Characterisation and application of polyurethane copolymers grafted with photoluminescent dyes

Abstract

Photoluminescent dyes (aminofluorene, naphthalimide, naphtholbenzein, or phenosafranine) were grafted to polyurethane using an allophanate linkage. The photoluminescence properties and the shape recovery effects of polyurethane samples were investigated. The polyurethane was composed of 4,4′‐methylenebis(phenylisocyanate), poly(tetramethyleneglycol), and 1,4‐butanediol. The dyes were linked through an extra 4,4′‐methylenebis(phenylisocyanate) and the carbamate moiety of the polyurethane chains. Polyurethanes with various dye contents were characterised, and the shape recovery and photoluminescence properties were compared. In the case of the tensile mechanical properties, the highest maximum stress was 56 MPa, and the strain remained > 1500% for the entire series. The shape recovery improved as the test cycle was repeated, with up to 100% recovery being achieved, but shape retention decreased as the dye content increased. Finally, the photoluminescence of the polyurethanes was demonstrated by a luminescent light‐emission test, together with pH indication capability and the preparation of non‐woven fibre using the electrospinning method.