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

Bond-Line Read-Through Investigation for Composite Closure Panels: Initial DOE Results

Kedzie Fernholz, September 2008

Bond-line read-through (BLRT) is a distortion in a Class “A” surface that has no impact on the structural performance of automotive body panels yet it diminishes a customer’s perception of the quality of a vehicle. The root causes of this distortion are poorly understood. When a panel is discovered to exhibit BLRT in production the most straightforward solution is to increase the thickness of the outer panel–essentially adding weight for appearance. The Automotive Composites Consortium Joining Working Group (ACCJWG) has a multi-year project targeted at developing a better understanding of the causes of this distortion so that OEMs can use minimum thickness body panels and still meet customer expectations for surface appearance quality. In the first phase of this project the ACCJWG developed a tool for quantifying the visual severity of this distortion. The ACCJWG then partnered with Meridian Automotive Systems to complete a series of experiments to understand the material and process variables that influence BLRT and to determine how to minimize the severity of this distortion without increasing the thickness of the outer panel. The format and results of the first two experiments of this series will be discussed. The first experiment was a screening experiment to determine whether any of the eight factors evaluated impacted the severity of BLRT. The factors evaluated in that experiment were type of substrate degree of cure of the SMC type of adhesive consistency of bond-line thickness pattern used to apply the adhesive distortion in the inner panel temperature at which the adhesive was cured and type of electric bonding nest. Six factors were found to have a statistically significant effect on BLRT severity although the effect of three of the factors may have been confounded by an uncontrolled covariate. Two factors were found to not impact BLRT severity. The temperature at which the adhesive was fixture cured was found to be the factor with the greatest impact on B

The Use of Cohesive-Zone Models to Analyze the Behavior of Adhesive Joints

M.D. Thouless, September 2008

The use of adhesives in structural automotive applications will rely on an effective understanding of how they behave under crash conditions and how to model their performance. Historically the strengths of adhesive joints have been modeled by two distinctly different approaches-strength-based criteria and energy-based criteria. Cohesive-zone models form a natural and self-consistent approach to bridge these two approaches within a single framework. In systems for which the adherends remain elastic cohesive-zone models allow many well-known concepts of interfacial fracture mechanics and its energy-based failure criteria of toughness to evolve. In systems for which the adherends deform in a plastic fashion cohesive-zone models provide a framework for analysis in a regime that cannot be addressed by fracture mechanics. Under these conditions the behavior of a joint may be controlled by the strength of the adhesive the toughness of the adhesive or by a combination of the two parameters depending on the details of the geometry and properties of the materials. An practical issue is then how to determine in a relatively simple fashion the two cohesive parameters that can be used in mixed-mode applications. This is of particular interest for automotive applications where a methodology for designing adhesive joints for energy-management during crashes needs to be developed.

Renuva Soy-Based Polyol RIM for Automotive Exterior Applications

Dow Automotive & Magna/Decoma International, September 2008

There are many formative trends in today’s OEM composite marketplace which are driving the investigation and development of alternative feedstocks from natural or renewable resources in the plastics industry such as environmental sustainability reduced dependence on crude oil and the high cost of petroleum-based derivatives. This paper will describe the development of a novel soy oil based polyol (under the RENUVA™tradename) which has technological advantages in terms of odour physical properties compatibility and processability in polyurethane application over existing soy-based polyol. The paper will further describe the development partnership undertaken by The Dow Chemical Company and Polycon Industries (a division of Magna International) to utilize this “green” polyol to develop a Reaction Injection Moulded (RIM) polyurethane formulation suitable for painted exterior applications. The paper will outline the development aliterations done to accomplish this goal and to maximize the soy-based polyol content in the RIM composite for physical property and processability optimization. The paper’s conclusion will demonstrate the viability of a 50% soy-based polyol solution to meet the processability paintability and physical property specification of a current Original Equipment Manufacturer (OEM) RIM program through direct comparison of extensive trial work done on series production fascia tooling at Polycon. The paper will extend this development work into potential opportunities for the RIM polymer involving exterior composite applications for heavy equipment or agricultural machinery where natural resource feedstocks would have clear market desirability.

