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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Via two-step solid-state foaming using subcritical CO2 as blowing agent, the foamed acrylonitrile-butadiene-styrene/carbon fibers (ABS/CFs) composites are prepared. The results demonstrate that a bimodal cell structure (BMCS) is developed in the foamed ABS/CFs composites. Small and denser cells are developed in the ABS matrix, whereas large cells are formed around the CFs due to concentrated CO2 at the ABS-CFs interfaces. The mean cell diameters are 0.39–0.92 μm for the small cells and 12.5–25.6 μm for the large cells, being dependent on the CFs content. The CFs especially at 10 wt% or higher can refine the small cells via both increasing the strength and elasticity of the ABS matrix and restricting their growth under large cell growth. Interestingly, slow depressurization for the saturated composites followed by foaming is also favorable to refine the small cells, which is mainly attributed to no cells to be preformed in the saturated composite via the slow depressurization. Relatively higher saturation pressure or modest foaming temperature can further refine the BMCS in the foamed ABS/CFs composites.
Hsiang-Liang Lin, Li-Hsuan Shen, Chih-Chung Hsu, Rong-Yeu Chang, June 2022
Nonlinear warpage analysis which considers different kinds of nonlinearity effects has attracted more and more attention recently, especially in the automotive industry. This study is mainly aimed at using the new functions in Moldex3D, “Nonlinear warp analysis” and “Buckling analysis”, to predict the warpage of the products. These new solvers cooperate with the temperature distribution and the residual stress caused by the phase change from the manufacturing process and predict the deformation of the product considering the geometric characteristic and process conditions.
Joel Thambi, Vamsy Godthi, Marco Nefs, Nadia Grossiord, Jongwoo Lee, June 2022
Multi-Layer extrusion (MLE) is an advanced co-extrusion processing technology, which enables two polymer systems to be melt extruded, combined in an alternating format to very small total thickness <100μm and arranged in higher number of layer typically ranging from 8 to 1024. The focus of this paper is to investigate polymeric materials which are high modulus (e.g. LNP™ EXL PC copolymer or polymethyl methacrylate PMMA) and relatively low modulus (e.g. TPU) in nature as an alternating material combination for MLE. By combining different modulus of polymeric materials in MLE films, it is possible to achieve desired balance of different properties like mechanical, thermal, optical, dielectric etc., by synergistically combining the properties of the individual resins. In this paper flexural test is shown as an example to discuss the mechanical performance of MLE films. One of the major challenges of the MLE process is the down-selection of materials that are thermoplastics and have “matching” viscoelasticity at the processing temperature, as assessed by viscosity measurement at lower shear rates. Additionally, in order to ensure inter-layer adhesion, solubility parameters and processing windows of the two resins must be considered. In this study differences in adhesion were noted between PC/PU and PMMA/TPU MLE system. In PMMA/TPU MLE modification of processing temperature resulted in an improved interfacial stability and interlayer adhesion.
Due to the recent and ongoing pandemic – COVID-19 – there was an urgency to determine a method to delay the continuously rapid development of the new virus. As a result, Ultraviolet-C (UVC) light, also known as Ultraviolet Germicidal Irradiation (UVGI), has been in higher demand because of its known ability to disinfect quickly and effectively. However, because of its short wavelength/higher energy, either 222nm or 254nm, material degradation is usually much more accelerated than Ultraviolet-A (UVA) or Ultraviolet-B (UVB). At this moment, this study only observed color change when exposing polystyrene to UVC light, and it is believed that this is one of the first studies, if not the first, conducted with this material. Polystyrene was selected because of its availability, abundance of relevant research (ie. UVA/UVB exposure results), and its use in weathering standards. Additionally, since there are no standards specifically about UVC exposure, this preliminary research may provide some direction.
