SPE Library

A primary goal in automotive structures is reduction of weight while maintaining or improving other desirable attributes. Composite materials offer solutions to weight reduction in comparison to metal structures and thermoplastic composite materials offer the added benefits of improved cycle times high impact resistance cost-effective solutions and a path for sustainability. Developments in the area of injection over-molding of structural inserts produced from continuous-fiber-reinforced thermoplastics (CFRT ®) are an example of this and combine the advantages of injection molding with CFRT properties. Typical applications are in seat structures airbag housings front-end modules and crash beams that take advantage of the excellent strength and impact characteristics of the materials. A seat back application produced with injection over-molding of CFRT inserts is used as a demonstration case study.

More environmentally friendly composite materials for automotive manufacturing and building construction have been made by substituting coir fibers for the widely used polyester fibers to make non-woven fabric composites of coir fibers and recycled polypropylene fibers that can be compression molded into a wide range of parts or rolled into flat panels. This more environmentally friendly composite has a greater bending stiffness is more resistant to fire less expensive and without the odor problems that accompany many natural fibers.

Natural fibres such as flax hemp jute and wood are increasingly being used in various industries as reinforcing materials for composites to reduce weight cost and environmental impact. These fibres can have the added benefit of producing equal or higher stiffness-to- weight ratios than glass fibres. However processing natural fibres presents a number of challenges some of which are common to other types of fibres such as the ability to de-bundle mix and uniformly distribute them throughout the entire volume of a composite part. One particular challenge for natural fibres is the processing temperature limitations determined by their propensity to thermally degrade after long exposure times. This paper deals with the challenges of using biofibres as rein forcing materials for hermoplastic resins. The research work involves the use of short flax fibres in a continuous compounding process and flax fibres in the form of rovings and slivers in a Direct-Long Fibre Thermoplastic (D-LFT) process. The materials were compounded and moulded to produce parts for characterization. Polypropylene (PP) was used as polymer matrix because of its proven performance in automotive applications. Flax fibres were chosen given their combination of good mechanical properties availability and relative low cost compared to other bast fibres. Different formulations using heat stabilizers antioxidants and coupling agents were implemented with the objectives of preventing material degradation and improving bonding between the fibres and the thermoplastic material. Formulations with PP and 20% wt. discontinuous fibres showed an increment of up to 30% in tensile strength and 50% in tensile modulus when compared with virgin PP. Experiments using commercial flax rovings and slivers (continuous fibres) in conjunction with glass fibres (i.e. hybridizing of fibres) on an industrial large scale D-LFT line showed the viability of the processing technique for the manufacturing of hybrid reinforced the

This paper describes the recycling of automotive headliner postindustrial waste into useful composite panels. The process relies on granulating the waste blending it with a 100% solids VOC-free MDI isocyanate adhesive and thermally molding the mixture under pressure using atmospheric moisture as the curing agent.

Thermosetting plastics used today are not recyclable simply because they were never designed to be in the first place. However there is nothing inherent about the design of the plastics that precludes them from being re-designed to be recyclable/reusable materials. A general overview of recyclable epoxy technology is presented including the underlying chemical principles that enable recyclable epoxy and recyclable carbon fiber composites.

This presentation details how polyurethane spray sandwich technology originally developed for sunshades has been improved for use in more demanding applications such as load floors and parcel shelves. Polyurethane sandwich construction combines the low weight of a honeycomb core with the high strength of a fiber-reinforced polyurethane skin to produce load-bearing parts with very-high flexural stiffness and excellent thermal properties making it an attractive lighter weight alternative to ABS polypropylene sheet-molding compound (SMC) and wood products. Information on the deflection performance of different constructions with different systems including some with natural and some with glass mats will be given to guide manufacturers on the best ways to hit specific targets such as cost thickness or weight. Newer formulations enable productivity improvements including longer open times and shorter demolding times which facilitate production of larger parts and reduced scrap as well as feature higher bio-renewable content than previous versions.

Auto-rickshaws or motorized tricycle passenger taxis are a common form of transportation in India. These vehicles are often used at loads beyond specifications and under difficult road conditions. Part failures negatively affect earnings of the operators who play at the bottom of the economic pyramid. Use of bamboo fiber–epoxy composites has been nvestigated in these applications. The composites typically contain 30-40 wt-% fibers although loadings to 60 wt-% fiber can be used and fillers such as carbon black and fly ash can also be added. The composites exhibit tensile strengths of 140 MPa flexural strengths of 160 MPa and notched Charpy Impact strengths of 60 kJ/m2. These composites were subsequently molded into auto body parts (dashboarddoors and panels) and are under investigation with an auto-rickshaw manufacturer. Additionally helmets made with these composites were taken through drop tests similar to Snell Memorial Foundation Test Standards (ISO 17025 and American Association for Laboratory Accreditation A2LA). Bamboo-fiber composites positively impact the socio-economic health of the local community since bamboo is a renewable source it need not be chemically processed it reduces the petrochemical component of the composite and is known to help in waste-land reclamation and for combating soil erosion.

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.

