# Opportunities and Limitations in Recycling Fossil Polymers from Textiles
## Recycling Fossil Polymers
### Acrylic  
Acrylic fibres are synthetic fibres made of at least 85% of acrylonitrile monomer with other comonomers, typically vinyl acetate or methyl acrylate, to obtain a final fabric with different characteristics. Acrylic fibres are used for sweaters, pants, hoodies, and a variety of other types of cold-weather clothing. Additionally, acrylic is a popular material for carpeting, upholstery, rugs, and other traditionally wool-dominated homeware product categories. It is estimated that, every year, in Europe, about 7700 tons of acrylic textile waste are disposed of by landfill or incineration. Polyacrylics can be mechanically recycled, comparable to wool. The process involves colour sorting, cleaning, unravelling and spinning again [111]. Polyacrylics cannot be melted, and although they can be dissolved, presumably no physical recycling methods are under development. Polyacrylics are formed by addition polymerisation and can therefore not be depolymerised by solvolysis methods.  
Being extremely durable and able to repel water, acrylic fabrics are the most used for outdoor avnings and patio furniture. However, to have the required characteristics for such use, it is necessary to apply chemical finishes to the acrylic fabrics to increase the hydro and oil-repellency, the resistance to UV and to fire. This makes the management of acrylic textile waste tricky. The EU-funded REACT project [111] aimed to identify possible processes to treat and recycle textile waste in an ecological and economic way. In this project, a method was developed to remove unwanted substances (fluorocarbons, melamine and acrylic resins, anti-mold agents) from the waste of acrylic fabrics with an environmentally friendly process to improve recycling, to improve sustainability and reduce the risk to the environment and to health. After elimination of the finishing chemical, the mechanical recycling and spinning permit the reuse of acrylic fabrics as raw material for other production cycles, also in combination with virgin fibres.  
Pyrolysis of waste acrylic textile between 500 and 800 \({}^{\circ}\)C and the steam activation of the chars begin the production of activated carbon [112]. A mechanical recycling approach was attempted to prepare non-woven panels by using a needle-punching method [113] or to fill the recovered acrylic in between a double wall for thermal insulation in buildings [114].  
Recently, carbon fibres were prepared in the laboratory from textile grade polyacrylamide (PAN) fibres thanks to a systematic investigation into the stabilization and carbonization of textile-grade PAN fibres [115]. The tensile properties of carbon fibres from textile-grade PAN fibres were found to be comparable with those of commercial PAN fibres. Thus, textile-grade PAN precursor can be an indispensable candidate for low-cost carbon fibre production, and this process would represent in the future an interesting up-cycling option. After all, the strong interest in this approach is testified to by the production of carbon fibres starting from cotton [116] and cotton/polyester mixtures [117] recently being investigated as well.