Thermoplastic polyolefins (TPOs) have been widely utilized in a variety of automotive applications. Most importantly, the TPOs used in interior and exterior parts in automotive applications require aesthetics and good mechanical properties simultaneously. Among many of the inorganic fillers, talc is an inexpensive and natural mineral, which has the platelet structure with individual layers holding together by week Vander Waals forces. This distinct layer structure can be delaminated at low shear forces to easily disperse in TPOs. Additionally, the talc particle size can be manipulated by the various micronizing processes. In this research, talc-reinforced polypropylene (PP) systems as a set of model systems have been chosen to investigate how the particle size and surface treatment of talc influence the TPO fundamental scratch and fracture behaviors.
Mostafa M. Pasha, Kyehwan Lee, Heinrich Foltz, Jesus Valladares, June 2022
Injection molding is one of the most popular techniques for global plastic production. With this automation technique, the plastic products can be manufactured at low cost with a complex geometrical shape. A manufacturing process with high productivity of an injection molding machine depends on optimized injection molding parameters. Injection molding pressure and temperature inside the mold cavity are the most critical parameters. However, cavity pressure transfer is not used due to cost and maintenance issues. During this research, an experimental procedure is performed to determine a process monitoring system using asynchronous data acquisition, through the incorporation of a wired piezo-ceramic sensor to acquire pressure of the injection molding system. This piezoelectric sensor is designed in such a way that, a Bluetooth device can be connected with a sensor and can take live data reading of parameters from the running molding machine.
Jinlei Li, David J. W. Lawton, Guerino G. Sacripante, Michael R. Thompson, June 2022
Processes needing to extrude biopolymers can be challenged by the poor flow properties often exhibited by this class of materials. Lignocellulose is one such material that is very attractive to the future polymer industry as a potential engineered biopolymer suitable for structural applications. To convert the poorly processable lignocellulose pulp into a flowable thermoplastic, the chemistry of both cellulose and lignin need to be modified, and to do so economically, attention is turned towards reactive extrusion. A reactive solution is required for the modification but also, to simply allow the lignocellulose to flow through the extruder. This study examines the novel idea of a recycle stream in reactive extrusion to reduce the normally high concentration of reactive solution needed. The goal behind the recycle stream was to produce an exiting product requiring minimal recovery of the unreacted solution without the introduction of a contaminant into the process to aid lignocellulose flow. The results showed that a comparable thermoplastic product could be produced with ~50% less reactive solution by recycling 25% of the exit stream back into the process, The recycled polymer was an effective plasticizer for the lignocellulose pulp, lowering the reliance on the reactive solution to offer this function in addition to acting as the modifier.
Min-Seok Choi, HyeongJu Lee, Ilhyun Kim, Byoung-Ho Choi, June 2022
High density polyethylene (HDPE) is one of the most widely used materials in the pipe industry because of its several advantages such as low price, excellent productivity, light weight and high resistance to chemical degradation. For potable water pipes, their lifespans are supposed to be over 50 years, so it is essential to check their long-term performance in certain service conditions. The point is that potable water contains disinfectants including chlorine or chlorine dioxide which shortens the service time of water pipes. In addition to disinfectant, environmental conditions like internal pressure and temperature of media inside also cause deterioration of properties of plastic pipes. To understand the degradation mechanism by potable water, we focused on two parameters, the concentration of disinfectant and the temperature of the solution. In this study, specimens obtained from HDPE pipes were artificially degraded in 5 different kinds of chlorine dioxide solutions with various concentrations and temperatures. Micro-tensile tests were conducted to study the variation of mechanical properties of HDPE specimens. The Fourier transform infrared (FTIR) spectrometry and the gel permeation chromatography (GPC) analysis were also conducted to study the variation of chemical properties of HDPE according to exposure time to chlorine dioxide solutions.
Peng Zhao, Jun Xie, Yuhan Jia, Lih-Sheng Turng, June 2022
Standard magnetic levitation (MagLev) device consists of two identical square permanent magnets with like poles facing each other. Limited by the size of the permanent magnet, standard MagLev device cannot levitate samples with large size. This paper proposed a novel MagLev device using magnet arrays, which can accommodate large-scale samples. Unlike magnet arrays in previous studies, all magnets employed herein face the same direction. The magnetic field generated by the magnet arrays is similar to that of the standard magnet. Within the magnetic field induced by the magnet arrays, the polymer can be levitated to an equilibrium position in a paramagnetic solution and the levitation height is related to its density. The equation correlating density and levitation height can be obtained according to the simulation results. Solutions of different concentrations were used to measure densities of a variety of polymers with an accuracy of ±0.0003 g/cm3. The non-destructive testing could also be used for plastic parts based on its posture (orientation) within the paramagnetic solution. The use of magnet arrays circumvents the trouble of manufacturing large magnets, realizes testing of polymers/parts with large sizes, and facilitates industrialization of magnetic levitation detection.