The technical performance and sustainability value of natural fiber/thermoset acrylic composites has been demonstrated over the past few years. Recent development updates and further value-chain improvements in North America support further cost efficiency towards economical competitiveness. Local North American sources of natural fibers disconnected from Asian sources are now being established and offer greater reliability and affordability for the industry. New inline processing equipment to coat and dry nonwoven natural fiber or glass mat also has entered the market allowing for improved energy-efficiency and small production footprint plus higher quality process stability as well as other opportunities. The combination of these advances enables sustainable bio-composites that offer tremendous lightweight potential at competitive costs today.

This presentation provides a global overview of natural fiber composite materials and processes highlighting current research as well as the next generation of lightweight automotive interior substrates. It discusses both pros and cons of various lightweight sustainable substrate materials (including the wide family of resinmatrixed composites with an assortment of fibrous additives ranging from wood to flax) taking into account material suitability for automotive interior substrate applications. The goal of this talk is to encourage discussion of uses and benefits of natural wood composites to reduce weight and increase product sustainability.

Dow Automotive and Magna International have developed a polyurethane-based system to enable a novel sandwich structure that includes extensive use of environment friendly materials. This system addresses two significant challenges in the automotive industry: weight reduction and incorporation of renewable materials. An ideal application for this technology is the load floor an interior component located in the rear of the vehicle immediately above the floor pan. This paper will review the performance requirements for a load floor the alternative materials and the development of a novel sandwich structure solution which gives the best mass to load performance with the capability to tailor shape requirements and includes the use of environment friendly materials.

An ambitious multi-year program was recently undertaken in Europe to improve the sustainability of composites used in transportation – particularly with respect to the ability to develop thick parts with large surface areas economically. The program worked with a novel highly reinforced thermoplastic composite based on cyclic oligomers of polybutylene terephthalate (cPBT) which were used to produce thermoplastic prepregs that were then evaluated in vacuum bag processes while liquid cPBT / fiberglass systems were assessed in vacuum infusion and vacuum-assisted resin-transfer molding – all forming processes traditionally used for composites with thermoset (not thermoplastic) matrices. Once the best material / process combination for the program was determined and small-scale testing confirmed the finished composite provided sufficient mechanical performance the prepreg / vacuum bag process was selected to mold one of the largest thermoplastic parts ever produced: a 3-piece structural floor for a flat-bed trailer for a Class 8 truck which is the focus of this paper.

Thermoplastic composite laminates can be post-manufactured by progressively thermoforming them to generate contoured parts from prior flat panels. This process is attractive for expanding the potential usage of composite materials in next generation transportation infrastructure marine and military sectors for part replacement and structural applications. Thermoforming has proven to be an efficient means for creating parts of complex geometries. Accurately predicting material properties and temperatures prior to forming is of utmost importance to minimize waste and reduce cost for mass-production applications. This paper presents a finiteelement modeling approach to establish the manufacturing parameters for locally formed thermoplastic composite plates.

Distillers grain a by-product of the ethanol process has been used to produce thermoset and thermoplastic polymers that can replace a portion of and/or enhance traditional petroleum-based resins in various plastics manufacturing processes. The process results in unique characteristics and allows inclusions into finished plastics products at rates of up to 40% final bio content. The pellets produced are consistent with the standard feedstock materials used by plastic manufacturers in thermoplastics and currently are being tested with polypropylene (PP) and polyethylene (PE) and the bio-based polyhydroxyalkanoate (PHA) and polylactic acid (PLA) resins in some applications. Trials are underway in injection molding rotary molding and extrusion molding. Test results have indicated improvements in some properties of finished goods with good processing characteristics when run at temperatures below 193C. Further testing in thermoset bulk-molding compound (BMC) has resulted in lower specific gravity while retaining physical properties and good surface finish.

Automotive engineers are looking for options to reduce weight and increase engine efficiency to comply with new CO2 emission and fuel economy regulations. As a consequence under-the-hood operating temperatures continue to increase. Engineering thermosets are an effective lightweighting alternative to heavier conventional steel and aluminum die-cast products. They combine outstanding temperature stability long-term mechanical strength dimensional stability and high chemical resistance. This presentation focuses on 2 recent automotive underhood applications where phenolic-based engineering thermosets successfully replaced traditional metals. First a thermoset water pump housing was shown to outperform cast aluminum in dimensional stability while lowering overall weight; and a thermoset vacuum pump also originally designed in die-cast aluminum provided high mechanical strength and improved dimensional stability at reduced cost and weight. Finally various recycling methods for these thermoset materials are described.

Biocomposites are recent advancements used to develop cost-effective sustainable materials for numerous applications in response to the mounting needs to find substitutes for polymers based on fossil fuels. Polylactic acid (PLA) is an aliphatic and is the most promising in the bioplastics’ family although its use can be constrained by its poor mechanical properties lower thermal stability and processing difficulties. The objective of this research was to investigate and improve mechanical and thermal properties of PLA by developing PLA composites reinforced with hemp natural fibres results of which are discussed in this presentation.

Addition of graphene oxide enhances the elasticity, stiffness, and tensile strength of phenolic resin, and improves its heat stability by nearly 30°C.

Starch-based biocomposite films incorporating spherical cellulose nanocrystals from garlic stalks offer a novel application of an underused natural fiber.

Semi-crystalline terpolymers prepared from L-lactide, trimethylene carbonate, and glycolide are promising materials for cardiovascular stents.

Using natural fatty acids to treat the cellulose components of green composites reinforced with agro-waste fibers reduces their water uptake resulting in stable and environmentally friendly materials.