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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Analysis of Resin Flow under Flexible cover in Vacuum Assisted Resin Infusion
Techniques to simulate resin infusion using classical RTM simulation software are investigated. The difference in the filling behavior between “rigid” and “flexible” molds is evaluated and explained. A model describing the evolution of permeability with pressure is developed for flexible moulds. This model takes into account the changes in thickness of the cavity following deformations of the mold cover as well as the compressibility of the reinforcement. The model is validated by comparison of numerical simulations for a complex automobile part manufactured by resin infusion with actual test results obtained at the factory
No Postcure RRIM for Automotive Exteriors
Reinforced reaction injection molding (RRIM) has reemerged as an important method in automotive exterior applications. Presently composite applications demand higher productivity and improved part performance. Stability at higher heat to endure E-coat oven bake improvements in fillers yielding easier processing at high loading improved toughness at high modulus and higher productivity have already been realized with RRIM in Europe and NAFTA. Now the kinetics of one new material Bayflex 190 is such that reaction is essentially complete at demold. In the past RRIM molded parts were required to be baked at 120oC and above to complete chemical reactions attain complete physical properties and de-gas parts prior to painting. In current E-coat applications postcure of 190oC is typical. Elimination of postcure means significant savings in energy increased productivity decreased handling and lower capital expense. Bayflex 190 polyurea attains virtually all properties at demold. After molding parts can be washed and primed directly. Dynamic mechanical analysis shows that further heating to 200oC anneals and strengthens the composite. Several very sensitive analytical methods have been employed to characterize the degree of cure at demold. Differential scanning calorimetry (DSC) shows no exothermic chemical reaction up to 200oC. Thermal gravimetric analysis (TGA) shows no CO2 loss from unreacted isocyanates. And Fourier transform infrared spectroscopy (FTIR) scans indicate no free isocyanate in freshly molded samples. Parts painted in production exhibit no defects associated with elimination of postcure.
Designing for Durability Using an E-Glass Reinforced SRIM Urethane Composite
The durability of a SRIM Urethane composite are evaluated and the results are used to develop a design guide to aid in the use of this material. Test methods for static fatigue creep and impact testing are described in detail. The Oak Ridge National Laboratory developed these methods for durability testing. The raw test data from an earlier study are summarized and generalized in the form of design equations. The scope and limitations of these design equations are discussed. This material evaluation and data summary process provides a means for designing for durability using an E-glass reinforced SRIM Urethane composite.
The Use of UV Light for Surface Cleaning for Painting and Adhesive Bonding of Composites and Metals
Contemporary vehicles utilize a mix of materials in their construction consisting of metals plastics and composites. These materials must possess suitable surface properties to achieve desired performance when these parts are adhesively bonding or painted for field service. Surface preparation methods now in place oftentimes use solvents or caustics an increasingly unacceptable approach in an era of mounting environmental regulations. New methods of surface preparation are called for that are environmentally benign and economically feasible while meeting the stringent quality standards of the automotive industry. The use of energetic ultraviolet light is emerging as a promising technology to compete with the old methods of surface preparation. This paper reports the utility of using energetic UV light to generate appropriate surface chemical composition on plastics composites and metals for subsequent painting or adhesive bonding operations. UV treatments have the potential to replace the old methods of treating assorted materials used in the automotive industry in an environmentally responsible and cost-effective manner.
Enhanced Bonding of Polypropylene to Polypropylene and other Materials with Novel Thermoplastic Heat Activated Adhesives
It is commonly accepted that bonding polypropylene to itself or other adherends is difficult and the options available for cost-effective bonding using adhesives are very limited. The aim of the presentation will be to describe a new range of heat-activated adhesives recently developed in our research laboratories and their applications. These adhesives which are now commercially available offer numerous advantages for the rapid manufacture of composite materials in addition to promoting new or improved assembly methods in a wide range of market sectors. e.g. automobile aerospace construction textiles footwear and packaging to mention but a few. The main focus of the presentation will be to outline various ways in which the film strand or pellet forms of the new adhesives may be used to solve a variety of industrial problems. The range of materials to which polypropylene can be successfully bonded (e.g. to itself to many metals and to a range of other materials notably cellulosics) will be outlined together with their associated manufacturing methodologies such as hot compression lasers and induction heating. An indication of the mechanical bond strengths which can be achieved at various temperatures will also be outlined.
Electrochemical and Stack Evaluation of Composite Bipolar Plate Materials
Composite plate materials for use as bipolar plates in a fuel cell stack must meet certain performance criteria namely high surface and through-plane electrical conductivity very low gas permeability and chemical resistance to both coolants and reactants. In addition to these performance criteria it is necessary from a cost viewpoint that the bipolar plates are easy to manufacture. One category of materials being used for bipolar plates are carbon composites where carbon additives are mixed with a thermoset resin for net-shape compression molding of bipolar plates. A study of the corrosion resistance (via electrochemical testing) helium permeation stack performance and electrical conductivity of a variety of composite materials designed for bipolar plate applications will be presented.