Praveenkumar Boopalachandran, Jörg Theuerkauf, Alexander Williamson, Jorge Gomes, Avery Brown, June 2022
The overall goal of the project targets the development of a product containing a rheology modifier additive in polyethylene (PE). This product is being sold to film converters for addition to the extruders of blown-film lines together with LLDPE resins. This increases the melt-strength during processing and the shrink tension for collation shrink films, enabling reduction in LDPE content and resultant tougher films. A tougher film will allow down-gauging and hence reduce material consumption, increasing the sustainability component for customers. This study focuses on the development of an analytical method at Dow to measure the concentration of the rheology modifier additive in PE. The method was validated and implemented successfully.
Puneet Garg, Zbigniew Stachurski, David Nisbet, Antonio Tricoli, June 2022
Advances in nanotechnology and surface sciences have necessitated superior polymeric coatings with novel applications. Urethane-acrylate-based interpenetrating polymer networks are one such class of ultra-tough polymers being researched actively for their wide-ranging applications from bullet-proof vests to binders for super dewetting coatings. Urethane-based systems are well-known for undergoing side reactions which could result in instability of colloidal suspensions engendering gelation resulting in significantly reduced shelf life of synthesized formulations and coating inconsistencies over time. Consequently, it becomes crucial to examine and control the factors inducing gelation. In this study, we investigate two approaches to prevent the gelation of colloidal urethane-based suspensions. In the first approach, we tune the NCO:OH ratio, and in the second approach, urea groups were formed in the presence of water. It was observed that both approaches resulted in storage stable colloidal suspensions with more than six months of shelf life. Durability assessment of coatings however indicated that urea-containing formulation resulted in notably robust coatings as compared to NCO:OH tuned coatings which can be attributed to the presence of strong hydrogen bonding arising from bifurcated hydrogens of urea.
Royan J. D’Mello, Shardul Panwar, Anthony M. Waas, Umesh Gandhi, June 2022
The extraction of cure-dependent fatigue behavior under tension-tension fatigue is presented for filament-wound coupons. Displacement controlled fatigue tests are performed on tubular filament-wound coupons. The state of the tube is characterized by performing interrupted static tests in between the fatigue cycles. At the coupon level, the state of damage in the matrix is obtained using micromechanics expressions with the help of Digital Image Correlation (DIC) technique. The results show a noticeable difference between fully cured (95%) and 80% cured composite specimens.
Ruben Schlutter, Alexander Paskowski, Manuel Schneider, Rainer Jahn, Joshua Voll, Thomas Seul, Andreas Wenzel, Gerd Telljohann, June 2022
Foamed parts are being produced in ever greater quantities. This is done, on the one hand, to save weight and, on the other hand, to take advantage of the greater design freedom in the layout of foamed components. Until now, quality control of the foam structure has hardly been possible without destructive testing methods. Therefore, a test method is presented to qualitatively evaluate the foam structure of foamed components without destruction.
Samuel R. Swan, Claudia C. Creighton, Russell J. Varley, James M. Griffin, Bekim V. Gashi, Sayed Mohsen Seraji, June 2022
This work explores the effect of core shell rubber (CSR) addition on the resulting properties of a highly crosslinked bi-component epoxy resin blend. The effects of network structure and topology are explored and related to the efficacy of CSR as a toughener for rigid, high-Tg polymer networks. A combination of thermal, spectral, and mechanical testing shows that excellent toughness enhancement can indeed still be achieved, despite a modest reduction in flexural properties for a high glass transition temperature (~259°C) network.
