pps proceeding - Abstract Preview
pps proceeding
Symposium: S08 - Rubbers and Elestomers
Oral Presentation
 
 

Self-healing elastomers based on dynamic covalent urea bond

Wang Zhanhua (1)*, Xia Hesheng (1)

(1) Sichuan University - Sichuan - China

Self-healing elastomers have gained rapidly increasing interest over the last decade, and have been studied and used in an ever increasing range of applications. Herein, we successfully make the covalent urea bond – a pinnacle of stability due to strong resonance effects – dynamic in nature through mediation of zinc salts. The dynamic covalent character of urea in the presence of zinc ions is confirmed through dissociation reaction experiments and quantum chemical calculations of small-molecule model urea compounds. In line with our experiments, the modelling results suggest that the presence of zinc ion speeds up the reaction of the urea dissociation by two orders of magnitude via the formation of O-bound Zn complexes. Based on such dynamic covalent urea bonds, we then develop a novel class of self-healing polymer materials with excellent healing efficiencies. Different kinds of self-healing and reprocessable polyurea elastomers were prepared, with polymer properties that can be easily tuned by varying the crosslinking degree and the molecular weight of the siloxane precursor. Since different kinds of self-healing polyurea materials could easily be prepared due to the commercial availability of a very wide range of amine and isocyanate monomers, this introduction of self-healing properties is expected to have significant potential in a range of applications, such as coatings, paints, and 3D printing. In addition, this introduces polyureas and other urea-containing polymers as a class of highly stable, yet easily reprocessable elastomers, which is highly relevant given a globally desired more sustainable use of plastics.