SPE Library
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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Conference Proceedings
Progress on Fiber Concentration for Injection Molding Simulation of Fiber Reinforced Thermoplastics
Mechanical properties of fiber-reinforced thermoplastic products have a deep dependence upon flow-induced variations in fiber structure, involving fiber orientation, fiber length, and fiber concentration. However, few numerical studies have been done on fiber concentration to date. Using the suspension balance model of particle migration, the objective of this work is to perform the concentration calculation in mold filling of a center-gated disk. Consequently, the predicted concentration distribution of short glass fiber filled polybutylene terephthalate (PBT) with an average volume fraction of 0.177, through the thickness measured at the lubrication region of the disk, agrees well with related experimental results.
Two-Time Dimensional Hybrid Dynamic Matrix Control for Injection Molding Process
Injection molding is a typical batch process that transforms polymer granules into various high-value-added products. The aim of this paper is to improve the batch process control performance in the two-dimensional (2D, within batch and batch to batch) and hybrid frameworks by exploring the repetitive and multi-phase nature of batch process. This research involves a 2D hybrid prediction model, comprised of a 2D step response model and a piecewise affine model. With this prediction model, a novel 2D hybrid dynamic matrix control strategy is proposed. Application to the injection molding process shows the effectiveness of the proposed control algorithm.
Automotive Prototype from Lignin and Nanocellulose Enhanced Polyurethane Foam: Bio Polyol vs Synthetic Polyol
Polyurethane (PU) foams were prepared using synthetic and bio-based polyol. In both cases, isocyanate content was reduced and cellulosic nanofibers and lignin were incorporated to achieve the desired rigidity. The experimental results indicated that the mechanical properties of 100% bio-based polyol PU foams exhibited higher performance compared to 100% synthetic polyol PU foam. The odor concentration of bio-based and synthetic PU foams showed in similar level. A automotive bumper energy absorber prototype has been developed from lignin and nanocellulose enhanced bio PU foams with reduced isocyanate content.
Sink Mark Shape Depending on Holding Pressure and Rapid Heat Cycle Molding – Mathematical Approximation and Key Parameters
The visibility and shape of sink marks is an important criterion for the quality of a variety of injection molded parts. Due to necessary geometrical features on technical parts, the formation of sink marks is mostly inevitable. The aim of this work is to present a study on the influence of processing conditions, especially rapid heat cycle molding (RHCM), on the sink mark geometry. Several process settings were tested for enabling the recognition of the most influential process parameters. The Pseudo-Voigt distribution model, a superposition of the Gaussian- and the Lorentz-distribution was found to deliver an accurate mathematical description of the sink mark cross-section shape. For this work, specimens were measured via confocal microscopy to gain the sink mark shapes. Two different sample geometries were used. This enables to investigate various base-to-rip-thickness ratios as well as the dependence on the flow-path length. By applying RHCM, the mold surface temperature could be introduced as important factor. The Pseudo-Voigt-Model was then fitted on the measured sink mark shapes, resulting in several fitting parameters. These fitting parameters were then correlated with the process settings. The results show strong correlation of both, holding pressure and mold surface temperature, on the sink mark topography.
Influence of the Flow Channel Geometry on the Degassing Pressure in Foam Extrusion
The onset of bubble formation or in other words the degassing pressure is an important value for the designing of a die for extrusion foaming. Therefore, the effect of flow channel geometry on the degassing pressure was examined with a newly developed slit die concept. The determination of the onset of bubble nucleation was carried out with an optical spectroscopy technique. In this study we used four different flow channel geometries to determine the degassing pressure for different flow conditions. Additionally simulation experiments were used to compare the different flow channel geometries in terms of shear rate, pressure drop rate and velocity changes to gain data for the scale-up. It was shown, that the degassing pressure is a function of the flow conditions. With increasing shear rate, elongation rate and pressure drop rate the degassing pressure increases.
Micro- and Nanolayered Polymer Film Systems with Novel Properties
Recent advances in processing-structure-property relationships of micro- and nanolayer polymeric systems are presented. Coextrusion via a series of layer multiplying dies has enabled the production of films of with two or more materials that contain tens to thousands of layers with individual layer thicknesses from the micro- to the nanoscale. Nanolayered films were demonstrated with improved gas barrier through confinement of a crystalline polymer layer. In addition, unique films with layer thickness dependent optical properties including novel reflective characteristics have been developed. Redesigned layer multiplication dies we have produced gradients layer thickness films including film-foam structures resulting in unusual properties.