Nanocellular foam has attracted significant attention because of its superior physical and mechanical properties than microcellular foams. In this study, nanocellular foams were produced using the hot-bath and hot-press foaming methods. By lowering the saturation temperature (Tsat) to -30 ºC, the CO2 solubility was increased to 45.6%, and the cell size was reduced to less than 40 nm. Samples prepared by hot-bath exhibited smaller cell size, thinner solid skin, and transitional layer.
Sumit Khatri, Shuang Xiao, Hung-Jue Sue, Xing Cheng, June 2022
Polymers are inherently scratch sensitive due to their soft nature. Utilizing patterned surfaces while retaining transparency is a viable strategy to achieve better scratch performance. In this paper, we model the scratch behavior of micro-patterned surfaces using FEM simulation by employing a powerful coupled Eulerian-Lagrangian approach. The effect of two different pattern types on scratch behavior is studied and validated with available experimental results. Results suggest the significance of patterned surface topology in improving scratch performance.
Ruiyan Zhang, Eric S. Kim, Sandra Romero-Diez, Patrick C. Lee, June 2022
In the effort to alleviate climate change and energy consumption issues, thermally insulating polymeric foams can improve energy-management efficiency. we report a superior thermal insulation (~28.5 mW⋅m-1K-1) microcellular foam from ethylene-norbornene (NB) based cyclic olefin copolymers (COCs). Unlike the traditional carbon-filled approach, the incorporation of more NB segments (content from 33, 36, 51 and 58 mol %) in the COC structure greatly improved its ability to block thermal radiation without increasing its solid thermal conductivity. Using the supercritical CO2 and n-butane as physical blowing agents, we fabricated COC foams with tunable morphology. The void fraction of the foams ranged from 50 to 92%, and they demonstrated a high degree of closed cell content (>98%). In COC foams with given cellular structures (e.g. void fraction of 90%, cell size of 100–200 μm and cell density of ~107 cells/cc), their total thermal conductivity decreases from 49.6 to 37.9 mW⋅m-1K-1 with increasing NB content from 33 to 58%, which is attributed to high- NB COC’s strong ability to attenuate thermal radiation.
Vanessa Frettloeh, Udo Hinzpeter, Jan Pfeiffer, Christian Kolbe, Udo Staps, Felix Gemse, Simon Jahn,, June 2022
Due to rising demands on the quality of the final plastic product, it becomes increasingly important to influence the thermal behavior of the injection molding tools. Due to this fact the geometry of heat control channels becomes very complex, leading to a change in the manufacturing strategy of large-scale tools: manufacturing of a layered structure followed by joining the complete component. Besides the influence of the surface roughness and precision of the mold making the possibility of joining non-planar surfaces is elucidated. To demonstrate and to evaluate the diffusion bonding process, a demonstrator injection-molding tool was constructed and realized by joining the nozzle side and the ejector site of the mold by diffusion bonding after the contour conformal cooling channels were integrated. The cycle time for the production of fan wheels with the finalized mold could be reduced by 10%. Moreover, the concentricity of the fan wheels could be improved.
Yannick Bernhardt, Marc Kreutzbruck, Ruben Czichos, Jörg Dittmann, Peter Middendorf, June 2022
The material properties of fiber reinforced plastics are highly directional and the final fiber orientation can usually only be determined after the manufacturing process by time-consuming and cost-intensive sample preparation. The determination of the mechanical properties usually requires destructive testing. Compared to conventional methods, the method of ultrasonic birefringence presented here allows a non-destructive determination of the shear moduli G13 and G23. Furthermore, it allows the determination of the fiber orientation without the need of a complex specimen preparation. The difference in shear modulus measurement between the two methods is less than 1%.
The purpose of this research is to develop measurement devices and verify whether the permeability values obtained by different experimental devices and theoretical models are correct through Moldex3D RTM simulation tool. The experimental mold dimension and process parameters are established in Moldex3D for verification, such as one-dimensional flow and radial flow. From the results, it is known that the experimental and simulation results are highly consistent. Therefore, Moldex3D simulation software can be used as a verification tool to compare the permeability and flow front.
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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.
"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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