CompositesWorld
Issue link: https://cw.epubxp.com/i/697353
JULY 2016 6 CompositesWorld Recycled fiber supply base The supply base for discontinu- ous milled and (left) chopped fbers and longer fbers and fber forms is established and growth-capable. The missing piece is demand. Source | ELG Carbon Fibre Ltd. Table 1 Recycled CF in reinforced thermoplastic compounds Recycled carbon fber exists in forms that are suitable for use by compounders (milled and chopped fbers in powder or pellet form). Source | Albis (UK) Ltd. COMPOSITES: PAST, PRESENT & FUTURE » Te carbon fber industry has changed a lot in the past 15 years. In 2000, the global market for carbon fber was less than 20,000 MT. Now, it is greater than 60,000 MT per year, and fore- casts indicate this will increase to between 100,000-140,000 MT, annually, in the early 2020s. Te impressive growth that we've seen already — and that we expect to continue — puts a new emphasis on the role of carbon fber recycling in the development of the industry. Te process from manufacturing carbon fber to production of fnished components is wasteful; it is estimated that more than 30% of produced carbon fber ends up as waste at some point in the process. Where the carbon fber composites industry most difers from other industries that produce high proportions of waste is that it lacks an efective recycling solution. Tis is not to say that we cannot recycle carbon fber. ELG Carbon Fibre is one of several compa- nies that have developed cost-efective means of recovering carbon fbers from manufac- turing waste and end-of-life components without signifcantly degrading fber properties. But there are signifcant barriers to returning reclaimed fber materials to the market. To understand why, we need to briefy recap the current status of recycled carbon fber materials. Today, recycled products exist in forms that are suitable for use by compounders (milled and chopped fbers in powder or pellet form) and in composite layups (nonwoven mats as dry fabrics as well as prepregs and SMC mate- rials), as shown in Tables 1 (at right) and 2 (p. 8). However, the use of these products outside of R&D; projects is, thus far, very limited. Te major barrier that must be overcome is one faced by all new materials — lack of knowledge about mechanical properties and processing characteristics, and lack of large-scale demonstra- tors that prove the economic, technical and environmental justi- fcation for using these materials. Although there are a number of projects that are addressing these issues, the push from the manu- facturing side of the supply chain to fnd a solution to its carbon fber waste problem generally isn't matched by a pull from the supply chain's design side to fnd ways of using recycled carbon fber products. To date, the most successful demonstration of recycling has been BMW's (Munich, Germany) use of reclaimed carbon fber materials in its i3 and 7-Series models, in which manufacturing waste from dry fber processes has been converted into new product forms and used in closed-loop recycling solutions. Tis was greatly facilitated by the integrated supply chain that BMW and SGL Group (Wiesbaden, Germany) established. If such integrated supply chains don't become the norm in future, then it is vital that all elements of a supply chain work closely together not only to develop methods of recycling carbon fber, but also to get recycled carbon fber products back into the supply chain. Why should we do this? From an economic standpoint, recycled carbon fber products can reduce the cost of lightweighting, used either on their own or in conjunction with virgin carbon fbers. In fact, making lightweighting strategies afordable must be a primary goal if we are to see increasing use of carbon fber in high-volume applications. If we address this challenge, then we can increase Impressive industry growth puts a new emphasis on the role of carbon fber recycling. Recycled carbon fber: Its time has come Comparison of Reinforced Thermoplastic Compounds Reinforcement 30% Glass Fiber 10% Virgin Carbon Fiber 10% Recycled Carbon Fiber Density (gcm -3 ) 1.38 1.21 1.17 Flexural Strength (MPa) 259 223 232 Young's Modulus (GPa) 9.0 10.3 10.3