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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Engineering Software for Designing Cost Effective Mixed Material Vehicles
This presentation discusses issues that must be addressed by engineering software tools currently used for metal structures and based primarily on geometry so that engineers can efficiently make the tradeoffs required to design mixed-material vehicles. Engineering software must help identify optimal combinations of materials assembly methods and joining technologies by allowing engineers to efficiently conduct tradeoffs. These tradeoffs include assembly complexity vs. part complexity the appropriate mix of material (metals plastics composites) the impact of alternative joining methods and assessment of part manufacturing and assembly alternatives while concurrently conducting an integrated design cost and performance assessment as design features are changed.
Continuing Evolution of Low Density SMC for the Automotive Market
This presentation will showcase some examples of the current market for low-density sheet-molding compound (SMC) and will provide a brief history of weight reduction initiatives and benefits in the automotive industry. One specific development program will be described in detail. This program focused on improving stiffness-to-weight ratio maximizing the benefit of microsphere technologies and creating a paint-ready surface suitable for high-appearance applications. The result was a new low-density SMC with an industry-leading density of 1.18 sp.gr. — 9% lower than the previous industry best. The discussion concludes with a peek at future opportunities for thermoset composites in this specific marketplace.
High-Volume Automotive Structural Composites: Novel Thoughts on Key Enabling Materials and Manufacturing Technologies
Fiberglass-reinforced epoxy (FG/epoxy) and carbon fiber-reinforced epoxy (CF/epoxy) composite components are known to be produced in high volumes using the compression-molding process. This same molding technology can reasonably be expected to produce high volumes of CF/epoxy automotive body structure and chassis components. The author discusses unique epoxy chemistry forming and molding processes possible due to the thermoplastic stage-of-cure referred to as the epoxy “B-stage.” B-staged epoxies are discussed and then compared to what is commonly referred to as a B-staged sheet molding compound (SMC). A progression-molding assembly line concept similar in configuration to existing automotive sheetmetal forming lines is discussed. This conceptual molding operation would be capable of producing complex CF/epoxy structural composite components at a rate of at least 120 / hour.
Decreasing VOC Emissions at the Source with New Additive Technologies for Olefin Composites
New pressures and regulations in the transportation and commercial and residential construction industries intended to improve “interior” air quality are spurring new research in additive technologies to reduce emission of volatile organic compounds (VOCs) odors and fogging for polymeric materials. Much work has already been done to help reduce VOCs odors and fogging by addressing coupling-agent purity. Unfortunately there are many pathways for the release of VOC emissions and in cases where they cannot be eliminated at the source in components of the masterbatch a third strategy is needed. One such approach described in this presentation has studied the use of adsorbents and stripping agents during extrusion compounding of the masterbatch to capture and flashoff (in the case of stripping agents) or permanently bind up (in the case of adsorbents) VOCs and fogging or odor causing emissions.
High-Pressure Resin Injection – Key Technology for Large-Scale Production
The presentation differentiates the high-pressure processes from the standard resin injection molding (RTM) processes and discusses the latest R&D results regarding the development of high-pressure RTM of high-performance fiber compounds. The focal point is set on the innovative production processes suitable for high volume as well as on the industrialization of the so-called RTM process within the high-pressure compression RTM (CRTM) process --from preforming to the final component. The compression process is of special focus. Various process parameters and their influence on part quality are highlighted and a serial process run is demonstrated.
Design and Part Performance Testing for Thermoplastic Automotive Oil Pans—NA Market
Thermoplastic oil pans are an up and coming metal-to-plastic application. With the need for light-weighting vehicles for improved fuel economy and reduced emissions thermoplastic oil pans and oil pan modules that incorporate the windage tray and oil pickup tube are under investigation at a majority of the global OEMs. At present there are 7 serial product thermoplastic oil pans most of which have just launched in the past 18 months. This presentation will provide a brief overview of OEM concerns by global region and outline the component design challenges. The focus will highlight the CAE analysis methodology used on current productions plastic pans and provide a comparison of plastic pan performance relative to aluminum or stamped steel.