Banana Fiber Composites for Automotive & Transportation Applications

Lina Herrera-Estrada, September 2008

The purpose of this work was to establish and optimize a process for the production of banana fiber reinforced composite materials with a thermoset suitable for automotive and transportation industry applications. Fiber surface chemical modifications and treatments were studied along with processing conditions for epoxy and eco-polyester banana fiber composites. Flexural tests show that banana fiber/eco-polyester composites have a higher flexural strength and modulus due to improved fiber/matrix interaction. Environmental tests were conducted and the compressive properties of the composites were evaluated before and after moisture absorption. The resulting banana fiber/epoxy composites were found to yield a flexural strength of 34.99 MPa and compressive strength of 122.11 MPa when alkaline pretreated with improved environmental exposure resistance. While the non alkaline pretreated banana fiber/polyester composites were found to yield a flexural strength of 40.16 MPa and compressive strength of 123.28 MPa with higher hygrothermal resistance than pretreated fiber composites with the same matrix.

Chopped Glass & Natural Fiber Composites Based on a Novel Thermoplastic Epoxy Resin Matrix

Craig Chmielewski, September 2008

Composites of chopped glass and natural fibers based on a novel thermoplastic epoxy resin (TPER) matrix are introduced. Polymerization of substantially linear polymer chains based on epoxy resins produce an amorphous thermoplastic that is amenable to blending high loadings of reinforcing fillers which offer both high strength and stiffness. For example chopped glass fiber reinforced TPER composites offer similar room temperature tensile and flexural properties as glass filled polyamide 66 but are limited in their upper use temperature by TPER’s glass transition temperature of 90 °C. TPER is especially well suited to accepting high levels of natural based fillers such as wood flour and cellulose pulp. Natural fibers can be compounded into TPER at temperatures low enough to avoid thermal decomposition and yet result in composite mechanical properties of 3 to 4 times the flexural strength and 2 to 3 times the modulus of standard natural fiber-polyolefin blends. These new TPER based composites have properties and an appearance that make them candidates for a variety of automotive applications.

Natural Fibers Plastic Composites for Automotive Applications

Jay Amarasekera, September 2008

The use of natural fibers in composite plastics is gaining popularity in many areas and particularly the automotive industry. The use of natural fibers in polymers can provide many advantages over other filler technologies and areas of application appear limitless. The automotive industry is currently shifting to a “green” outlook as consumers are looking for environmentally friendly vehicles. Natural fibers are a renewable natural resource and are biodegradable which is an important characteristic for components that must be disposed of at the end of their useful life. They are recyclable and can be easily converted into thermal energy through combustion without leaving residue. Among the natural fibers with potential application as reinforcement for polymers curauá fiber is one that recently received special attention from researchers. Curauá is a plant from the Bromeliad family cultivated in the Brazilian Amazon region. The fiber is extracted from its leaves providing a high mechanical strength over traditional fibers like sisal jute and flax. We have developed thermoplastic composites using either curauá fiber or wood flour. These materials provided a lighter weight product with good physical properties and unique surface aesthetics. This paper reviews the properties of these bio composites in comparison with glass and mineral filled products. The products were tested in some automotive applications and the results will be discussed.

Case Study: Tough Low-Mass Class A SMC

Edward Zenk, September 2008

Fuel is one of the single largest expenses for fleet owners and it accounts for nearly 50 percent of a truck’s operating cost. Lowering a vehicle’s weight is a proven method of increasing operational economy whether in fuel consumption or additional capacity; and in the trucking industry this is a pressing need. A unique collaboration amongst a commercial fleet owner a heavy truck manufacturer and their suppliers achieved a cost-effective and significant weight savings through the use of tough low mass Class A sheet molding compound (SMC). This paper/presentation describes the customer’s objectives issues encountered and commercial results achieved with the new technology.

