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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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
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
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
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.
O. Khondker, U.S. Ishiaku, H. Hamada, September 2003
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.
Asami Nakai, Dai Nakaami, Tsutom Narita, Hiroyuki Hamada, Eisuke Fukui, September 2003
In this study multi-axial warp knitted thermoplastic composites were fabricated by our-developed Micro-braiding technique. Cross-sectional observation tensile test and 3 point bending test were performed. The composite with good impregnation state and high mechanical properties was obtained under appropriate molding conditions. The multi-axial warp knitted fabric composite without unimpregnated region had the
equivalent mechanical properties with unidirectional composite laminates. From these results continuous fiber
reinforced thermoplastic panel was realized by combining braiding and knitting technique.
Sharad Kumar, Krishnamurthy Jayaraman, September 2003
The effects of specific functionalization of montmorillonite clay on the mechanical properties of melt-processed PP/clay nanocomposites have been investigated with three different clays. Organically modified montmorillonite was subjected to appropriate silane treatment in order to functionalize the edges. Each of the
organoclays was compounded with a maleated polypropylene (PP-g-MA) and a PP in the proportion 5:10:85 by wt. The clay silated in this work was confirmed by XRD to be edge functionalized. This clay led to the composite with the greatest level of exfoliation as determined by both XRD and dynamic viscosity measurements. The same composite also had the highest tensile modulus. However the flexural modulus was found to be insensitive to additional treatment of the clay. Hence the increase in tensile properties reflects the greater extent of dispersion as well as a higher degree of orientation achieved during molding.
Printout on the surface of an FRP laminate has one primary source: resin shrinkage. The very property that makes polyester resin with glass reinforcement so durable is its own enemy when surface appearance is an issue. During the curing stage of a laminate resin shrinks and glass goes not shrink. A surfacing veil added to a lamination schedule will dramatically reduce the resin shrinkage at the surface giving it a smooth and consistent resin-rich surface. A consistent resin-rich surface in the composites industry includes a corrosion barrier UV barrier a smooth finish and lower porosity. Surfacing veil added to a process can also increase efficiency including quicker resin flow in closed-mold situations earlier demold time protecting pultrusion dies strengthening the gel coat and bonding the gel coat to the reinforcement.
In the automotive industry’s incessant drive towards higher performance lightweight materials there has been much interest in the area of carbon fibres (CF) as a potential filler solution for thermoset composite materials. RRIM (Reinforced Reaction Injection Moulded) composite materials have been successfully used in automotive exterior applications such as fascia fenders claddings and truck sides for over 25 years now and have developed a reputation for offering durability functional performance design freedom and paintability to the OEM. These RIM composites have traditionally incorporated glass wollastonite or mica as high performance fillers for these applications which have a relatively high specific gravity of 2.5-2.9. The benefits that carbon fibre’s high strength-to-weight ratio and lower density could bring to the RIM polymeric network was the primary focus of this study. This paper will explore the use of carbon fibres in RIM polyurethane/polyurea composites as an opportunity to reduce weight and will explore the characteristics of the resultant composite. The paper will provide an evaluation of the performance of the carbon fibres from a perspective of processability mouldability physical properties paintability and functional part manufacture in the area of automotive exterior body panels such as fenders or quarterpanels. The study will touch upon the benefits that the developed carbon fibre composites can bring to the industry - such as light weight a relatively high stiffness-to-weight ratio a good balance of physical properties and increased electrical conductivity for improvements in paint transfer efficiency and aesthetics. The study will also discuss some of the considerations that working with carbon fibres will likely entail such as higher raw materials cost and processability limitations.