Improving DLFT Molding Productivity via Lessons Learned in Non-Automotive Applications
Applying the direct-long-fiber-thermoplastics (DLFT) process to recent composite product launches outside of automotive has given a fresh perspective on how to create more effective products and efficient launches for future DLFT applications. Recent expansions of DLFT into markets such as agricultural construction personal watercraft recreational vehicles and trailers brought unique challenges that fit the flexibility of the DLFT process. Combining common materials such as glass and polypropylene with more unique materials such as wood block and recycled polymers led to a unique over- molding solution for one high-volume molding application with aggressive material cost targets. Other lower volume applications benefited from new predictive-modeling techniques of long-fiber compression molding to ensure the proper tool design of a compression molded part that weighed 40 kg and that had a length of 2.7 m could achieve a 99.9% accuracy in its length from the first shots of the tool.
Precision Waterjet Cutting in the Composites Industry Utilizing Robots for High Quality Accurate Machining
This paper discusses the coupling of 5-axis Gantry robots and 6-axis articulated-arm robots to abrasive waterjets for a range of cutting applications primarily in the composites market. The use of ultrahigh pressure waterjets and their technical advantages over conventional mechanical cutting tools are covered as well as the succesful adaptation of advanced software packages typically used in the aerospace industry. A few case studies are also presented that address composite trimming for wing skins used in aircraft and wind turbines small airframe composite parts glass trimming for high efficiency solar panels and three-dimensional machining of relatively small parts used in jet engines.
Melt-Mastication for Polyolefin Nanocomposite Dispersions
Polyolefin-exfoliated graphene nanoplatelet (xGnPTM) nanocomposites were prepared by a new process called melt mastication (MM) in which the polymer nanocomposite undergoes a mastication process that allows for enhanced breakup of larger clusters of xGnP. This presentation will present comparative results from different polyolefin- xGnP fabrication strategies including conventional melt mixing in-situ polymerization methods and MM. Improved dispersion quality with MM was confirmed using differential scanning calorimetry (DSC) and visualization of sample films by optical microscopy (OM). The nanocomposites prepared by MM showed the smallest agglomerate sizes and best xGnP dispersion followed by conventional melt mixing and finally in-situ polymerization.
Nanographene Reinforced Carbon-Carbon Composites
Carbon-carbon composites (CCC) have applications in under-the-hood and friction applications in automobiles where high heat is generated. In this study CCC was produced by using nanographene platelets (NGP) as nanofillers. Different weight concentration (0.5 wt% 1.5 wt% 3 wt% 5 wt%) NGPs were introduced by spraying the NGPs during the prepreg formation. The nanographene reinforced CCC was characterized for effect of NGP concentration on microstructure porosity inter laminar shear strength (ILSS) and flexural strength. It was found that flexure properties and ILSS increased whereas porosity decreased with addition of NGP.
Energy Absorption Characteristics of Automotive-Type Beam Structures in High-Speed Crush Testing
As part of a larger study on automotive lightweight materials / low - carbon vehicles the University of Warwick's WMG evaluated the energy - absorption characteristics of a n automotive - type U - beam structure in 3 - point bending and high - speed crush testi ng . Variants evaluated include thermoplastic composite ( laminates produced from unidirectional (UD) tapes of 60% fiber fraction by weight E - glass - reinforced polyamide 6 (PA 6 - GF60 ) ) structural steel (DP600) and structural aluminum (AA5754)) . The composit e materials were hot stamp - molded at 100 - 150 bar in a 6 0 - sec cycle in a high - speed compression press . Owing to the higher fiber fraction and orientation of the reinforcements there was very little flow forming of the materials during the molding cycle. The thermoplastic composite laminates performed well in the crush tests with superior specific properties (notably improved strength to weight and specific energy absorption ) vs. the metallic options . Additionally failure mode for the composites was con sidered beneficial vs. that of the metals as material was removed from the crush zone once it was no longer able to absorb additional energy (rather than being folded back in the metallic beams). Although for a highly loaded structural application alternat ive polymer matrices (other than PA 6) would likely be used the beam geometry was an ideal way to evaluate high - speed crush characteristics and energy absorption of pure composite and pure metallic component s side - by - side . Further the method used to pro duce the composite beams (UD tape layup plus high - speed hot stamp - forming ) offers interesting opportunities for producing highly complex void - free composite components with high levels of design flexibility since fiber orientation can be varied greatly o n each ply. G iven the rapid mold
Carbon Nanotubes: Applications and Benefits in the Automotive Industry
Thanks to their multi-functionality carbon nanotubes (CNTs)/ polymer composites have allowed the development of many innovative parts in the automotive industry that offer improved properties at competitive costs vs. metals and filled polymers. Since CNTs do not negatively influence warpage or shrinkage neither molds nor dies need to be changed to obtain required part dimensions. The benefits of electrical and thermal conductivity chemical resistance improvements in fracture toughness and compression strength and even better paintability are leading to new innovations that improve performance save weight and replace metals without need for modifying existing equipment. This presentation will discuss examples of how nanotechnology is starting to exhibit its true potential and prove that it can improve or even impart new properties to polymers which will allow researchers and engineers to develop breakthrough materials and unprecedented new technologies.
