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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This study investigates the factors affecting the welding of pine, maple, and bamboo pulp-board. This research used a Branson Mini II vibration welder traditionally used for welding plastics. The effects of weld pressure, amplitude, and weld time were varied to determine their effects on lap-shear weld strength. Strength testing was performed with a universal testing machine. The morphology of the weld zone was also analyzed to gain insight into the welding mechanics. The highest strength of pine samples was 8.4 MPa, while maple was approximately 35% stronger and had a smaller standard error. It was observed that bamboo pulp board weld strength was primarily dependent on weld pressure. Also, pulp-board seemed to weld in a similar fashion to wood.
In this study, PET was combined with a latent metal oxide reagent, CaO, which allowed the PET to hydrolyze when submerged in water, breaking down the polymer chain and forming calcium terephthalate as a nontoxic byproduct. PET/CaO composites were mixed at 10, 20, and 30 wt% CaO, and 0.001” thick films were prepared by compression molding. These films were degraded in water at 90°C for varying amounts of time. Puncture testing, optical microscopy, FTIR, and TGA were performed to probe the degradation of the material and verify that it was producing the products that were expected from the reaction. The PET/CaO composites were shown to be degradable in water, with a significant loss in mechanical properties after only an hour. The rate of degradation was strongly dependent on the concentration of CaO, with significantly faster degradation at higher concentrations.
This work demonstrates the efficacy of amorphous polyhydroxyalkanoate (a-PHA) copolymers in enhancing the impact strength of PLA without compromising the compostability and bio-based carbon content of the final product. The influence of PHA polymer composition on the performance of PLA will be highlighted for applications including thermoforming, film and injection molding. Finally, the morphology of the blend will be used to explain the impact modification mechanism. Blends of 100% bio-based and fully biodegradable a-PHA and PLA exhibit good toughness and clarity in injection molding, extruded sheet and blown film. It will be shown that the level of toughness increase and modulus reduction can be tuned by blend composition.
Aqueous polyurethane dispersions based on castor oil and lignin sulphonate (LS) were successfully synthesized in homogenous solution with no organic volatile compounds and excellent dispersion stability. Transparent thin films of PU-LS with different LS contents were obtained via solution (dispersion) cast technique. The glass transition temperatures (Tgs) of the PU-LS films were evaluated from the dynamic mechanical analysis (DMA) at 1 Hz and 2 oC/min heating rate. The Tg was found to be strongly influenced by the incorporation of the small LS content. The Tg (temperature of tand peak maximum) for PU-LS film with LS content lower than or equal 3 wt.% increases considerable with increasing the concentration of LS. For higher concentrations, no significant additional increase in the Tg was observed. The crosslink density was also calculated from the elastic modulus at a temperature of 40 oC higher than the Tg based on the rubber elasticity theory. The crosslink density increases with increasing the LS content of the thin films. The thermal-induced shape-memory effect was investigated using DMA according to cyclic thermomechanical tensile tests. The PU-LS thin film was found to have an excellent shape-memory effect and the recovery was strongly dependent on the LS content. Fast recovery (17 sec) to the permeant shape was observed once the temporary shape sample was immersed in water bath at the programming temperature.
An alternative to bisphenol A was used to synthesize polysulfones (PSs) that are chemically recyclable. Vanillin was reacted with 4-aminophenol to generate a diphenol with an imine. The synthesis of PSs is done by means of polycondensation of dibasic phenols with sulfur-containing aryl halides by the mechanism of nucleophilic substitution. The lignin based diphenol replaces traditionally used bisphenols (a xenoestrogen) and is the site for recycling the polymer. The polymerization is studied under various conditions (temperature, time, monomer ratio) for best properties and product purity. The polymer structure was confirmed via NMR and its thermal properties studied using DSC and TGA (Tg~122°C, Td5~270°C, Td10~400°C, Tprocess~180). The stability of the imine bond was studied under the reaction conditions for reactant stability.