High Performance, Wear Resistant Thermoplastic Co-Polyester Elastomers (COPE)
New wear resistance (WR) thermoplastic co-polyester elastomers (COPE) deliver improved performance over a wide range of speed and load conditions in sliding or moving applications. These elastomers have excellent cold temperature impact strength and work well at a broad range of temperature and humidity conditions, primarily in injection molded articles. Various grades with wide range of hardness are suitable for applications requiring excellent tribological properties. These elastomers provide outstanding ductility combined with the excellent chemical and environmental resistance properties of polyesters. The unreinforced and higher flexibility COPE grades fill the property gap between standard thermoplastic polyester urethanes and vulcanized rubbers by providing excellent fatigue strength and hence an increased operational lifetime. These elastomers are easy to process, recyclable and retain their impact strength down to -30 °C.
Evaluation of Natural Fiber Reinforced Recycled Polypropylene Composites
This paper examines the tensile strength and Izod impact behavior of natural fibers and wood particles in recycled polypropylene composites for injection molding. The initial round of testing compares the performance of the straight recycled polypropylene resin versus non-compatibilized natural fiber or particle composites, and then the different composite performance was indicated through the addition of a compatibilizer. The mechanical properties of natural fiber or wood particle and recycled PP composites without a compatibilizer were firstly compared with those of only recycled PP. Then, some natural fiber or wood particle and recycled PP composites using various compatibilizers were investigated. It was found that the elongation at break and the Izod impact strength of some natural fiber or wood particle and recycled PP composites using specific compatibilizer were indicated for high flexibility and adhesive formation as compared with some natural fiber or wood particle and recycled PP composites without a compatibilizer. The difference between natural fibers and wood particle was also discussed.
Prediction of Process Window for Plastic Injection Molding Using Simulation Tools and a Support Vector Machines Classifier
Traditionally, setting of process parameters is significant for quality of molded parts and is a highly skilled job on the plant floor in plastic injection molding. The process window is especially instructive for this job. However, it is difficult to be depicted and obtained since it is an irregular region in a multi-dimensional space of process parameters. In this study, the process window is implicitly defined by a fitting of sample data from simulation results. Design of experiment, simulation and support vector machines classifier are combined to simultaneously fulfill the requirements of computational efficiency and prediction accuracy.
Mechanical Properties of Biodegradable Poly(Butylene Succinate) Blended with Poly(Ethylene Terephthalate) Recycle
This research was carried out to improve mechanical properties of PBS by melt blending with recycled PET flakes from drinking bottles. Content of PET adding was 1, 2 and 5% by weight. Properties of polymer blends were evaluated by tensile test, impact test, SEM, DSC, and TGA. It is found that blending PET into PBS yielded stronger mechanical properties compared to neat PBS. However, melt blending between them required high temperature enough to melt PET flakes, so it caused thermal scission in PBS molecules as evidenced in TGA analysis. PBS/PET blends had higher tensile modulus but reduced flexibility with higher PET content. For DSC analysis, it is found that blending PBS with PET increased crystallinity of PBS matrix due to nucleating effect of PET dispersed spheres.
Thermoforming Radiation Crosslinked Polyamide – Effects of Degree of Cross Linking and Thermoforming Processing Conditions
Semicrystalline thermoplastics generally have a smaller processing range for thermoforming compared to amorphous thermoplastics, due to their narrow temperature window for the transition from viscoelastic to viscous material behavior. Otherwise they offer superior properties for applications like ductility or chemical resistance. Previous research showed that cross linking of semicrystalline thermoplastics by high energy irradiation holds the potential to significantly improve their thermoformability. Within this article the effects of different degrees of cross linking and their interaction with processing conditions during thermoforming shall be discussed.
Solid Phosphorous Based Flame Retardants in Impact Modified Polycarbonate Blends for Superior Properties
Phosphorous based flame retardants have been widely employed as eco-friendly flame retardants for impact modified polycarbonate (PC) blends but some of the liquid phosphates cause significant deterioration in key physical properties like impact strength and heat deflection temperature. This work shows results from recent developments at SABIC in order to achieve superior physical properties while maintaining thin-wall UL94 V0 ratings by using solid phosphorous based flame retardants. Additionally, some of these blends also show significantly improved hydrolytic stability which could translate into a more sustainable solution enabled by longer service life for parts made out of such materials.