Graphene Based Impact Modified Polypropylene Nanocomposites for Automotive Applications
Graphene-based nanocomposites demonstrate superior electrical mechanical physical and thermal properties. Because of this they have moved swiftly from the research laboratory into the marketplace in applications in aerospace automotive coatings electronics energy storage and paints. Based on the huge interest enhanced properties as well as ease of production and handling the European Union is funding a 10 year $1.73 billion coordination action on graphene; South Korea is spending $350 million on commercialization initiatives; and the United Kingdom is investing $76 million in a commercialization hu because many current and potential applications for carbon nanotubes may be replaced by graphene at much lower cost. The main objective of this study was to characterize the influence of exfoliated grapheme nanoplatelets (xGnP) particle diameter filler loading and the addition of coupling agents on the mechanical rheological and thermal properties of xGnP-filled impact-modified polypropylene (IMPP) composites.
Using Nano-Carbon Templates to Control Polymer Matrix Micro-Structure Formation and Properties in the Composite
For nano-materials — in particular nano-carbons — one of the most attractive uses has been to fabricate polymer- based composites that are lightweight but exhibit high strength and high modulus. While impressive properties for such composites have been found to date one major drawback for commercial usage has been the high cost of nano-carbons. Some potential solutions to this issue have included improving the production methods to increase batch sizes/quality to drive down materials cost as well as looking at alternative nano-carbons such as graphitic nano-platelets which can be derived from cheaper carbon sources (i.e. graphite) as fillers. An alternative route to achieve nano-carbon polymer-based composites that are low cost lightweight high modulus and high strength is to use the nano-fillers as templates to modify the thermoplastic micro-structures. It is well known that polymers can exhibit high modulus (>100 GPa) and high strength (>10 GPa) if the structure can be controlled. The work outlined in this presentation shows that by using low volume percents of nano-carbons (i.e. less the 1 vol%) in the polymer the micro-structure of the matrix can be modified around the nano-carbon to influence its intrinsic properties. It has been demonstrated that the modified-polymer properties are significantly higher than the bulk-polymer component. This method provides insight into processing routes that can lead to structural control in the composite. This technology may enable the production of high-performance polymer-based composites which utilize low volumes of nano-carbons that are low-cost and thereby attractive at the commercial scale.
Effect of Fabrication and Electrical Testing on the Measured Performance of Thermoplastic CNT Composites
To fully realize the performance advantages of carbon nanotubes (CNTs) in thermoplastic composites the development process must extend beyond the formulation and production of materials. Electrical performance is strongly influenced by the fabrication processes used to form these materials into application-specific parts. Furthermore the measured properties are highly sensitive to the electrical testing configuration even when common standards- based test methods are used. This study demonstrates the impact of forming and testing effects through a simple injection molding study for polycarbonate/CNT (PC/ CNT) composites. Common electrical testing techniques were applied in standard and modified configurations and compared to characterize sources of variability. This testing suite was also used to track performance changes in injection molded parts as a result of an annealing process. This study addresses the resulting implications for evaluating the electrical performance of CNT composites in real-world applications and demonstrates the opportunity to adapt standardized methods as application-driven tests throughout the development process.
