Depolymerization Mechanism
Chemical depolymerization of polyethylene terephthalate using ethylene glycol converts post-consumer polyester textiles back into soluble monomeric units. Utilizing glycolysis recycling allows manufacturers to reclaim synthetic fibers from blended garments and dye-heavy apparel. This reaction breaks the ester bonds of the polymer chain, resulting in bis(2-hydroxyethyl) terephthalate.
Polymer Synthesis
Catalytic execution requires temperatures between one hundred and eighty and two hundred and twenty degrees Celsius under atmospheric pressure. Metal catalysts accelerate the reaction, enabling the glycol to break down the polyester chips or fabrics within a few hours. The resulting solution is then filtered to remove insoluble impurities such as elastane fibers and buttons, yielding a high-purity monomer stream suitable for high-performance spinning.
Quality Evaluation
Purified monomers are subsequently repolymerized into recycled polyester yarn that exhibits the same physical characteristics as virgin fiber. This high-grade material avoids the downcycling common in mechanical processes, which shorten the fiber length and reduce fabric strength. Spun fibers produced through this method can be dyed and finished without any aesthetic compromises.
Process Comparison
Commercial feasibility depends on the sorting efficiency and purity of the incoming textile waste. While mechanical recycling cannot handle blended fabrics, glycolysis recycling handles some cotton blends by leaving the cellulose intact for recovery. This process represents a circular pathway for complex garment waste.
