Synthesis of self-healing Castor oil-based waterborne polyurethane based on Diels–Alder reaction

VILLCA, DANNA; COSTA, ALEIX; MUCCI, V.; BRACART, J.

Buenos Aires

Congreso; WCCE11-11th World Congresses of Chemical Engineering; 2023

AAIQ

The ecological impact of waterborne polyurethane coatings made from green, renewable precursors makes them particularly desirable in light of sustainable goals. Due to their low Volatile organic compounds (VOCs) contents, waterborne polyurethanes (WPUs) based on vegetable oil are currently employed extensively as coatings in many different industries. However, aqueous polyurethanes used as coatings can inevitably be damaged during long-term use. Consequently, it is crucial to develop aqueous polyurethane coatings with self-healing capabilities that can heal themselves from damage and thus provide materials with a longer service life 1[1]. Herein, we present a novel type of castor oil-based self-healing waterborne polyurethane that address these issues. We successfully created a number of environmentally friendly, self-healing, and recyclable waterborne polyurethanes based on Diels-Alder (DA)/retro-DA reactions (WPU-DA) by incorporating novel stimuli-responsive Diels-Alder (DA) diol into polymer chains. By adjusting the ratio of -NCO/-OH during the creation process, we created self-healing binders with various DA adduct contents, and further studied the influence of DA adduct and chain extender (Butanediol) content on the mechanical properties and self-healing performance. Moreover, WPU-DA films with outstanding mechanical performance show an excellent self-healing capability due to the couple/decouple process of the DA reactions, and the self-healing process was highly investigated via FT-IR and DSC exhibiting effective reversibility of the DA/retro-DA chemistry2[2]. The networked WPU-DA may also be recycled simultaneously using hot pressing and solution casting. The positive results suggest that WPU-DA has a wide range of possible applications for self-healing coatings in general.