Polymer Scission
Chemical breakdown of macromolecular chains occurs when ester bonds in synthetic filaments undergo solvolysis under controlled conditions. Polyester depolymerization reduces high molecular weight polymers back to monomers or oligomers through glycolysis or hydrolysis. Industrial recycling operations apply this reclamation method to post-consumer apparel waste and defective yarn lots.
Ethylene glycol acts as a reactant in thermal reactors to cleave the polymer backbone at elevated pressures.
Reactor Kinetics
Catalyst concentration dictates reaction rates during pressure vessel processing of post-industrial scrap. Zinc acetate accelerates transesterification when added to virgin resin melts and blended textile waste streams. Temperature control prevents thermal degradation of recovered intermediates prior to downstream purification stages.
Monomer Recovery
Bishydroxyethyl terephthalate crystallizes out of solution following filtration phases designed to remove insoluble contaminants. Distillation columns separate purified chemical fractions from residual dye molecules and spinning finish oils. Analytical chromatography verifies that recovered bishydroxyethyl terephthalate meets purity thresholds required for repolymerization into filament grade chips.
Depolymerization Boundary
Chemical recycling pathways cease functioning effectively when halogenated flame retardants contaminate the feedstock input batches. Contaminants poison metallic catalysts within reaction vessels and disrupt stoichiometric ratios during depolymerization runs. Mixed fiber feedstocks containing cotton or elastane require mechanical separation before material enters chemical reactors.