Lanhong Xu, Tom Mase, Lawrence Drzal, September 2003
Free radical cured thermosetting vinyl ester resins have superior toughness and chemical resistance in comparison to unsaturated polyester. The use of vinyl ester composites reinforced with carbon fibers requires an improvement in the fiber-matrix adhesion levels. Previous data has shown that the application of a lightly cross-linked amine-cured epoxy sizing to the carbon fiber surface creates a beneficial interphase between the carbon fiber and vinyl ester resin matrix resulting in a substantial increase in fiber-matrix adhesion and the sizing has a optimum thickness . However the exact mechanism by which this coating improved adhesion is not known. Vinyl ester resin can undergo as much as 10% volume shrinkage with cure while typical epoxy systems undergo only 3-4% shrinkage during cure [4-6] . The cure volume shrinkage could have induced significant stresses in the fiber/matrix interphase. This could be the one of the most important factors that lowers the adhesion between carbon fiber and vinyl ester resin. In this study the influence of the matrix cure volume shrinkage on the adhesion between carbon fiber and vinyl ester resin was investigated. Adhesion was evaluated as interfacial shear strength (IFSS) measured with a micro-indentation. Finite element analyses were used to simulate stress at the interphase and matrix as well after matrix shrink. It was found that cure volume shrinkage of vinyl ester could introduce thermal residual interfacial tensile stress which would decrease the adhesion between fiber and matrix the greater the shrinkage the more significant the effect. The cure volume shrinkage was dependent on the molecular weight of the vinyl ester monomer and content of styrene content and also is related to the cure process and catalysts for polymerization. It was also found that a specially formulated epoxy-sizing which swells in a vinyl ester matrix could counteract the cure volume shrinkage of the matrix. The results from finite element analyse
Hiroyuki Fukushima, Lawrence Drzal, September 2003
Many research efforts have been focusing on exfoliated clay systems the same nanoreinforcement concept can be applied to another layered material graphite. The key to utilizing graphite as a platelet nanoreinforcement is in the ability to exfoliate this material. If the appropriate surface treatment can be found for graphite its exfoliation and dispersion in a polymer matrix will result in a composite with not only excellent mechanical properties but electrical properties as well opening up many new structural applications as well as non-structural ones where electromagnetic shielding and high thermal conductivity are required. In this research a special thermal treatment was applied to the graphite flakes to produce exfoliated graphite reinforcements. Intercalated natural crystalline graphite compounds [GICs] were formed followed by exfoliation and milling to produce sub-micron graphite flakes. SEM and TEM images showed that the average size of graphite became 0.86 um with a thickness of around 5 nm. With the proper surface treatment the graphite nanoplatelets in polymeric matrices showed better flexural strength than composites with other carbon materials. Impedance measurements have shown that the exfoliated graphite plates percolate at below 3 vol% and the composites showed resistivity close to 101ohm*cm. The cost of this new nano-size graphite material was estimated to be around $5/lb or less. Since exfoliated graphite has superior mechanical electrical thermal properties and cost effectiveness this material has been shown to be a superior potential reinforcement for polymer nanocomposites for many applications including fuel cells batteries and composites for electrical shielding.
The 2002 Aston Martin V12 Vanquish is one of the most technically advanced cars on the road. From its extruded aluminum space-frame to its carbon fiver transmission tunnel and energy absorbing crash structures the entire vehicle is adhesively bonded together. Several adhesives are used throughout the structure to optimize performance and processing. A toughened single component epoxy adhesive is used to bond the aluminum extrusions whereas a low modulus two-component polyurethane adhesive is used to bond the aluminum extrusions whereas a low modulus two-component polyurethane adhesive is use to attach the glass fiver composite body panels. The structural composite parts such as the front crash structure and tunnel are bonded using a medium level modulus two-component polyurethane adhesive. This paper will outline the role of adhesives within the Aston Martin V12 Vanquish in particular the bonding of the twenty plus composite parts. Details of the adhesive selection corrosion durability and manufacturing issues will be presented for the front crash structure assembly.
A. Droste, P. Naughton, B. Bowser, J. Rottger, S. Burr, O. Imam, M. Zeitler, T. Heuft, A. Cawley, September 2003
With continued increases in energy costs
the trend towards weight reduction and
fuel economy in the automotive industry
will further grow in importance in the
coming years. However increased safety
and performance are demands on which
the consumer is also not willing to
compromise. This paper presents a viable
technology complimentary to metals for
structural applications where stiffness
impact resistance and functional
integration are combined to form a cost
effective lightweight solution. The paper
examines the use of metal-plastic
composite structures as a means to
reduce weight while maintaining or
improving performance. The metal is used
where the high stiffness and strength can
be exploited while the plastic composite
gives a balance of stiffness and impact
resistance and enables functional
integration through the formation of
complex shapes in the moulding process.
The combination allows the optimisation of
the performance and function per unit
weight of the application by balancing the
contribution of the metal and the plastic
Polypropylene (PP)-based composites
have high potential for usage in many
structural applications in cars due to the
cost effectiveness combined with a good
balance of properties. The availability of
the matrix material and the extensive
manufacturing capabilities globally for PP
composites make this an obvious choice
for a broad range of OEMs and
When the merits of this approach are
accepted the question remaining is how to
combine these two dissimilar materials.
This paper shows the benefits of the use
of adhesives which greatly reduce stress
concentrations and spread the load
compared to mechanical fastening
allowing a more efficient use of materials.
The choice of adhesive is discussed in
combination with the plastic and metal
used. When plastics with low energy
surfaces are used such as polypropylene
several process steps are required to
achieve an effecti
Kenichi Sugimoto, Akihiro Ochi, Asami Nakai, Hiroyuki Hamada, September 2003
In this paper the effect of stacking sequence and
laminate thickness on mechanical behavior of matrix
hybrid composite with mechanical joint was
investigated to improve the performance of composite
structures for automotives. Four types of stacking
sequences of matrix hybrid and two kinds of laminate
thickness were prepared. The failure maximum load
depended on the characteristic of matrix resin and
laminate thickness. The optimum stacking sequence
especially in case of thick laminate was expected by
placing conventional resin that is rigid resin into outer
domain and flexible resin into inner domain.