Applications for automotive battery systems require hybrid joints of copper and polymer with high demands towards helium seal tightness and long-term durability. This work examines hybrid bonds, using indeterministic laser-nanostructures as pretreatment and variotherm injection molding as a joining method. Laser nanostructures are produced with two different laser setups; one having a mean power output of 20 W (state of the art) and one system with 200 W, promising faster processing rates by one order of magnitude. The spot distance and the number of laser pretreatment repetitions are varied systematically for both laser systems. All treatment variations are joined by variotherm injection molding using inductive heating of the metal specimen. A polyamide 12 compound with 10% glass fiber content is used. Bonds are tested for shear strength and helium seal tightness and the degradation of these properties due to ageing. For root cause analysis, the boundary layer is analyzed using ion beam cross-sectioning and SEM-imaging.
Abstract Submission Effective Antimicrobial Protection for Automotive Composite Applications by F. Deans & Dr. H. Khan A growing concern that OEM’s, suppliers, and dealers have is how to protect their customers from exposure and transmission of harmful pathogens. The market has been flooded with a number of products for direct human use. However, there remains unanswered data and details on how to effectively utilize antimicrobial agents for automotive components that could come into contact by human occupants. Specific information on types of antimicrobial performance, manufacturing techniques on protecting plastic and composite applications, and prolonging the antimicrobial effectiveness will be discussed.
Environmental consciousness is driving modern research and development in the automotive sector to target the advancement of feasible green materials in automotive applications. Basalt fiber has shown to be a robust competitor against glass and carbon fiber and is more eco-friendly manufacturing processes. Reinforcing polypropylene with basalt fiber and hemp hurd using maleic anhydride-grafted polypropylene (MAPP) as a coupling agent, has shown to contain similar mechanical properties to its competitors. A mixture model was implemented to optimize the mechanical properties of a variation of fiber ratios and MAPP to compare against a controlled GF mixture. Scanning Electron Microscope (SEM) analysis of fracture surfaces show the variation in fiber–matrix adhesion based on addition of MAPP. This study concludes that the addition of MAPP improves the mechanical behaviors of hybrid composites made from basalt fiber and hemp hurd reinforced polypropylene.
Automotive manufacturers have been increasing use of natural fiber composites to reduce vehicle weight and respond to consumer demand for environmentally friendly products. However, the low thermal stability of natural fibers can limit their use to low-processing-temperature polymers and low-temperature automotive environments. Pyrolysis of biomass results in the formation of a porous substance called biocarbon, which can improve composite thermal performance, eliminate odor, and reduce hydrophilicity. The objective of this study was to investigate the effects of biocarbon on the performance of biocarbon-glass fiber hybrid composites for use in under-the-hood automotive applications. This study evaluated the macroscopic (mechanical performance, density) and microscopic (SEM) characteristics of biocarbon-hybrid composites with varying loading level and biocarbon type. Biocarbon-hybrid composites were approximately 10-13% lighter than currently used fan-and-shroud materials and the addition of biocarbon content improved composite flexural strength & modulus.
The recyclability of natural fiber and glass fiber reinforced polypropylene composites and glass fiber reinforced nylon composites have been studied through injection molding and mechanical grinding. Mechanical properties of virgin and recycled composites were assessed through flexural, tensile, and impact tests. No significant degradation in the mechanical properties of natural fiber composites was observed after subjecting the composites through several rounds of recycling and water absorption at ambient temperature in tap water. However, severe degradation in the mechanical properties was observed for glass fiber composites. For instance, after five cycles of recycling, only 59% of flexural strength and 64% of flexural modulus was retained for glass fiber reinforced nylon composite. This is mainly due to severe attrition in glass fibers caused by recycling as evidenced by studies on fiber length distribution. Water absorption tests conducted at room temperature and subsequent environmental conditionings such as freeze-thaw cycling and extended freeze cycling only affected nylon composites. At saturation point, water absorption for nylon composites was 7.7% by wt. after 45 days of immersion, which significantly affected the mechanical properties. The tensile strength of the nylon composites reduced from 88.4 MPa to 36.2 MPa, and modulus reduced from 5.6 GPa to 1.8 GPa after saturation.
This paper will treat to expose the complexity of stabilization of plastics in automotive applications. First, we will review some basics on stabilization, the use of phosphites and phenolic antioxidants. We will cover the different aspects of polymer stabilization: during processing and along the service life of the parts. This will involve discussion around light stabilization too. Along this paper, we will see some examples of outstanding chemistries than can lead to combine several benefits to achieve the performances required by OEMs.
