Neues System für das Recycling von Polyacrylnitril(PAN)-haltigen Textilabfällen

  • New system for the recycling of textile waste containing polyacrylonitrile (PAN)

Schriever, Sascha Georg; Gries, Thomas (Thesis advisor); Seide, Gunnar (Thesis advisor)

Düren : Shaker Verlag (2020)
Book, Dissertation / PhD Thesis

Dissertation, RWTH Aachen University, 2019

Abstract

The aim of this work is to develop and investigate a new system for recycling textile waste containing polyacrylonitrile (PAN). In this thesis, a process chain was developed which is divided into the following sub-processes: •Mechanical pre-conditioning of the wastes •Recovery of PAN as polymer •Production of spinning solutions from recycled PAN •Spinning recycled PAN fibres. For mechanical pre-conditioning of PAN-containing textile wastes, the cutting mill with 40 mm discharge sieve is best suited from the validated comminution aggregates. During recovery of the PAN polymer, it could be recycled as pow-der or granulate and partially freed from impurities (sizing and finishing agents). Furthermore, the molecular weight distribution becomes more pronounced com-pared to virgin PAN, the PDI decreases from 2.2 to 2.0. The recycled PAN was processed into spinning solutions with virgin PAN added and spun into recycled PAN fibres in a wet spinning process. It shows that the strength of the recycled PAN fibres loses strength and elongation as the recycled amount increases. Accordingly, a fineness related strength of 21.8 cN/tex is achieved for the internal benchmark, which decreases to 17.5 cN/tex at a recycling rate of 100 %. With a 10 % increase in the recycled content, the fineness related strength decreases by 0.45 cN/tex, which corresponds to 2.1 %. Within the scope of a subsequent economic feasibility analysis, the manufacturing costs for recycled PAN fibres amounted to 1.836 €/kg, the cost price was 2.574 €/kg, whereas the target price for an industry standard is 1.95 €/kg. For realistic payback times between 2 and 5 years, the recycled PAN fibre must be sold for between 3.10 €/kg and 3.90 €/kg.

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