Novel Conductive Hybrid Nano-Composites for Electro-Mechanical Sensors
The present investigation describes a facile and rapid approach of production of conductive nano-composites, and assessment of the opportunity for using them as electro-mechanical sensors. The new synthesis procedure includes an in-situ inverse emulsion polymerization method of aniline in the presence of CNT and dissolved thermoplastic elastomer, followed by a precipitation-filtration step. Incorporation of CNT/PANI in the SIS elastomeric matrix improves the thermal, mechanical and electrical properties of the nano-composites. Formation of the continuous three-dimensional CNT/PANI network, is responsible for enhancement of the resulting nano-composite properties, such as the relatively high electrical conductivity levels. The described novel approach provides an opportunity for developing tunable structures of remarkably distinctive architecture. The rapid electrical resistance response to the applied strain makes the developed nano-composites useful as sensitive strain sensors.
Hybrid PANI/CNT Nanocomposites Prepared by an Inverse Emulsion Polymerization Technique
Carbon nanotubes (CNT) have drawn much attention in recent years. CNT have remarkable properties i.e. mechanical properties, electrical and thermal conductivity, thus offering opportunities for development of new nanocomposites. An homogeneous dispersion of nanoparticles in polymers using conventional processing techniques is difficult to produce since nanoparticles tend to agglomerate, thus efficient methods for agglomerate breakdown have been sought in recent years. The combination of CNT with intrinsically conductive polymers may lead to new and improved properties of the resulting materials. This work describes an in-situ inverse emulsion polymerization method of aniline in the presence of multiwalled carbon nanotubes (MWNT) in organic solvents using ultrasonication. PANI dispersion, as a reference, and the PANI/MWNT dispersions were stable for long periods of time without visible precipitation. Highresolution scanning electron microscopy (HRSEM) has shown that MWNT are coated with PANI, leading to a remarkably improved dispersability of the nanotubes, thus PANI coating reduces the tendency of MWNT to reagglomerate. The neat MWNT have a diameter of ~10nm, while the core-shell MWNT/PANI nanofibers exhibit a diameter of ~40nm. The dispersions obtained may have important potential applications in the fields of sensors, acoustic actuators, semi-conductors, solar cells and more. CNT containing materials suitable for the manufacture of thin, transparent, electrically conductive films have poor mechanical properties and are expensive. Our work on hybrid conducting nanocomposites has led to a remarkable combination of high conductivity and transparency along with low haze and good mechanical properties, aiming at competing with the existing ceramic materials, such as Indium Tin Oxide, (ITO).
Highly-Tunable Polymer/CNTs Nanostructures: A Rapid and Facile Approach for Controlled Architecture and Composition
This research presents a new fabrication method for tailoring polymer/carbon nanotubes (CNTs) nanostructures with controlled architecture and composition. The CNTs are finely dispersed in a polyacrylate latex, via ultrasonication, followed by a microfiltration process. This step allows preserving the uniform dispersion structure in the resulting solid nanocomposite. This original fabrication method is applied for supercapacitorc, biocatlytic membrane and low reflecting coatings. The combination of microfiltration and proper choice of the polymer latex allows the design of complex nanostructures with tunable properties e.g., porosity, mechanical properties. An important attribute of this methodology is the ability to tailor any desired composition of polymer-CNTs systems, i.e., nanotubes content can practically vary anywhere between 0 to 100 wt%. Thus, for the first time a given polymer/CNTs system is studied over the entire CNTs composition, resembling immiscible binary polymer blends. The polymer in these systems exhibits a structural transition from a continuous matrix (nanocomposite) to segregated domains dispersed within a porous CNTs network. An analogy of this structural transition to phase inversion phenomena in immiscible polymer blends is suggested.