Fuel economy and emission regulations are challenging automotive manufacturers to meet global targets, which are becoming more stringent over time, in particular, for internal combustion engine powered vehicles. Internal combustion engines will likely remain dominant for a long time and will require system innovations or in many cases electrification solutions to meet the regulations. This document describes the thermoplastic material solutions to meet the application functional requirements of engine solutions, such as turbocharging, exhaust gas recirculation and gasoline direct injection that are the current trend for system innovations of light-duty vehicles.
In this work, digital image correlation was performed during compression testing of twodifferent flexible polyurethane foams to obtain full-field strain maps and understand the non-uniformdeformation the foams exhibit. In addition, X-ray micro-tomographywas performed on the foam samples at different locations through the thickness to obtain micro-tomographs of the foams’ microstructures. Measurements and statistical analysis from these micro-tomographs made it possible to quantify the cell size distribution and their variation through the thickness, as well as identify differences in the microstructures of different foams.It was found that observations from compression tests with digital image correlation are in good agreement with observations from X-ray micro-tomography analysis.
Ever since the first polymer applications were incorporated into the automobile in the 1960’s, OEM requirements for polyolefin based automotive compounds have pushed the performance envelope with respect to, for example, improved mechanical properties such as flex modulus, tensile strength, and heat distortion temperature; aesthetic properties such as surface quality; processing characteristics such as viscosity; and as always, cost. However, density was not a critical concern since the part being replaced was most probably made of metal. To attain required physical, esthetic and viscosity properties such as those listed above, compound formulations have become very complex. The main additives to the base polymer in early automotive applications such as a battery tray, were typically glass fiber and/or mineral filler for reinforcement. However, as manufacturers have continued to push vehicle weight reduction, they are re-evaluating specifications for current polymer-based applications/parts, i.e. bumpers, trim, etc., for future model years. In most instances, all the specified mechanical and flow properties remain the same, but density is reduced between 5 and 10%. Generally, this requires an extensive material reformulation to meet the new specifications. As part of most light-weighting reformulations, high bulk density filler content is decreased and replaced with multiple grades of polypropylene having a wide range of viscosities. These resins need to be melted and uniformly blended to provide, for example, strength from a high MW, high crystallinity component and good flow characteristics from a low MW grade. Additionally, any IM (impact modifier) needs to be dispersed and uniformly distributed. For reinforcement to be effective, fibers need to be unbundled as well as maintain a critical length during the compounding process. Minerals, depending on their structure, need to be distributed and/or distributed and dispersed. The co-rotating twin-screw compounder has long been the equipment of choice for such compounding functions. However, compounders still face processing challenges such as how to optimize the extruder set up to uniformly compound 1) diverse viscosity matrix polymers, 2) incorporate and disperse impact modifier, 3) unbundle and distribute fibers, and/or 4) feed, distribute and disperse a poor flowing, “sticky” mineral filler or possibly an easy to fluidize low bulk density talc while simultaneously maintaining an economically viable production rate. Additionally, the process can be challenged to maximize fiber length in high viscosity mineral filled formulations. This paper will review requirements for compounding automotive polyolefin compounds with an emphasis on recent innovations in Co-rotating Twin-screw technology that have enhanced product quality and productivity for these complex lightweighting material formulations.
The development of a high stiffness Polypropylene (PP) foam for use within the rotational moulding industry has been investigated by Matrix Polymers. The scope is to offer a stiffer and more advanced alternative to the current Polyethylene (PE) foams which are on the market. Matrix Polymers want to push the boundaries of current products and combine new technologies to produce a new material. Differing compositions of CBA (chemical blowing agents), various dry blends and compounds have been trialed alongside experiments into the CBA reaction time and expansion ratios. The availability of K-kord temperature logging equipment has been utilized alongside JUST RITE temperature labels, static oven machines and a rotational Ferry machine to develop the new material. All of the above has furthered understanding into the astonishing potential of this new material. Offering this product to the rotational moulding industry would be greatly beneficial to rotational moulders from around the world in a variety of applications, we understand the limits of rotational moulding are the lack of suitable polymers. This is something that Matrix continues to challenge.
