Manipulating bond exchange rates invitrimer-hexagonal boron nitride nanohybrids via heat capacity enhancement

Both thermoplastic and thermoset like vitrimers with dynamic covalent networks have been considered to be strong candidates as matrix materials for incorporating fillers to produce strong but also weldable, recyclable, and functional composites with light weight. As the bond exchange kinetics of dynamic covalent networks are a key factor governing macroscopic properties of vitrimers, substantial efforts have been devoted to manipulating the kinetics by synthesizing vitrimers equipped with new bond exchange chemistries. Here, a facile and synthesis-free approach to increasing the bond exchange rates of a model vitrimer, poly(hexahydrotriazine), is described. It was accomplished by simply incorporating a hexagonal boron nitride (hBN) filler. The incorporatedhBN effectively accelerated the thermally activated bond exchange reactions as evidenced by reduction in both activation energy and relaxation time.