Influence of the Macromolecular architecture on the properties of biobased polyurethane tissue adhesives

Abstract

Polyurethanes (PU) have recently emerged as promising biomaterials for tissue adhesive applications. Compared to other tissue adhesives, they offer substantial advantages such as the possibility to tailor adhesive strengths and curing times, for instance. All these properties are directly affected by the composition and final architecture. In this work, biobased two-components PU sealants were prepared, based on (i) an isocyanate-terminated prepolymer and (ii) a chain extender. Here, an exhaustive evaluation of the oligoester-diols and chain extenders influence on the sealants properties has been performed. In order to bring controlled variations on the final macromolecular architectures, three different prepolymers were prepared: two are based on poly(3-hydroxybutyrate) diol oligomers and another one on poly(lactic acid) diol oligomers, with a 50/50 isocyanate molar ratio of hexamethylene diisocyanate and biobased dimeryl diisocyanate. To study the chain extenders influence, five different aliphatic and linear bifunctional molecules were assessed, with varying length and functional groups reactivity. Ultimately, PUs obtained after the two-component systems curing were also fully characterized. They exhibited an overall good biocompatibility around 80%, with limited cytotoxicity. A wide range of physico-chemical and mechanical properties were also obtained, evidencing the importance of the macromolecular architecture on the systems final properties.