Class 8 trucks offer substantial opportunities for weight reduction with cost incentives resulting from increased payload and improved fuel efficiency. The chassis suspension drive train and wheels contribute to approximately 40% of the truck weight and have components that are excellent candidates in terms of material performance requirements for replacement with low-density structural composite materials. However actual or perceived deficiences in joint reliability have up to now limited use of polymer composites in this application. Researchers at Oak Ridge National Library (ORNL) and Pacific Northwest National Laboratory (PNNL) have begun a project to overcome the major technical issues associated with joining thick fiver-reinforced composite sections. The initial objective is to develop both economical and robust attachment techniques for composite members joined to steel members. The research will be coordinated with an industry team led by Delphi Corporation that is developing and commercializing composite chassis members through funding from the Department of Energy's (DOE's) High Strength Weight Reduction Materials Program under the Office of FreedomCAR and Vehicle Technologies.
Fiber reinforced polymers (FRPs) are promising materials for reducing vehicle mass thereby improving energy efficiency and US energy security. Presently the cost of using FRPs especially with carbon fiber reinforcement is quite high in comparison to conventional materials and the lack of market incentives prevents their widespread use in passenger automotive structures. Furthermore the material demand from even a small passenger automotive carbon fiber reinforcement application would overwhelm the carbon fiber reinforcement application would overwhelm the carbon fiver supply chain. The Class 8 truck market offers modest financial incentives for vehicle mass reduction in some sectors and vehicle build rates are low enough that the composites industry can satisfy demand without making step changes in capacity. This suggests that a rational strategy for realizing the energy efficiency benefits of low mass composite materials in the transportation market is to develop and initially demonstrate new technology in the commercial vehicle market with migration into the passenger automotive market as the technology matures. The US Department of Energy's (DOE's) FreedomCAR and Vehicle Technologies Office is therefore funding a significant research and development effort focused on heavy truck applications.
Ravi Mayavaram, Mahender Reddy, David Stewart, John Tolle, September 2003
A novel approach to optimize mold cooling using a seamless combination of simulation and optimization tools under a unified framework is presented. Heat transfer in the mold is modeled using a transient heat conduction equation with appropriate source/sink terms. Crystallization kinetics and the latent heat contribution of the polymer are also considered. Cooling passages are modeled exactly in three dimensions and also using one-dimensional cooling circuits. The latter method is used to accurately specify the heat transfer boundary conditions in the passage by separately computing the coolant flow. The keys to this modeling approach are the data structure that represents the problem domain and the interface between the solver and optimization tool. The simulation is designed specifically with optimization in mind. A sample analysis and results highlighting the methodology is presented in this work.
Allen Peng, Yorker Chang, Anthony Yang, Venny Yang, Fu Chin Chuang, September 2003
A lot of automobile plastic parts are made of fiber-reinforced engineering plastic for its superios mechanical properties and high heat distortion temperature. The fiber orientation and anisotropy shrinkage in injection molding are complex 3D phenomena. They are difficult to identify and stufy by the traditional 2.5 D model. The thermal and mechanics properties of the composite closely relate with the fiber orientation pattern. Thermal shrinkage is larger in transverse direction and lower in fiber orientation direction. This 3D technique is proved to be a powerful tool for the study of 3D fiber orientation and anisotropy shrinkage phenomena and a cost-effective approach for related part/mold designers.
Manufacturing of structural metal parts directly from computer aided design (CAD) data has been investigated by numerous researchers over the past decade. Researchers at NASA Langley Research Center are developing a new solid freeform fabrication process electron beam freeform fabrication (EBF3) as a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Thus far this technique has been demonstrated on aluminum and titanium alloys of interest for aerospace structural applications; nickel and ferrous based alloys are also planned. Deposits resulting from 2219 aluminum demonstrations have exhibited a range of grain morphologies depending upon the deposition parameters. These materials have exhibited excellent tensile properties comparable to typical handbook data for wrought plate product after post-processing heat treatments. The EBF3 process is capable of bulk metal deposition at deposition rates in excess of 2500 cm3/hr (150 in3/hr) or finer detail atlower deposition rates depending upon the desired application. This process offers the potential for rapidly adding structural details to simpler cast or forged structures rather than the conventional approach of machining large volumes of chips to produce a monolithic metallic structure. Selective addition of metal onto simpler blanks of material can have a significant effect on lead time reduction and lower material and machining costs.
Rapid tooling processes have traditionally been limited in application to relatively small components. The Zoned Tooling (Z-Tool) process differs from other technologies in that it utilizes forged plate stock as its raw material and can be used to manufacture even the largest of automotive molds. Utilizing knowledge based programming features within a CAD environment a tool is sectioned into a number of segments (zones) that are then rough cut with a waterjet or milling machine and electron beam welded into the final form. Traditional roughing and gun-
drilling are eliminated and finish machining and subsequent processes proceed in the normal manner. The challenges and advantages of the process are discussed along with a demonstration of a typical application.
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Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
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Society of Plastics Engineers
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