Polymeric Composite Bipolar Plates for Vehicle Applications
At present membrane electrode assembly performance levels and stack operating conditions of PEM fuel cells a plate area specific resistance of less than approximately 20 mohm cm2 and a plate thickness of less than 2 mm are required to meet the vehicular volumetric power density target (> 2 kW/l). It is however difficult to meet these aggressive requirements and simultaneously obtain good mechanical properties when using polymeric plate materials. Polymers become brittle and break frequently at the high conductive filler loadings (e.g. > 50 v/o graphite) required for high conductivity. This study investigates a potential approach for obtaining high plate conductivity at low conductive filler loadings thus enabling high volumes of thin and ductile plates to be manufactured at low scrap rates.
The All Composite One Piece Bumper
Composites Use In Heavy Truck
Real Time Cost Impact Assessment of Composite & Metallic Design Alternatives
This paper discusses how a process-based parametric cost model SEER-DFM is used to facilitate the real time cost impact assessment of composite and metallic design alternatives. The main purpose is to introduce the underlying cost model methodology and demonstrate its flexibility for developing trade studies. Readers are introduced to the model its premise and how engineers use it to obtain substantial cost savings through ‘real world’ examples.
Conformal Cooling with Solid Freeform Fabrication Technology: Issues & Opportunities
Solid freeform rapid tooling technologies of various sorts have promised new conformal cooling advantages for plastic tooling. In principle these technologies offer geometric design freedoms unavailable by machined or EDMed approaches. In practice all solid freeform approaches are not equal. This paper will discuss opportunities and limitations on design freedoms and important issues associated with material properties; and will show that raster-scanned 3D Printing technology has matured to a point of delivering on the promise.
Composite Design Procedures for Racing Cars
New Application Technologies in Phenolic Moldable Composites
Presentation at ACCE 2003.
Carbon Fiber Composite Applications for Auto Industries
Carbon fiber composite drive shaft having crush worthiness which had been developed for rear drive passenger cars will be described. Crash load generated during head collision can be absorbed by newly developed joining technology with no adhesive between carbon fiber composite tube and steel adapter. This technology can add safety value to passenger cars in addition to conventional advantages of composite drive shaft such as weight and noise reductions. Its materials design concept performance data of the composite drive shaft system will be discussed in the paper.
Renewable Source Materials Phase II
In phase I soy-based polyesters were introduced in the form of sheet molding compound (SMC) to be used in farm equipment such as combines. In phase II soy-based polyester will be evaluated in the spray- up infusion and resin transfer molding (RTM) processes for similar types of application. Each system was evaluated at room temperature and 120 ° F for surface quality cure and molding ability. This paper will discuss shrink control for room temperature cured parts and surface quality as compared to automotive standards. Physical property data will also be compared to standard polyesters and SMC used in these fields.
Tough Sheet Molding Compound
One of the biggest challenges facing molders of automotive exterior body panels is the reduction of paint pops. Minimizing or eliminating paint pops would greatly reduce manufacturing costs by minimizing rework painting and scrap material. A new SMC formulation has been developed that is more resilient and durable than standard Class A SMC. The material is more resistant to micro cracking the primary source of paint pops while maintaining the physical properties and surface quality required for Class A exterior body panels.
Decorative Laminates For Thermoforming and Insert Molding Processes
Decorative films laminated to plastic substrates have been used for many years but the recent wave of technological advances and increased competition offer more variety in design colors materials and performance properties than previously available. This offers part designers and plastic processors the option to use decorative laminate technology for more applications while reducing costs eliminating environmental concerns conversion from non-plastic materials and improving product performance.
Tailored LFT-D Technology
Improvements in Impact and Abrasion Performance of Glass Fiber Thermoplastics by the Localized Introduction of Self Reinforced Polypropylene
The past few years have witnessed a rapid growth in the use of glass reinforced thermoplastics for automotive applications. New developments in LFT's and GMT's are beginning to meet the industry's demands for complex modular components – such as front ends instrument panel carriers and underbody assemblies – with low-cost lightweight materials which have acceptable mechanical performance. However in terms of damage tolerance particularly resistance to heavy impacts and abrasion LFT's and GMT's are no match for the metals they are designed to replace. This paper will describe the use of a highly impact resistant self-reinforced polypropylene composite to provide localized reinforcement in GMT and LFT components without increasing weight or compromising recyclability.
Fabrication Processing & Mechanical Properties of Flat Braided Thermosetting Composites Using Natural & Coated Jute Yarn
This paper submits investigation on the tensile and bending properties of the flat braided thermosetting composites made using jute yarns. Combining flat braided jute yarns (untreated and coated) and vinylester resin composite specimens were manufactured by hand lamination method. Tensile and 3 point bending tests were conducted. Test samples were polished and pre- and post-failure examinations were carried out using optical and scanning electron microscopy in order to analyze the test results and their relationships to the state of resin impregnation into the fibre bundles fibre/matrix interfacial properties and the fracture and failure mechanisms. While tensile properties were slightly degraded due to coating treatments bending properties of the composite showed improvement when coated yarns were used. These variations in the mechanical properties were broadly related to the state of resin impregnation into the fibre bundles and/or fibre/matrix interfacial interactions.
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