mica and platelet-shaped kaolin play a central role in this for many years. The mechanical properties are often modified with glass fibres. As fibreglass-reinforced moulding compounds are clearly anisotropic on account of the alignment of the fibres in the molten compound, they are not equally suitable for all components. The use of mineral fillers offers an interesting spectrum of new possibilities on account of their different specific features, such as morphology, hardness or surface condition. Furthermore, mineral fillers can be used also as nucleating agents or as supporter to enhance the flame resistance.Lately, new functionalities are required in addition to the traditional ones. Thermal conductivity of plastics is one of these new requirements: Electrical components with high energy density require an efficient dissipation of the heat incurred while maintaining the electrical insulation performance of the plastic material used. Thermal conductive plastics create a whole series of new kinds of applications with important advantages like straightforward mass production of complex components, e.g. injection molding or lightweight production. All important issues especially if we consider new applications in the E-Mobility area.The talk should give a general overview about fillers used in various polymers, with some examples in thermoplastics and thermoset resins, considering the topics mechanics, shrinkage and other specific modifications like increasing of the thermal conductivity and enhancement of flame resistance. As the event is some time away, we expect a quite broader range of results to be included in the lecture.
Light is responsible for our overall well-being and is a valuable source of energy for every person to an unlimited degree. Therefore, in modern architecture large transparent glass facades are used. In winter, the incident sunlight can so be used optimally. In summer, the sun often provides more heat than desired with negative effect on the indoor climate. During building design, the summer heat protection is therefore of central importance. The key challenge is to make best use of solar energy, while preventing indoor overheating.Conventional shading systems, whether internal or external, need complex assembly services, are expensive and often require intensive maintenance. Acrylic glass (PMMA), an affordable alternative to mineral glass, is widely used in construction and other applications. Common products in construction are especially solid sheets, multi-wall sheets and corrugated sheets.HPF The Mineral Engineers, a division of Quarzwerke Group, accepted the challenge and developed a whole new thermotrop additive. This new product was officially presented on the K-Show 2016 in Düsseldorf. This product is a masterbatch or an additive powder designed for acrylic glass. It is either homogeneously mixed with impact modified PMMA compounds or fed via dosing device during processing (extrusion or injection process). With this additive functionalized acrylic glass changes its transmittance of light and solar radiation as a function of the ambient temperature. When the temperature is increasing, on hot summer days for example, it switches from transparent state into a milky white state. This effect is adaptive and reversible, so the use of daylight and solar energy can be controlled.This presentation will show and explain the function and the effect of this new and innovative masterbatch and will point out how this new HPF product can solve some of the issues in the application area of daylight systems. The whole content is supported by investigation results and some application examples.
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Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
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ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
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