Abstract
Most recycling methods remove the essential sizing from reinforcing fibres, and many studies indicate the importance of applying sizing on recycled fibres, a process we will denote here as resizing. Recycled fibres are not continuous, which dissociates their sizing and composite lay-up processes from virgin fibres. In this study, commercial polypropylene and polyurethane-based sizing formulations with an aminosilane coupling agent were used to resize recycled glass and carbon fibres. The impact of sizing concentration and batch process variables on the tensile properties of fibre-reinforced polypropylene and polyamide composites were investigated. Resized fibres were characterized with thermal analysis, infrared spectroscopy and electron microscopy, and the tensile properties of the composites were analysed to confirm the achievable level of performance. For glass fibres, an optimal mass fraction of sizing on the fibres was found, as an excess amount of film former has a plasticising effect. For recycled carbon fibres, the sizing had little effect on the mechanical properties but led to significant improvement of handling and post-processing properties. A comparison between experimental results and theoretical prediction using the Halpin-Tsai model showed up to 81% reinforcing efficiency for glass fibres and up to 74% for carbon fibres.
| Original language | English |
|---|---|
| Article number | 5773 |
| Pages (from-to) | 1-15 |
| Number of pages | 15 |
| Journal | Materials |
| Volume | 13 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - 2 Dec 2020 |
| MoE publication type | A1 Journal article-refereed |
Funding
This project was funded by the European Union’s Horizon 2020 research and innovation programme Large scale demonstration of new circular economy value-chains based on the reuse of end-of-life fiber reinforced composites—FiberEUse (grant number 730323) and Academy of Finland postdoctoral project From micro-scale data to macro-scale understanding for improved safety of composite materials—MicMac (grant number 314983).
Keywords
- Carbon fibres
- Glass fibres
- Recycling
- Surface treatments