In the plastic industry, the modification of polymers with glass or carbon fibers is common to improve the product quality and properties. Particularly, the twin screw extruder is frequently-used for continuous compounding, preparation and processing of polymers. The steadily growing demand for fiber-reinforced thermoplastics and the high cost of the carbon fibers are the motivation for recycling. Furthermore, new laws (e.g. EU Waste Framework Directive and End-of-Life Vehicle Regulation) demand the recycling of the remains and the waste of the carbon fiber production.
Extrusion blow moulding enables the cost-effective production of plastic hollow bodies with complex geometries and different volumes. The majority of the components are used as packaging articles for the consumer goods- and food industries or as technical components, e.g. in the automotive and chemical industries. Extrusion blow moulded products are often failing at the weld line. The quality of joint depends mainly on the welding temperature. In order to improve this critical area, the IKV is investigating the use of variothermal temperature control of the blow mould. This brings the advantage of being able to locally increase the temperature of the blow mould. By using this temperature control concept, the results show a significant improvement in the quality of the weld line.
This paper should help engineers and designers to make best possible use of PA66-based engineering materials in the context of components that are subject to vibration or the damping of vibrations in automotive. It will provide results from material testing, discuss these results and provide guidance, how these measurement results translate into components. Proven concept to reduce the propagation of vibrations is the use of elastomer elements as damper for example at bearing points within the suspension system or in engine mounts. With thermoplastics being introduced to also the rigid parts of these systems, there is an additional potential to eliminate vibrations thanks to the viscoelastic behavior of this class of materials. PA66-based materials are widely used for components in the engine compartment and the suspension system because of their capability to provide sufficient mechanical properties, thermal stability and chemical resistance. The goal of this paper is, to highlight the influence of glass fiber reinforcement, impact modification and humidity content on the damping behavior of PA66-based materials and to explain the variability of the internal damping as a function of these variables.
The goal of this research is to further the understanding of the relationship between flow properties, orientation, and related mechanical properties of injection molded parts. The properties and behavior of the flow of a fiber reinforced polymer composite during molding is directly related to the stiffness and the strength of the completed part. Flow affects the orientation of the fibers within the polymer matrix and at locations within the mold cavity. Mechanical properties of fiber reinforced polymer parts, such as stiffness and strength, are controlled by the average length of the fibers and how the fibers are oriented. The ability to predict, and ultimately control, flow properties allows for the ability to efficiently design safe parts for industrial uses, such as vehicle parts in the automotive industry. A lab developed simulation packaged has been designed to predict the orientation and modulus of long glass fiber reinforced polypropylene composites. With the improved simulation package, the flexible fiber model was proven to be more accurate for predicting fiber orientation than the traditional rigid fiber model. The goal of this work is to test the universality of the existing model using long carbon fiber reinforced nylon 6,6 composites by injection molding parts and then performing experiments to check their tensile strength and the modulus. The methodology for collecting the data and the ability of the simulation to converge has been proven for the new material. The universality of the simulation package will be determined by comparing the accuracy of the results for the two materials.
This paper presents the processing methods for producing functionally graded rapid rotational foam molded foam composites with supercritical CO2. The cell density of the foamed core is deliberately varied across the length of the part by gradually increasing the talc content from 1 wt% to 3 wt% or by increasing the chemical blowing agent content from 0.5 wt% to 2 wt%. The foamed core of the composite is produced with foaming grade LDPE. The cellular morphology is characterized by its foam density, average cell size, and cell density across the length of the part. A scanning electron microscope (SEM) was used in the characterization process at 37X magnification along with a digital microscope at 30X magnification. The analytical characterization of the foam revealed, LDPE foamed core processing is more suitable when the chemical blowing agent (CBA) is combined with the physical blowing agent (PBA) rather than just utilizing talc with PBA. The cell density within the water-cooled LDPE foam was 1.4e6 cells/cm3 with an average cell size of 137 um. These results demonstrate the capabilities of a new experiment setup designed to combine PBA foam extrusion and RRFM technology.
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