Spinning Chopped Fiberglass Scrap into Continuous Technical Yarns for Reuse
Lead:
University of Tennessee, Knoxville (UT)
Partners:
TPI Composites
Cost share:
IACMI: 65%
Industry: 35%
Duration:
September 2024 – March 2025
Problem statement:
The overwhelming majority of fiber reinforced polymer composites are made with fiberglass reinforcement. Fiberglass’s near ubiquity means that large quantities of fiberglass manufacturing waste are generated and landfilled every year.
Project goal:
Previous demonstrations with recycled end-of-life fiberglass showed that it is possible to take discontinuous fiberglass and spin it back into continuous technical yarns. In this project, the team proposed to adapt its fiberglass yarn spinning technology for the conversion of manufacturing waste into continuous technical yarns for added value products. This conversion back into a robust continuous form factor enables fiberglass reuse for many new, previously impossible high value, high throughput applications.
Technical approach:
- Produce fiberglass yarns with up to 50 wt% manufacturing waste as an input feedstock target (25 wt% as a minimum) comingled with acrylic and/or phenolic staple fibers
- Produce plied yarns with nominal linear density of 2000-4000 tex at least 200-300 yards in length
- Demonstrate yarn suitability for composites manufacturing by running pultrusion trials for a 100mm wide electric vehicle (EV) battery separator component
Conclusions:
- This project has demonstrated that it is physically possible to mechanically recycle fiberglass production scrap into new hybrid yarns for reuse in some manufacturing contexts, eliminating waste and yielding more product.
- Successful pultrusion with the 1.8 mm thick die used in this project suggests promise for wider applications with thicker cross-sections and greater recycled material content.
- Successful pultrusion with phenolic suggests the recycled yarn should also work with easier resin systems (e.g., polyester, vinylester)
- Materials recovery and circular application reuse via yarn production yielded an attractive recovered content to cost increase ratio of 3.2 wt% : 1% cost, which suggests potential economic viability in applications such as automotive.
- Within the context of the specific target application in this project, it was estimated that yarn reuse could potentially be used to produce ~225,000 EV battery enclosures with a current market value of ~$270MM.
Recognition:
CAMX 2022 Ace Award for Market Growth: Composites Sustainability (initial demonstration)
Potential Impact:
If this technology could be made to work for readily available manufacturing glass waste and a growing market demand established, the resulting market pull could provide the outlet necessary to justify the capital expenditure to begin end-of-life composites recycling.