High-Temperature Steam-Treatment of PBI and Its Blends with PEEK and PEKK: A Solid-State NMR Study
Blends of polyaryletherketones (PAEK), such as polyetheretherketones (PEEK) and polyetherketone-ketones (PEKK), with polybenzimidazole (PBI) are of commercial interest due to their improved high-temperature stability and wear properties. Regarding the PBI component, the origins of the properties that are generally thought to be disadvantageous in thermally or chemically aggressive environments are not well understood. The same accounts for the specifics of the interactions between the PBI and PAEK components in melt or dry blend systems. In this presentation, we focus on the molecular changes of PEEK-PBI and PEKK-PBI blends and their pure components after treating them with liquid water and steam at elevated temperatures and pressures. The pure polymer components and the PAEK-PBI (50:50 wt%) blends are steam-treated at 150 °C (302 °F) and 315 °C (599 °F), also with deuterated water (D2O). The overall goal is to understand the chemical changes on the molecular scale that might take place upon high-temperature steam-treatment and to examine the extent and reversibility of moisture uptake. Changes of the materials, as well as interactions and reactions of the water with the functional groups of the polymer components have been studied by 15N and 13C CP/MAS, 2H MAS, and 1H wideline NMR spectroscopy, in combination with using deuterated water.
Influence of Cellulose Fiber on the Foaming Behavior of a Polypropylene Copolymer
This paper investigates the effect of different cellulose fiber grades on the rheological properties and the foaming behavior of a linear polypropylene copolymer. Three cellulose fiber grades with different fiber lengths were used in this study. The average length of the fiber grades were 300 ?m, 500 ?m and 700 ?m. The preparation of the compounds were carried out on a co-rotating twin screw extruder and the foaming experiments were executed with a grooved feeded 45 mm single screw extruder. For the foaming experiments supercritical CO2 was used as blowing agent. All compounds were characterized with a cone plate rheometer to compare the influence of the fiber length and the amount on the rheological properties. The different formulations were compared, due to their effect on the maximum cell density, in terms of cell size and the foam density. It was shown that the effect on the materials viscosity increases with increasing fiber length. The foam morphology was not affected by the fiber length. However the volume expansion ratio depends on the fiber length.
Styrene-Butadiene Rubber- Surface Modified Carbon Nanotube Nanocomposites: Morphology, Rheology and Dynamic Mechanical Properties
Because of the exceptionally high modulus of multiwall carbon nanotubes (MWCNT), they can be used as reinforcing fillers in polymer and rubber nanocomposites. However, the commercial implementation of such nanocomposites has generally been met with very limited success owing to poor dispersion of the MWCNT in the polymer matrix. A strategy that overcomes many of these difficulties is described here with a view towards replacing a portion of the carbon black or silica with MWCNT for improved elastomer performance. Tire treads are very prone to experience micro-cracking at the edges, which eventually leads to overall failure. MWCNT can serve as good bridging elements to avoid the growth of micro-cracks if they are well dispersed and discreet in the rubber matrix. A concentrated, easy to process MWCNT-rubber masterbatch, with the freedom of diluting to various lower loadings, and feasibility of blending with different rubbers, would be of commercial benefit to the tire industry. Discreet oxidized MWCNTs were dispersed in an SBR matrix and the rheology, tube dispersion, dynamical mechanical, and electrical properties of these composites were examined. Morphology and mechanical properties of the cured nanocomposites were investigated and related to the effective aspect ratio of MWCNTs.
Quinacridones – A High Rolling Performance Overview and Winning Styling Options
Quinacridone chemistry provides impressive high performance organic pigments for diverse applications and industries. These heterocyclic compounds achieve color range abilities through auxochromic substitutions such as methyl and chlorine groups, as well as polymorphism. Solid solutions of mixed quinacridone molecules further the already expansive coloring options. Chemical fortitude of lightfastness, bleed and heat resistance can generally be attributed to molecular lattice interactions and surface chemistry. With bright tones and good tinting values, quinacridone pigments permit coloration with high performance characteristics. This paper provides an overview of quinacridone pigments from molecular identification to color point position as well as typical polymer suitability and performance.
Graphene-Based Multilayered Poly(Methyl Methacrylate) Nanocomposites via Forced Assembly Coextrusion
The ability to achieve enhanced mechanical properties through in-plane orientation of platelet-like nanofillers is a challenge for nanocomposite fabrication and performance. Here we use forced assembly to orient graphene nanoplatelets in PMMA/PMMA-graphene films produced through multilayer coextrusion. Electron microscopy confirms the alternating layer structure of PMMA and PMMA containing oriented graphene. Relative reinforcement of 11 % at a concentration of 0.2 wt % graphene in the total film was achieved without loss of toughness. The reinforcement is attributed to the planar orientation and improved dispersion of the graphene as the layer thickness decreases.
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