Green composites: Chicago compounder introduces recycled CF-reinforced PA 6/6

At the 13^th annual Automotive Engineering Plastics Conference (AutoEPCON) organized by the Society of Plastics Engineers (SPE, Bethel, CT, US) and held in the Detroit suburbs on April 30-May 1, a Chicago-based custom compounder and distributor debuted an interesting new pelletized carbon fiber-reinforced thermoplastic composite.

The material, called FiberX2 from JM Polymers (Chicago, IL, US), is notable because it uses both recycled carbon fiber (CF) from the aerospace and sporting goods industries (post-industrial and post-consumer recyclate (PIR, PCR)), plus PIR polyamide 6/6 (PA 6/6) resin from the automotive industry. The combination makes the new product as well as parts made from it greener because it takes significantly less energy to collect, clean, and repurpose both fiber and resin than it does to make virgin (prime) fiber and resin. In addition to a lower carbon footprint, companies save additional green thanks to a 15-20% cost reduction vs. prime resins with the same fiber length and loading levels. The company also says the product offers 1.5- to 1.8-times better tensile strength than long-glass fiber polypropylene (124 MPa for 50% LFT-PP vs. 184 MPa for 20% CF-PA 6/6).

FiberX2 is initially being offered with 20-, 30-, and 40% CF reinforcement. Interestingly, 30% seems to be the sweet spot, as data comparing tensile strength values for virgin CF-PA 6/6 of the same fiber length and loading levels shows that values are the same at 30% loading (both 221 MPa) whereas they are slightly lower at both 20% (184 vs. 190 MPa) and 40% (221 vs. 234 MPa). Similarly, when comparing flexural modulus, the recycled compounds have slightly higher bending stiffness than prime except at the 20% level. The company says it tweaks its own sizing to assure good bonding to polyamide.

According to Josh Ullrich, JM Polymers president and CEO, the company began working with Ford Motor Co. (Dearborn, MI, US) in 2014 to develop the product, and they currently are working on several developmental projects at the automaker and to get specified. The company next plans to introduce a grade that is reinforced with 15% fiberglass and 5% carbon fiber. That product will offer slightly better impact and lower cost than the all-carbon grades, albeit at lower stiffness and strength. “As a custom compounder, we’ve got the ability to tweak our formulations to meet customer requirements, such as when they need to hit a particular shrinkage or impact target,” adds Ullrich.