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.
The SPE Library is just one of the great benefits of being an SPE member! Are you taking advantage of all of your SPE Benefits?
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.
Stress-induced crystallization in PolypropylenePierre Donaldson and Thoi Ho (Flint Hills Resources)Abstract:Conventional method to induce crystallization in Polypropylene is the use of external nucleators such as Sodium Benzoate and other organic salts. Several recent studies have also shown the phenomenon of flow-induced crystallization in absence of an external nucleator. Extensional rheometers and high intensity mixers have been used to produce such flow-induced crystallization. We have found that an increase in crystallization temperature for Polypropylene can also be achieved by extrusion through twin-screw extruder. Effect of such nucleation on subsequent fabrication process, e.g. injection molding and resulting mechanical properties were studied. WAXS studies showed 10% increase in crystallinity. In comparison, external nucleation shows and increase of 45% crystallinity. Increased in crystallinity was due to increase in form. The effectiveness of different methods to induce crystallization will also be discussed.
One major problematic to solve with multi-walled carbon nanotubes (MWCNTs) is the control of their process of dispersion in order to avoid agglomerates. This challenge is even more difficult if the host matrix is non-polar. This work focuses on the study of processing parameters to efficiently disperse MWCNTs in polypropylene with two different approaches: direct compounding and masterbatch dilution. The relationship of achieved results of dispersion and electrical performances with the variation of processing parameters will be determined through measured electrical resistivity, agglomerate area ratio and specific mechanical energy calculations.
Composite materials are made by combining two or more materials. In terms of achieving new and unique properties composite materials are one of the commonly use method. Polymeric composite materials consist of polymer matrix and fillers. Here the selected polymer is Acrylonitrile Butadiene Styrene (ABS) as the matrix and mica as the filler. ABS is one of the versatile plastics with high melting point, hardness and strength. ABS is used in making car bumpers, motorcycle helmets, musical instruments, golf clubs, and more. Mica is unique plastic filler in terms of mechanical, thermal, chemical and electrical properties. Because of these good properties, mica is widely used as an additive mixed with nearly all types of plastics such as PP, HDPE, PET, etc. Mixing ABS with mica will prepare products which are better in quality and higher in properties of the existing one which is made with ABS alone. ABS plastics and mica filler with different concentrations were mixed by using an internal mixer. The mixed materials are shaped into standard specimens through injection molding machine. The prepared composites were tested for structural, mechanical and thermal properties.
This paper attempts to optimize the additive package for stabilization of glass filled polypropylene by a comprehensive design of experiment and subsequent regression analysis. Thermoplastic materials are processed at high temperature and high shear. A product’s lifetime exposure to heat, sun light, and humidity cause severe degradation in physical performance and discoloration. Suitable additives, such as heat stabilizers, antioxidants, processing aid and light stabilizers are added to improve the long-term performance. In this study, principles of mixture design of experiment and subsequent statistical optimization of additive packages for a fiber glass filled polypropylene (PP) has been performed using Minitab® to analyze the results. Responses are considered individually to understand the synergism and antagonism that exist within additives. Two anti-oxidants (AOs), two ultraviolet light (UV) stabilizers, an acid neutralizer (AN) and lubricant (L) were evaluated. Combinations of anti-oxidants (AOs) and UV stabilizers support the retention of physical properties and help reduce yellowness after hot air ageing at 150oC up to 1000 hours. The objective of this study is to analyze the properties of tensile stress at yield, tensile strain at yield, tensile modulus, notched Charpy and yellowness index. This study also evaluates the effects of projected component levels to achieve target physical properties.
With standard Carbon Black, it is difficult to produce compounds with both very high jetness and outstanding mechanical properties at the same time. Therefore, in a first step, we worked on our mechanical dispersion process and achieved strong improvements on jetness and mechanical properties. In a second step, we optimized our particle's morphology to get even better color and dispersion, resulting in further improved results. Summarized, by combining process and particle innovations, mechanical performance can be increased by up to 54% at same jetness level. Depending on the application's needs, jetness can also be increased by up to 65%. Balancing jetness and mechanicals to an optimal combination is possible by adjusting the carbon black loading.
Our goal is to simultaneously improve fracture toughness and biodegradation behavior of poly(lactic acid) (PLA) using the same additive. Our approach explores the use of encapsulation on a series of degradation-promoting additives so that they may survive the melt extrusion process while limiting any breakdown of the matrix. In addition to promoting biodegradation such encapsulated particles are designed to enhance toughening. Such dual use particles have the potential to broaden the uses of PLA. In this work, particle properties, structure and dispersion in PLA are examined and the accompanying tensile behavior investigated. Particles with polysaccharide or protein shells with oil cores were able to be produced and dispersed within the PLA matrix with minimal leakage of the active material during extrusion to 3D printer filament. The elongation at break and yield strength were improved over neat PLA.
Four different soy additives were compounded into Linear Low Density Polyethylene (LLDPE). The four different additives were compounded and pelletized by FKuR. After a film was produced for each of the four batches, the mechanical, barrier, and thermal properties of each batch was characterized and compared to a control sample. The use of soy in polymeric films improved mechanical properties in LLDPE, reduced the cost and amount of plastic used, and improved water vapor barrier of the polymer. The modulus of each film increased with the use of filler. However, the ultimate extension and ultimate tensile strength decreased in the samples containing soy fillers. The films showed increased crystallinity in samples containing soy fillers. Additionally, thermal analysis indicated large amounts of weight loss in the soy loaded films when heated.
Kruger Biomaterials proprietary cellulose FiloCell™ is obtained from peeling the filaments from wood fibres using a mechanical process that uses no chemicals or enzymes. Since the peeling is gentle, very thin filaments are obtained while the original length is preserved. The filaments are further surface treated without modification of the chemical structure in order to prevent hornification (agglomeration due to strong hydrogen bonds) and to produce 99.7% dried, re-dispersible filaments. The resulting filaments are renewable, non-toxic, have high surface area, high aspect ratio, mechanical strength and low density. Given these properties, cellulose filaments are a unique multifunctional lightweight filler which can be added to polymer resins as a reinforcing agent and can potentially replace glass fibers.In this work, cellulose filaments are melt-blended into thermoplastics LDPE, Nylon 6 and TPU. Cellulose filaments are shown to effectively increase the Young’s modulus and the strength of all polymer matrices. The mechanical enhancement is increased with loading level of cellulose filaments. It is shown that no compatibilizing agent is needed in order to improve the interaction between the hydrophilic filler and the hydrophobic matrix. Moreover, although one drawback of natural fiber is its thermal degradation at high processing temperature, we managed to successfully compound our cellulose filaments with nylon 6 which has a processing temperature of 230˚C. In LDPE resin, at the same weight, cellulose filaments outperform glass fibers in both tensile strength and tensile modulus. In comparison with other natural fibers, cellulose filaments have the advantage of higher mechanical performance and lower water absorption.
As part of an effort to develop light weight closures for carbonated soft drinks (CSD), a finite element model has been developed to understand the impact of resin properties and closure design on the end product performance. Phase I of the model development is to understand the deformation mechanics as a precursor to light-weighting effort. The model simulates typical loading conditions in CSD closures and predicts the resultant stress & strain in the closure. The current study focuses on the doming deflection of CSD closures. Preliminary results are in excellent agreement with the experimental results. The FEA results and experimental data suggest that viscoelasticity of the resin i.e. high density polyethylene (HDPE) plays an important role in determining the long term performance of CSD closures. The current report introduces the key techniques applied in the model development and summarizes the results of the model and the validation experiments.
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.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
If you need help with citations, visit www.citationmachine.net