Controlled creep resistance and melt-flow properties of vitrimers in a facile dual-catalytic system

Abstract

Interest in vitrimers has increased due to the growing importance of recyclable thermosets. Controlling the flow properties of vitrimers to enhance creep resistance and processability presents challenges, particularly in extending the operating temperature range. Herein, a facile approach using a dual-catalytic system with varied activation energies (Ea) was applied to control the creep and flow properties of vitrimers. We employed an asymmetric dual-catalytic system, where a catalyst with a lower Ea facilitated the formation of a highly cross-linked structure, ensuring high creep resistance at low temperatures, while a catalyst with a higher Ea increased the deformation rate at elevated temperatures. The temperature range with distinct stress-relaxation behaviors were observed when the proper asymmetric dual-catalytic system was applied, where creep was effectively suppressed at lower temperatures, and a dormant catalyst with a higher Ea significantly accelerated the exchange reaction upon activation at higher temperatures. These findings and characterization offer valuable insights into the potential for vitrimer properties control, and vitrimer recycling using diverse catalytic systems.