Introduction of Proven Marine Composite Process for the Commercial Vehicle Market

Fred Buck, September 2008

At Commercial Vehicle Group our drive for new and better processes and products never ends. One of our latest investments is in composite molding for interior and exterior trim components and systems. Through an exclusive agreement with VEC Technology LLC CVG is applying a composite closed mold process which has been used extensively in the manufacture of recreational boats to the unique needs of the commercial vehicle/heavy duty truck industry. The parts for heavy truck are very large in size while the part volumes are moderate and this situation presents interesting opportunities. Our molding process bridges the gap between the limitations of open-face molding and the higher costs associated with other forms of composite closed molding. In this presentation I will show you our Composite Molding Process from Concept and Design to the Mix Plant to the Application of Gel and Barrier Coats to the Laying of the Fiberglass to Molding & Part Creation to finally Routing Sanding and Application of Additional Parts with Structural Adhesive to the Customer.

An In Depth Study of Texture Characteristics & Their Affects on Texture Performance

Phil Maniscalchi, September 2008

Automotive and material suppliers have struggled for years with trying to produce quality textured hard plastic parts with correct gloss levels and good mar resistance. Many times suppliers are at the mercy of the textures being chosen by OEM design studios. Some textures that are visually appealing may not perform well for gloss and/or mar. In the past little was known as to what specific characteristics led to these performance limitations. The purpose of this paper is to identify the specific characteristics of automotive textures and how these characteristics affect mar and gloss on molded plastic parts. By analyzing these characteristics designers will be able to create or modify textures that are both robust and aesthetically pleasing. Topics to be discussed include identifying contributing texture characteristics discussing how these characters can be manipulated to improve performance and recommendations will be made as to how ideal textures should be developed in the future.

Rapid Manufacturing & Continued Development of Highly Stressed Fibre-Reinforced Plastic Parts: Motorbike Dash Assembly Made by Windform XT and SLS Technology

Stewart Davis, September 2008

The follow paper illustrates one of the latest high-tech RP and RM applications made by Laser Sintering Technology and WINDFORM® materials on a 125GP Honda racing motorbikes. In particular it describes the benefits coming from the use of WINDFORM material and the Rapid Manufacturing technology to produce a special Dashboard to host the motorbike’s electronic system developed internally by CRP Racing (the racing department of CRP Technology) which had to be light and stiff at the same time and above all the new design of the Dashboard support developed for the 2008 season in order to ease its substitution when crashed and saving some money as well. Completely different from the original one a new support was created in several modular parts to allow a good cost saving.

Film Transfer Technology Advancements for Composites

Ara Asadorian, September 2008

The composite industry has been driven to reduce the cost of composite parts. The Film Transfer Technology allows the manufacture to increase the value of manufactured parts. The Film Transfer Technology expands the manufacture's capability to coat protect and produce products with printed images during the production process. For example a manufacturer can immediately produce a wood grain panel at no capital cost. The Film Transfer Technology is applicable for SMC BMC Infusion and open mold manufacturing processes. The coating provides protection to the end product and image in chemical abrasive and outdoor environments. Thus the Film Transfer Technology increases the compostie manufacturer's capability to sell decorative products within the Marine Transportation and Architectural markets at a higher value.

NanoStructured Polymer Membrane for Fuel Cell Application: Computational NanoTechnology Approach

Seung Soon Jang, September 2008

We investigate a new molecular architecture in which water-soluble dendrimers are grafted onto a linear polymer for application to polymer electrolyte membrane fuel cells (PEMFC). Using computational nanotechnology we examined the nanophase-segregation and transport properties in hydrated membranes with this new architecture. In order to determine how the nature of the linear polymer backbone might affect membrane properties we considered three different types of linear polymers: poly (epichlorohydrin) (PECH) poly (styrene) (PS) and poly (tetrafluoroethylene) (PTFE). Each of these are combined with the second-generation sulfonic poly aryl ether dendrimer to form PECH-D2 PS-D2 and PTFE-D2. Our simulations show that the extent of nanophase-segregation in the membrane increases in order of PECH-D2 (~20Å)< PS-D2 (~35Å) < PTFE-D2 (~40 Å) at the same water content which can be compared to 30~50Å for Nafion and ~30 Å for Dendrion at the same water content. We find that the structure and dynamics of the water molecules and transport of protons are strongly affected by the extent of nanophase segregation and water content of the membrane. As the nanophase-segregation scale increases the structure in water phase the water dynamics and the proton transport approach those to those in bulk water. Based on the predicted proton and water transport rates we expect that the PTFE-D2 may have a performance comparable with Nafion and Dendrion.

