Enzymatic Functionalization of HMLS-Polyethylene Terephthalate Fabrics Improves the Adhesion to Rubber

Abstract

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...