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Viscose (also known as Rayon) filaments are obtained from regenerated cellulose and are used in many different sectors mainly as reinforcement material in tires and other cord applications and in the clothing industry. The incorporation of a phosphor-containing pigment imparts flame-retardancy properties to these fibers, which then can be used as part of personal protection textiles delivering wear comfort. There are no recycling strategies for these materials being brought to landfills or chemically degraded since incineration is difficult because of their flame retardancy. In this study, an enzyme-based strategy for the recovery of glucose and of the phosphor pigment without altering their chemical structures was developed as a circular economy solution. Rayon fibers were completely hydrolyzed by a cellulase preparation while 98% of the glucose (reducing sugar assay and HPLC analysis) and more than 99% of the flame-retardant pigment present in the fibers was recovered. The recovered pigment was analyzed...

Among synthetic thermoplastic fiber materials for reinforcement, high modulus and low shrinkage poly(ethylene terephthalate) (HMLS-PET) became the major carcass material for the low- to medium-end tire segment. Usually cords are coated with a resorcinol–formaldehyde–latex (RFL) dip to achieve acceptable power transmission. However, the low concentration of polar groups on the PET’s surface requires an additional activation with costly and potentially toxic chemicals to create additional nucleophilic groups prior to RFL dipping. Here, a green enzyme based alternative to chemical HMLS-PET activation was investigated. Four different cutinase variants from Thermobifida cellulosilytica were shown to hydrolyze HMLS-PET cords, creating new carboxylic and hydroxyl groups with distinct exoendo-wise selectivity. The highest degree of enzymatic functionalization reached a concentration of 0.51 nmol mm–2 of COOH with a release of 1.35 mM of soluble products after 72 h. The chemical treatment with 1 M NaOH released mo...