Clay Nanotubes in Polymer Composites: A Route to Stronger Lighter & Less Expensive Materials

Cathy Fleicher, September 2008

Halloysite Nanotubes (HNT TM) provide a new avenue for the preparation of nanocomposites. Halloysite is a naturally occurring member of the kaolin family of aluminosilicate clays. Its uniqueness is that it exists predominantly in a tubular form with lengths of up to 10 microns and diameters of up to 400 nm rather than the layered platy form of essentially all other clays. Well-behaved dispersions of HNT in nylon-6 polypropylene TPO and several varieties of polyethylene have been obtained by standard melt processes. In all cases impr oved physical performance has been realized for molded parts. The result is a molded part that is more durable and lighter than a glass fiber reinforced counterpart. In addition injection molded HNT-containing composite parts exhibit improved surface appearance and reduced extrusion and molding cycle time relative to glass fiber containing composites. HNT have also been dispersed in polymer latexes and dispersions at quite high loadings. These polymer and clay dispersions have been coated and produce coatings with a tenfold increase in strength while maintaining transparency.

High Performance Plastic Components for Engine Mount Applications

Hans-Juergen Karkosch, Holger Klink, September 2008

In the face of dwindling resources rising energy prices and increasing environmental pollution reductions in consumption and emissions are topics of increasing importance in all fields of technology. To achieve these goals specifically in the automotive industry new engine concepts are needed in connection with thorough-going implementation of lightweight construction. Whereas weight-optimized plastics components are already utilized in many vehicle subsystems and components steel and/or aluminum structures are usually used for load-bearing structural elements. This statement also applies fundamentally for the engine mounting subsystem. In this area plastics components have been used previously only for subordinate moderately loaded semi-components. Now for the first time a mechanically highly-loadable torque reaction mount has been conceived as a plastics structural part and implemented in the series production of a vehicle with a transverse-mounted engine. In addition to weight reduction it also helps create a more advantageous load distribution on the axles. Load reduction on the front axle has positive effects on driving dynamics and safety. The paper begins by stating fundamental requirements for components of engine mounting systems. The principle procedure in developing load-bearing plastics components includes the topics of integrative simulation laboratory component tests and in-vehicle testing.

Development of a Structural Composite Underbody

Libby Berger, September 2008

The Automotive Composites Consortium is a joint program between General Motors Ford and Chrysler to develop structural automotive components from composite materials. A current Focal Project is a structural composite underbody capable of carrying crash loads with mass reduction of the vehicle structure a primary goal. Phase 1 of the project is the selection of a material and process system (M&P system). Three systems were evaluated each with several subsets. The selected M&P system is compression molding of sheet molding compound (SMC) with a vinyl ester matrix and predominately glass fabric reinforcement with some chopped glass. A high elongation core may be used to increase the integrity of the underbody after a crash event. This selection was based on mass and cost considerations including a technical cost model manufacturing feasibility and material properties of initial plaque moldings. CAE-based design methodologies were developed to achieve acceptable performance for full frontal frontal offset deformable barrier side and rear offset impact load cases. Body-in-white (BIW) static and modal stiffness and vehicle level crash performance and mass assessments were completed. Our current intent is to use weld bonding as the means to join the composite underbody to the steel passenger compartment. In support of this we have completed a CAE study of the weld bond model including an initial performance sensitivity study of joint geometry. Phase 2 of this project is underway with the goal of providing a full design of the underbody including design for durability and feasible scenarios for component manufacturing and vehicle assembly.