New Powder In-Mould Coating for SMC in Automotive Applications
This paper describes the powder in mould coating process (PIMC) in combination with sheet moulding compound (SMC). A powder coating is applied to a preheated mould to pre-gel. SMC is placed into the mould and pressed as one with the PIMC to cure together inside the mould. When the SMC is removed from the mould it comes out coated with a highly durable super smooth powder coating layer which has a strong adhesion to the SMC. The coating has good barrier properties hardness flexibility and abrasion resistance. With the unique controlled chemistry based on durable unsaturated polyester and vinylether urethane the coating properties and curing behavior can be fine tuned to automotive requirements. Rheological curing studies were conducted to investigate the curing behavior.
Colored Inorganic Pigmented Long Fiber Thermoplastics
Long fiber thermoplastic (LFT) composites materials are one of the fastest growing materials in the polymer composites industry. Most of the thermoplastics used in automotive transportation and recreational industry are natural or black in color; and exterior painting adds to the cost of the manufacturing. Engineered plastics have higher processing temperatures that restrict the use of standard organic pigments and dyes in the processing of thermoplastics. Organic materials are not stable at higher temperatures typically above 250 degrees Celsius and degrade during processing. Alternatively inorganic particle-based pigments are acceptable for these applications because they are thermally stable to at least 800 degrees Celsius and are compatible with the polymer systems. These high performance inorganic pigments are engineered to be weather able chemical resistant and acid resistant; however in reinforced fiber composites the pigment cause fiber attrition and thereby reduction in strength. The focus of this work is on colored inorganic pigmented long fiber thermoplastic composites. The ability to integrate the color in the manufacturing steps eliminates the need for secondary painting. Pigment variables such as particle size distribution chemistry and coatings and their influence on the strength of the final part have been investigated. The paper presents the processing and performance envelopes of inorganic pigments colored LFTs in comparison to unpigmented standard LFTs.
Thermoplastic Composites in One Step: In Situ Polymerization of Caprolactam into Fiber Glass Reinforced APA6
In situanionically polymerized fiberglass reinforced composites from lactams can provide the advantages of both thermosets and thermoplastics: long fiber retention one step process short cycle times thermoformality and re-cyclability. Due to the low viscosity of caprolactam very-high glass contents can be realized which in essence makes these composites unique new engineering materials. The very strong and lightweight composites can potentially replace many existing materials in a wide field of applications.
Finite Element Modeling of Bond-Line Read-Through in Composite Automotive Body Panels Subject to Elevated Temperature Cure
Several studies have been conducted to investigate the ability of analytical tools to predict the surface distortion observed after adhesively bonding sheet molding compound (SMC) composite assemblies at elevated temperatures. This surface distortion has been termed bond-line read-through (BLRT). Initial studies using a finite element analysis (FEA) based approach showed good agreement with experimental observations and highlighted the importance of accounting for viscoelastic adhesive material properties. The current paper reviews the FEA-based approach and a parametric joint parameter study to provide background on key adhesive joint parameters. Next the results of a lab scale coupon study are presented in which measured curvature results are compared to FEA predictions. In this study several adhesive bead configurations are reviewed including a joint geometry with a machined groove. The results of this study indicate good qualitative and quantitative comparison between measured surface curvatures to FEA predictions. Lastly two analytical panel studies are presented to examine how complex three-dimensional panel geometry and local panel character line geometry can influence BLRT severity. The results of this study indicate that BLRT is a local phenomenon so that the overall panel geometry does not influence the local BLRT severity; however changes in local panel geometry can influence the BLRT severity.
THERMOPLASTIC COMPOSITES IN STRUCTURAL LIGHTWEIGHT APPLICATIONS–POTENTIAL OF UNIDIRECTIONAL FIBERREINFORCEMENT AND SANDWICH STRUCTURES
This work presents the investigations of process developments with injection molded components in combination with damaged and planar fiber structures. Fundamental experiments with tensile loaded structures in the first and flexural loaded structures in the second case are presented. The results lead to a better understanding of the influence of local continuous-fiber reinforcements in thermoplastic composites and their applicability in structural applications.
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