Machine Augmented Composites Utilizing an Hourglass Shaped Core Element in a Soft Nearly Incompressible Matrix

Roston Elwell, September 2008

Machine Augmented Composites (MAC) have small simple machines embedded in a matrix. MACs might provide materials with advantageous properties or new functions. Example properties are materials with increased damping or negative Poisson’s ratio. New functions might include the ability to change shape or to adjust stiffness. In the MAC material studied here the matrix is a soft polyurethane elastomer and the embedded machine is a nylon hourglass-shaped element. The desired improvements should give the composite material the ability to change shape and perform useful work. The hourglass core elements elongate as they are pressurized which actuates the structure. The elastomer matrix which is nearly incompressible aids the expansion. The commercial code ABAQUS was used to study the MAC’s deformation and to predict its response. Potential applications for this research in the automotive industry are in energy absorption and dissipation. Sandwich panels that change shape could increase driver and passenger safety by adapting the automotive body shell to road conditions or by damping noise and vibration. These panels might deploy like an air bag to absorb energy around passengers during an accident. Machine augmented composites are a promising field with potential to produce materials that serve as both structure and mechanism.

E-Coat Sustainable Long-Fiber Thermoplastic Composites for Structural Automotive Applications

Raman Chaudhari, September 2008

Polypropylene and glass fibre (PP/GF) based Long Fibre Reinforced thermoplastics (LFT) are nowadays established as state of the art materials for semi-structural applications in the automotive industry. However PP/GF LFT materials are limited for producing automotive components for use in general assembly. The use of LFT based components for structural applications and their implementation directly into the body in white assembly is still a challenge for the automotive industry. In order to develop LFT materials for such applications a feasibility study to investigate the e-coating process sustainability of LFT materials was conducted. The current article addresses the developed LFT formulations and their basic mechanical properties. For this purpose polyamide / glass fibre (PA/GF) based LFT materials were thoroughly investigated. The change of mechanical performance of the LFT materials due to applied temperatures of the e-coating process was investigated by benchmarking of non-temperature-treated against tempered LFT specimens. In addition the combined influence of temperatures and chemicals on the LFT properties was evaluated by running the LFT specimens through the actual painting line that included e-coating and subsequent painting and drying processes. Finally it was found that it is possible to manufacture LFT parts capable of withstanding the e-coating process without causing major changes in the performance of the LFT materials.

A Formulation Study of Long Fiber Thermoplastic Polypropylene (Part 1): The Effects of Coupling Agent Glass Content & Resin Properties on the Mechanical Properties

Creig Bowland, September 2008

The relationship between the resin and fiber properties in Polypropylene Long Fiber Thermoplastics is presented. The effects of glass content Maleic anhydride grafted polypropylene additives (coupling agent) and melt flow of the resin are presented. Various samples of Polypropylene Long Fiber Thermoplastics pellets (PP GLFT) were compounded with various coupling agent loadings and using different melt flow homopolymer polypropylene resins. The glass content of the pellets was varied from 30% to 50%. The pellets were then molded and tested for normal mechanical properties. The results of the study are presented.

New Methods to Produce Reinforced Polyamide-6 for Improved Material Properties in Engineering Plastic Applications

Ab van Geenen, September 2008

Polyamide-6 is widely used in many mechanical applications also in automotive replacing more and more traditional materials such as metals thermosets and elastomers. Good process ability along with outstanding physical properties also long term stability under tough conditions and a high value recycling ability make this thermoplastic material also commercial interesting for new demanding machinery parts. A broad variety of materials is achieved by producing PA-6 “in situ” by anionic polymerisation of Caprolactam which can be performed on extruders on RIM machines or in different casting processes. Nano-Clay or Glass fiber reinforced granules short or long-glass fiber reinforced molded parts glass-mat reinforced manhole covers or wind turbine blades are some examples of Brüggemann’s AP-Nylon® Material applications completed by NYRIM® the wide range impact modified grades. This paper gives an overview of the new developments in this field we were involved in during the last 2 years.

Lightweight Structural Parts with Rigid Integral PUR Foams

Stephan Schleiermacher, September 2008

With climate change and the current situation regarding energy and environmental policy dominating the agenda car manufacturers are faced with the complex problem of drastically lowering the fuel consumption of their vehicles in order to reduce CO2 emissions. One way of tackling the problem is to pursue a consistent strategy of lightweight construction. Self-activated as well as thermally activated rigid integral polyurethane foams from BaySystems can help to realise reductions in weight. They are ideal for use in structural parts. The presentation covers some of their state of the art solutions and techniques followed by a vision of a new composite design for roof modules which combines the aforementioned polyurethanes and their processing technologies with a sprayed polyurethane barrier layer.